Continuous wakefulness increases demands of sleep, and thus arousal-inducing network and sleep-inducing network should be reciprocally interacted. Histamine has been described as one of neurotransmitters controlling arousal. This hypothesis is in agreement with sleepiness caused by classical anti-histamine drugs, whereas neuronal mechanisms involved are not fully understood. The tuberomamillary nucleus of posterior hypothalamus contains cell bodies of histaminergic neurons. These neurons are tonically active during wakefulness but cease firing during sleep. It has also shown that histaminergic axons are dense in the medial preoptic area (MPOA) and extracellular histamine concentrations in the MPOA couple to arousal states. Our studies also demonstrated that in vivo recordings of action potential firings in the MPOA couple to arousal states in rats. Since preoptic area has been proposed as critical centers for non-REM sleep regulations, we further analyzed distribution of functional histamine receptors using organotypic cultures of mouse MPOA by Ca²⁺ imaging techniques. The results demonstrated that histamine evoked Ca²⁺ transient in MPOA neurons but not in the ventrolateral preoptic nucleus neurons. The Ca²⁺ response in MPOA neurons was resistant to tetrodotoxin but was completely inhibited by the H1 histamine blocker, chlorpheniramine. Since chlorpheniramine has hypnotic effects in vivo, these results suggest arousal signal-feedback to the preoptic sleep centers via histaminergic systems. [J Physiol Sci. 2008;58 Suppl:S91]

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Peroxisome proliferators-activated receptors alpha (PPARα), the isoform of PPARs, is a transcription factor belonging to the nuclear receptor playing a role in lipid metabolism. It is also reported that the treatment with bezafibrate, which is a PPARα ligand, showed phase-advanced locomotor activity in mice. We examined the effect of the bezafibrate treatment on sleep and body temperature rhythm. Mice were fed with a control diet for two weeks, and were recorded body temperature, electroencephalogram and electromyogram for 48 h, under light/dark conditions. After the baseline recording, these mice were fed with bezafibrate containing diet for 2 weeks, after which the same recordings were carried out. Acrophase of rhythm for locomotor activity and body temperature were about 2 h advanced after 2-week feeding of bezafibrate in comparison with the baseline. Sleep/wake rhythm were also phase-advanced about 3 h. Furthermore, bezafibrate treatment increased the EEG delta power in non rapid eye movement (NREM) sleep compared to the baseline. These data suggest that chronic bezafibrate treatment could advance a sleep/wake and body temperature rhythm as seen in locomotor activity, and PPARα might be involved in the regulation of delta power in NREM sleep. [J Physiol Sci. 2008;58 Suppl:S91]

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Senescence-accelerated prone (SAMP) mice are model of accelerated aging which was established through phenotypic selection. SAMP8, one of the substrain of SAMP, is known to exhibit an age-related deterioration in learning and memory abilities in comparison to normal aging mice (SAMR1).Same as learning and memory abilities, it is accepted that the age-related deterioration occurs in the sleep-wake states in human and experimental animals. Also in SAMP8 and SAMR1 mice, it is reported that the aging induces the deterioration of sleep-wake architecture and delta power during non-REM sleep both strains. However, the difference between SAMP8 and SAMR1 mice was reported to show only in REM sleep. To confirm the deterioration of sleep architecture in SAMP8 mice in comparison with SAMR1 mice, we carried out the recording of electroencephalogram (EEG) for 24-hour on 10-12 months old SAMP8 and SAMR1 mice. Furthermore, in order to see the homeostatic function, 6-hour sleep deprivation (SD) and the recording during the recovery period from SD were performed. SAMP8 mice showed the significant increase of wakefulness and decrease of non-REM and REM sleep. The delta power during non-REM sleep was attenuated than SAMR1 mice in dark phase. Furthermore, the recovery of delta power induced by 6-hour SD was attenuated in SAMP8 mice.Our results suggest that the sleep architecture and homeostatic control is disturbed in SAMP8 mice in comparison to SAMR1 mice. [J Physiol Sci. 2008;58 Suppl:S91]

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Clock gene expression rhythm in the dorsomedial hypothalamic nucleus (DMH) correlates well with food-anticipatory activity (FAA) rhythm. As acute feeding (AF) after fasting is an important first step to establish FAA rhythm, we examined the involvement of the DMH in both AF and FAA processes. AF elicited NMDA receptor-dependent expression of mPer1 and/or mPer2 mRNAs drastically in the DMH and weakly in the arcuate nucleus (ARC), the nucleus of solitary tract (NTS) and area postrema (AP). DMH lesions did not affect AF-induced mPer mRNA expression in the ARC, NTS and AP. Daily restricted feeding (RF) for 4 hrs caused a rapid phase shift and increased amplitude of mPer1 and mPer2 mRNA and mPER2 protein expression rhythms, not only in the DMH, but also in the ARC and cerebral cortex. DMH lesioning resulted in an overall decrease in activity level; however, it failed to abolish FAA rhythms under light-dark and constant darkness conditions. Furthermore, RF-induced daily rhythm of mPer2 mRNA in ARC and cortex was unaffected in DMH-lesioned mice. Although clock gene expression in the DMH is susceptible to AF, it is not necessary for the performance of AF and FAA rhythms. Thus, the present results suggest that multiple areas distributed throughout the brain, including the DMH, may be involved in the establishment of the FAA rhythm. [J Physiol Sci. 2008;58 Suppl:S91]

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We examined the effect of unilateral chemical lesion of the red nucleus (RN) on feeding and drinking behavior in rats. Daily food and water intake were recorded, commencing 5 days prior to surgery. Daily food intake was assessed by subtraction of the number of spillage of pellets, from the number of ingestion of pellets for 24 h using a food intake monitor. Daily water intake was assessed by counts of drops of water for 24 h using a drink sensor. Kainic acid (0.1 μl, lesion group) or phosphate-buffered saline (0.1 μl, control group) was injected into the left RN. The number of ingestion of a pellet and a drop of water were counted for 24 h over the first 10 days after surgery. There was no significant difference in the mean body weight between the lesion and control groups, or in the mean number of ingestion of pellets or in the mean number of spillage of pellets or in the mean number of drops of water before surgery. Lesion group was a significantly loss in body weight at 1, 2, 3, 4, 5, 6 and 8 days after surgery. The mean number of ingestion of pellets of lesion group was significantly decreased at 1 and 2 days after surgery. The mean number of spillage of pellets of lesion group was significantly increased at 3, 7, 8, 9 and 10 days after surgery. The mean number of drops of water of lesion group was significantly decreased at 1 day after surgery. These results suggest that the RN is involved in the control of feeding behavior. [J Physiol Sci. 2008;58 Suppl:S92]

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We have already reported that both acquisition and retention of the conditioned taste aversion memory (CTAM) were markedly suppressed in C57BL/6 male mice when the gravity disturbance was applied between 0.1% sodium saccharin as a conditioned stimulus (CS) and an i.p. injection of 0.15 M LiCl as an unconditioned stimulus (US) using 3D clinostat to cancel the gravitational force. However, gravitational disturbance applied before CS never affected the acquisition and retention of CTAM. Muscarinic acetylcholine receptor (mAChR) have been reported to contribute to discrimination process of novel tastants from familiar ones. Therefore, we employed knockout mice for two subtypes (M1 and M3) of mAChR to examine contribution of mAChR to gravitational modulation of acquision mechanism of conditioned taste aversion memory. Both acquisition and retention of CTAM were suppressed in M1 knockout mice (M1KO) with the gravitational disturbance, whereas in double knockout mice of M1 and M3 (M1/M3KO), the CTAM was not affected. These results suggest that the gravitational disturbance prevents CTAM formation through suppression of association process between CS and US, and M3 receptors play more important role for mice to accept gravitational disturbance rather than discrimination among taste qualities. [J Physiol Sci. 2008;58 Suppl:S92]

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We have already reported that the degree of the retrieval in the condition taste aversion memory (CTAM) represents age-related differences during sexual maturation of mice, suggesting the hormonal effect secreted temporally during maturation period on the extinction mechanism of CTAM. We chose an androgenic hormone, testosterone, in order to examine the effect of sexual maturation on acquisition and retention of CTAM. Gonadectomized male mice (C57BL/6J) were implanted with pellets containing several doses of testosterone (0-2 mg) at 5 weeks after birth. At 7 weeks, mice, which acquired CTAM by application of 0.5% sodium saccharin as a conditioned stimulus (CS) and an i.p.injection of 0.15 M LiCl as an unconditioned stimulus (US), were followed by the extinction period for 1 week. At 12 weeks, mice implanted the silicon tube containing 0.5 and 1.0 mg testosterone showed significantly higher retrieval than mice implanted not only the silicon tube containing 0 but also 2.0 mg testosterone. Thus, these results suggest that testosterone participates in the maturation process of the extinction mechanism of CTAM in the mice brain. [J Physiol Sci. 2008;58 Suppl:S92]

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The emotional learning such as fear conditioning is likely to be inhibited during the lactation period. We examined whether conditioned taste aversion (CTA), a kind of the emotional learning, is also inhibited during the lactation period or not. When 0.2% sodium saccharin as a conditioned stimulus (CS) was followed by an i.p. injection of 0.15 M LiCl as an unconditioned stimulus (US), the acquisition of CTA memory (CTAM) of lactating mice was comparable to those of naive female mice. However, the extinction of the lactating mice significantly delayed more than that of the naive mice. In the two-bottle preference test, mice during the lactation period preferred water rather than high concentration of saccharin, whereas naive and post-lactating female mice preferred saccharin over all the concentration tested. In contrast, all the mice preferred sucrose much to water. Oxytocin, a nonapeptide hormone, which is produced in the hypothalamus and secreted from the posterior pituitary gland during the late pregnancy or lactation period, is thought to contribute to the social behavior such as maternal behavior. Therefore, we tried to inject oxytocin to the lateral ventricle. Both acquisition and retention of CTAM in the oxytocin-injected mice were markedly raised more than those of the sham-operated mice, suggesting that oxytocin secreted during the lactation period affects the acquisition and/or retention mechanisms of the CTAM. [J Physiol Sci. 2008;58 Suppl:S92]

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Estrogen receptor (ER)α is a ligand-dependent transcription factor that is important for the display of social behaviors in male and female mice. ERα is expressed in both neurons and glia throughout the central nervous system (CNS). Previous work showed that sexual and aggressive behaviors are greatly reduced in male ERα KO mice. To investigate the contribution of neuronally-expressed ERα to these behaviors, we investigated social behaviors as well as home-cage running wheel activity in male mice that lack ERα selectively in neurons (ERα fl/fl) of the CNS but possess ERα in glia and peripheral tissues. Adult male mice were tested on a range of social behaviors, including aggressive behavior against olfactory bulbectomized male intruders and sexual behavior toward hormonally primed female mice. Among the ERα fl/fl mice, aggression was greatly reduced and sexual behavior was abolished compared to wild-type (WT) mice. In addition, increase in running wheel activity normally observed in gonadectomized WT mice after estrogen implantation was not seen in ERα fl/fl mice. These data suggest that sex and aggressive behaviors in males are governed by ERα expressed in neurons. Supported by Grant-in-Aid for Scientific Research 17052001 and 17330151 to SO. [J Physiol Sci. 2008;58 Suppl:S93]

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Estrogen in the neonatal period plays a major role in the development of sexually dimorphic behaviors by acting through estrogen receptors (ERs). Though two types of ERs, ERα and ERβ, are identified, their role in the neonatal period to influence emotional and social behaviors in adulthood are largely unknown. Hence, we compared the effects of neonatal estrogen administration on the levels of anxiety, social investigation, and aggressive behaviors in ERβ knockout (βERKO) females with those in wild-type (WT) control mice. Female pups were administered with either estrogen benzoate (EB) or the vehicle (sesame oil) daily from postnatal day 1 through 3. All mice were, as adults, gonadectomized, EB substituted with a long-term release pellet, and individually housed. They were then tested for anxiety-related behaviors on the light-dark transition (LDT) test, social interaction with a novel same-sex mouse, and male-type aggressive behavior against olfactory bulbectomized male intruders in a resident-intruder paradigm. In WT mice, neonatal EB administration increased the levels of anxiety as seen by decreased time and distance traveled in the light compartment during LDT tests. Correspondingly, it also decreased interaction with a same-sex animal, and increased aggressive behavior. Lack of ERβ abolished the neonatal EB effect on anxiety and social interaction in adults, demonstrating the importance of ERβ in mediating the neonatal EB effect on these behaviors. (Supported by KAKENHI 17052001 to SO and the 21st Century COE Program to KX and SO.) [J Physiol Sci. 2008;58 Suppl:S93]

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We examined the sexual odor preference and opposite sex odor-induced Fos expression in forebrain regions using sexually experienced and naïve Long-Evans rats of both sexes. The sexually experienced males significantly preferred estrous female-soiled bedding over male-soiled bedding. In these animals, exposure to estrous bedding increased of Fos expression throughout the vomeronasal projection pathway (the VN pathway), i.e., posterior-dorsal medial amygdala (MePD), the bed nucleus of the stria terminalis (BNST) and the medial preoptic area (mPOA), and also in the nucleus accumbens (NAcc) core and shell. The sexually naïve males, however, did not show preference for estrous odor, and estrous odor-induced Fos expression was restricted to the peripheral portion of the VN pathway, i.e., MePD. Unlike male rats, female rats preferred male bedding over estrous bedding irrespective of the presence or absence of prior sexual experience. In both the sexually naïve and sexually experienced female rats, exposure to male bedding significantly increased Fos expression in the BNST and the MePD although Fos increment in the mPOA and the NAcc core was observed only in the sexually experienced subjects. These data suggest that mPOA, the BNST and the NAcc in male rats and the MePD and the BNST in female rats are candidate brain regions involved in the expression of preference for opposite-sex. [J Physiol Sci. 2008;58 Suppl:S93]

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The posterior-dorsal medial amygdala (MePD) contains a large amount of sex steroid receptors and processes pheromonal signals. The involvement of the MePD in the expression of male-directed odor preference of female rats was investigated. In experiment 1, ovariectomized female rats were bilaterally implanted with guide cannulae aimed at the MePD. These rats were primed with estrogen benzoate (EB) and pretested for the expression of preference for air-borne odors from a sexually active male as opposed to an estrous female. Three weeks later, these subjects were retested to confirm that the odor preference was completely eliminated, and then they were implanted with either 100% crystalline estradiol (E) (High E Group) or 10% E (diluted with choresterol; Low E Group) through inner cannulae (30-gauge) 48 h prior to behavioral testing. Odor preference was restored in neither group. In High E Group, however, lordosis behavior was observed. This suggests that at least in this group the level of estrogen in the vicinity of the MePD, such as the ventromedial nucleus of hypothalamus, was high enough to induce physiological events. In experiments 2, implantations of tamoxifen (anti-estrogen) were made instead of E through inner cannulae (24-gauge) together with EB priming 48 hr prior to behavioral testing. Odor preference was not restored by these treatments although lordosis behavior was observed. Taken together, these results suggest that estrogen activation at the MePD was necessary, but not sufficient, to express male-directed odor preference of female rats. [J Physiol Sci. 2008;58 Suppl:S93]

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Urocortin II (UCN II) is a newly identified peptide that belongs to the corticotropin releasing factor (CRF) family, and acts as a feeding suppressant via CRF 2 receptors (CRF2-Rs). The ventromedial nucleus of the hypothalamus (VMH) is known as a satiety center in the brain and expresses abundant CRF2-Rs. However, the actions of UCN II on VMH neurons are remained unclear. Thus, we examined the effects of UCN II on VMH neurons using brain slice preparations and extracellular and whole cell patch clamp recording techiniques. In extracellular recording, bath-application of UCN II excited about 60% of VMH neurons recorded, and the excitation was dose-dependent and persisted in the Low Ca²⁺-high Mg²⁺ ACSF. Pretreatment with antisauvagine-30 (aSVG-30), a selective antagonist for CRF2-R, abolished the excitation induced by UCN II. In whole cell patch clamp recording, the membrane resistance decreased during the UCN II-induced depolarization. When the current-voltage relationship was measured in voltage clamp mode, the reversal potential was about -48 mV, suggesting an involvement of non-selective cation channels in UCN II-induced depolarization. These results suggest a possibility that UCN II participates in the feeding suppression through the excitaion of VMH neurons. [J Physiol Sci. 2008;58 Suppl:S94]

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In this study we examined whether spontaneous locomotor activity could restore the leptin resistance induced by high fat diet (HFD) feeding in rats. Adult male rats were given HFD (fat content 60%) to make obese animal model. There was no difference in calorie intake between normal diet fed and HFD fed rats. On 50 days of HFD feeding, body weight, fat pad weight and the serum leptin level were increased. In these obese rats icv injection of leptin showed no inhibitory effect on food intake. These rats were moved to running wheel cage, in which they can run voluntarily. On 10 days of voluntary running in the wheel cage, fat pad weight and blood leptin level tended to decrease, and icv leptin injection inhibited food intake. The intracellular signal of leptin receptor activation was estimated by phosphorylation of STAT3 (pSTAT3) protein using immunohistochemistry in the brain of icv leptin injected rats. In HFD fed rats, the number of pSTAT3 positive cell was decreased in the arcuate nucleus (ARC) and the ventromedial nucleus of the hypothalamus (VMH). Voluntary running for 10 days increased the number of pSTAT3 positive cell in the VMH, but not in the ARC. These results suggest that 10-day voluntary running in the wheel cage restores the leptin resistance and the pSTAT3 signals within the VMH might be involved in this restoration of leptin resistance. [J Physiol Sci. 2008;58 Suppl:S94]

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The common marmoset (Callithrix jacchus), is a small nonhuman primate, which shows efficient reproduction and rapid postnatal growth. This species provides an ideal experimental animal model to study postnatal development of higher brain function. It is known that common marmosets typically give birth to twins under natural conditions. In captivity, births of triplets are common, although parents rarely succeed in rearing more than two offspring. In addition, some developmental studies require experimental conditions using isolated neonates from their parents. Thus, neonates are frequently raised by humans ever since they were born. During lactation period, however, diarrhea often emerges in marmoset neonates fed on conventional milk for humans, and dehydration after diarrhea is a leading cause of death in early neonates. Weaning rates are previously reported to be about 80%. Here we report an improved method for artificial rearing of the common marmoset. We have developed an original recipe of milk and protocol for feeding to increase weaning rate. Using our original milk, the neonates rarely suffered from severe diarrhea. In recent 2 years, continuous 17 neonates were successfully weaned in our laboratory. [J Physiol Sci. 2008;58 Suppl:S94]

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Common marmosets (Callithrix jacchus), day-active primates, were raised artificially from birth under one of 3 lighting conditions: a 12h light and 12h dark cycle (LD12:12, n=3), constant light (LL, n=4), or constant complete darkness (DD, n=1). Under each condition, spontaneous locomotor activity was detected about 10 days after birth. Marmosets in LD12:12 showed entrained circadian activity rhythms with activity periods corresponded to the light period. In LL, marmosets showed free-running circadian rhythms with periods longer than 24h ( mean 24.71h) during first 2 months. Periods of free-running rhythms begun to decrease around postnatal day 100, and finally they became shorter than 24h until postnatal day 130. In DD, a marmoset showed less activity than animals in LD12:12 and LL. The animal showed a split circadian activity rhythm free-running with a period shorter than 24h (23.5h). On postnatal day 121, the animal was transferred into LD12:12. Behavioral tests suggested that the animal had a severe damage in visual function, however its circadian rhythms quickly entrained to the LD cycle. [J Physiol Sci. 2008;58 Suppl:S94]

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Twenty-six experimental crayfish were trained to maintain a leg position above a specified level, below which the animal received the electric or magnetic shock. The training limit was five 20-min training sessions, each of which was followed by a 10-min rest period. During the training period, a yoke-control animal was arranged in a series with the experimental animal, and received a pattern of aversive stimuli identical to that received by the experimental animal but independent of its own leg positions. The commonest learning course was characterized by sudden and steep improvement of performance by electric stimulation, although gradual improvement was observed in some animals by magnetic stimulation. There are variations in the performance among specimens: some avoided the shocks by maintaining, the raised leg positions; in others the periods of raising legs were interrupted by periods of gradual lowering of the leg resulting in several shocks. Three yoke-controls also acquired appropriate leg positions, but this probably resulted from accidental association between the leg position and the shock. Crayfish with disconnected cephalic ganglion trained on leg position learning also learned to avoid magnetic shocks within one or two training sessions. The demonstration of leg position learning in the crayfish by magnetic stimulation enhances the utility of this animal as a model for the detailed analysis of neural mechanisms underlying behavioral plasticity. [J Physiol Sci. 2008;58 Suppl:S95]

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The mammalian circadian clock governs daily rhythms of physiological function including sleep, activity, energy metabolism, and circulation. Genetic approaches to elucidate the circadian clock have revealed the core mechanism of the molecular clock that generates the circadian rhythm at both molecular and cellular levels. Recent studies indicate that cardiovascular function such as the regulation of blood pressure and heart rate is under the control of the molecular clock. However, little is known about how the molecular clock transmits the circadian signal to the regulatory mechanism of circulation to produce the cardiovascular circadian rhythm at the organismal level. Here we show that prokineticin 2, a downstream molecule of the molecular clock, regulates cardiovascular function in rats. Both prokineticin 2 and its specific receptor were abundant in the nucleus tractus solitarius, a core central target that regulates cardiovascular function. Interestingly, microinjection of prokineticin 2 into the nucleus tractus solitarius of rats decreased blood pressure and heart rate predominantly during the light period when rodents normally sleep. Our results suggest that prokineticin 2 may play an important role in the generation of the circadian rhythm in circulation. [J Physiol Sci. 2008;58 Suppl:S95]

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Ghrelin is produced in some peripheral organs and brain, and acts as a stimulator for growth hormone (GH) secretion and food intake via GH secretagogue receptors (GHS-Rs). Recent studies further suggest that ghrelin participates in the regulation of sleep-wakefulness. Pedunculopontine tegmental nucleus (PPT), which is one of brain sites that control sleep-wakefulness, also expresses GHS-Rs. However, the action of ghrelin on PPT neurons is remained unclear. Thus, we examined the effects of ghrelin on PPT neurons using rat brain slice preparations and whole-cell patch clamp recording technique. Bath-application of ghrelin depolarized PPT neurons, and the depolarization persisted in the presence of tetrodotoxin. The ghrelin-induced depolarization was accompanied by increase of membrane resistance. When extracellular K⁺ concentration was increased or extracellular Na⁺ was replaced by N-methyl-D-glucamine⁺ (NMDG⁺), the ghrelin-induced depolarization significantly decreased, but did not disappear. However, when external solution was modified together with the increase of extracellular K⁺ and the replacement of extracellular Na⁺ with NMDG⁺, the depolarization disappeared completely. These results suggest that ghrelin depolarizes PPT neurons via closing of K⁺ channels and activating of external Na⁺ influx pathway, and participates in the regulation of sleep-wakefulness through the excitatory effects on PPT neurons. [J Physiol Sci. 2008;58 Suppl:S95]

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We developed the monitor the daily rhythm of respiration pattern by whole body plethysmography(WBP) using ovalbumin (OVA)-induced asthma model mouse. There are small difference of tidal volume, minute volume/body weight and respiratory frequency, but the Tienh (Ti/Te x Pe/Pi; Te/Ti,Time inspiration /Time expiration; Pe/Pi, Pressure increase by expiration/Pressure decrease by inspiration (to averaged P line) showed the circadian pattern in the asthma model mouse but not in the normal mouse. Thus, Tienh is good index for lung resistance and high Tienh represents inspiratory obstruction in asthma model mouse. A value of Tienh was higher during daytime (ZT4-7) and lower in the night time (ZT16-19). It is well known that smoking of tobacco worsens the asthmatic symptom. Therefore we asked whether smoking of tobacco affects the Tienh of respiration of the asthma model mouse. We prepared the three different type of tobacco depending on the content of nicotine and tar. Tobacco smoking elevated the value of Tienh depending on content of nicotine and tar both in normal and asthma model mice. Further experiments are required to show the effect of chronic exposure of tobacco smoking on Tienh value. The present results suggest that tobacco smoking worsens the respiratory response in the daytime (night time for humans), because respiration deficit may show circadian pattern. [J Physiol Sci. 2008;58 Suppl:S95]

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In chronic recording experiments, self curing dental acrylic resins have been used widely as a mounting base of electrodes or microdialysis-probes. Since these acrylics do not bond to the bone, screws have been used as anchors. However, in small experimental animals like finches or mice, their craniums are fragile and can not successfully hold the anchors. In this report, we propose a new application of light-curing dental adhesive resins for mounting base of chronic recording electrodes or probes in freely moving animals. Compared to the application of conventional self curing resins, this material has several important advantages. Firstly, this material allows direct bonding to the cranium. Therefore, anchor screws are not required and surgical field can be reduced considerably. Past experiences have shown that the bonding effect maintains more than 2 months. Secondly, it is easy to handle. Conventional resin's window of time, when the materials are pliable and workable, is within a few minutes. However, the window of working time for this light curing dental adhesive resin is significantly wider and adjustable. Thirdly, reaction does not generate heat. Curing reaction of self-curing resin is exothermal. When the mounting base is thick, this heat accumulates and may damage the tissue. Reaction of light curing resin does not generate such heat. In this report, we used the finches as subjects. It is also advised that this technique is applicable to chronic implantations of electrodes or probes in other experimental animals such as frog, mouse, and monkey. [J Physiol Sci. 2008;58 Suppl:S96]

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Arsenic is an environmental toxicant because of its toxic properties and extensive presence in the environment. It is reported to cause adverse effects on the nervous system. Previous reports had confirmed the correlation of oxidative stress with arsenic. On the other hand zinc is an essential trace element and is known to possess antioxidant properties. The present study evaluated the role of zinc in toxic conditions induced by arsenic in female wistar rats. To carry out the investigations, rats were segregated into four treatment groups: Animals in group I (normal control) were fed standard laboratory feed and water ad libitum throughout the study. Group II animals received arsenic in the form of sodium arsenite orally with the help of a blunt tip canulla at a dose level of 100ppm. Rats in group III were given zinc in the form of zinc sulphate at a dose level of 227mg/L orally. Animals in group IV received a combined treatment of zinc and arsenic in a similar way as given to animals belonging to group II and III, respectively. All the treatments were given for a total duration of 8 weeks. Behavioral studies were conducted by studying total locomoter activity, anxiety as well as muscle relaxant activity. Rats treated with arsenic showed a significant decrease in the levels of acetyl choline esterase as well as in the locomoter and muscle activity when compared to normal controls. Interestingly when Zinc was supplemented to arsenic treated group, the already decreased activity of ACI in arsenic treated rats was observed to be increased significantly. [J Physiol Sci. 2008;58 Suppl:S96]

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Effects of habitual physical exercise on bone health status in college female athletes; judo, long distance runners, volleyball players, and swimmers (n=32) and the aged women; walkers/joggers, tennis players, gate ball players, and swimmers (n=49) were studied. Health status on Calcaneus was measured twice at intervals of 11 to 12 months by the ultrasound methods. The results were as follows; 1) The% YAM and% age matched in college swimmers and long distance runners were significantly lower compared with judo and volleyball players. 2) In the% YAM and% age matched, there were no-significant differences between college swimmers, long distance runners and age-matched non-exercise controls. 3) The% YAM and% age matched in elderly swimmers was decreased significantly during 11 months. But tennis players were increased% Age matched and% YAM during 10 months. The walkers/joggers and gate ball players showed no significant changes in bone status. 4) The walkers/joggers, tennis players and gate ball players had received lectures and guidance to osteoporosis and health promotion, further who had intake more milk than the swimmers. 5) From the results of this study, it is suggested that judo and volleyball has good effects on bone health status increase in youth period. Further, it is important for middle-aged and elderly women to do mild physical exercise, intake calcium in milk and receive education about osteoporotic disease. [J Physiol Sci. 2008;58 Suppl:S96]

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Many lines of evidence indicate that infants prefer infant-directed (ID) speech to adult-directed (AD) speech. Head-turn preference procedure (HPP) was designed to infants' attentional and/or affective preference for ID over AD speech (Fernald 1985). In this study, to examine whether infants prefer the ID speech to the AD speech (reading picture books in Japanese) recorded in the previous work (Nakagawa 2007), the random version of HPP (Jusczyk 1995) as follows was conducted: A three sided booth lighten dimly was used. The infant was seated on her/his mother's lap and facing the center panel. The video camera behind the center panel recorded the infant behavior through the hole in the panel. At the beginning of the trial, to draw the infant attention, a blue light on the center panel began to flash. When the experimenter judged the infant's eyes were at midline, the center blue light was extinguished. Then a red light on only one of the two side panel decided at random began to blink. After the infant had made a head turn in this direction, a 4-second speech stimulus was played from a loud speaker on that side. Twelve trials were conducted for each subject. Fifteen 7- to 10-month-old infants (mean age: 8.2 months ± 0.94) participated as subjects. As a result, 11 of 15 subjects gazed longer at the direction of the speech stimulation when listening to ID speech than when listening to AD speech. [J Physiol Sci. 2008;58 Suppl:S96]

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Upon FcεRI stimulation, mast cells secrete inflammatory cytokines and chemical mediators are related to allergic inflammation. FcεRI complex shows a tetrameric structure composed of three distinct polypeptides, which include the IgE-binding α chain, the four-folded membrane-spanning β chain, and the disulfide-linked γ- γ homodimer. The β chain acts as an amplifier for allergic reaction in mast cells. The β chain ITAM shows a notable depature from the consensus immunoreceptor tyrosine-based activation motif (ITAM) sequence with the presence of the third tyrosine between the two canonical tyrosines (YX5YX3Y). Our previous study revealed that degranulation and leukotriene production were impaired in cells expressing the mutated FcεRI β ITAM (FYY, YYF, FYF, FFF). However, cytokine production was enhanced in the YFY and FFF mutant. Here, we describe conformational studies of the C-terminal 43 peptide of wild type and mutated FcεRI β ITAM motifs FFF, FYF, YFY, FYY and YYF by circular dichroism(CD) spectroscopy. All of the far-UV CD spectra of WT, FFF, FYF, YFY, FYY, and YYF give typical α-helical feature. The temperature dependence of CD signal showed that midpoint temperature (Tm) decreased by almost 2 degree in FFF and YYF compared to that in WT. Near-UV CD of mutated FcεRI β chains are still ongoing. [J Physiol Sci. 2008;58 Suppl:S97]

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For isolation neural stem cells (NSCs), long-term in vitro cultivation is necessary because of the lack of valid cell surface markers suitable for prospective purification, although long term cultivation may lead to phenotype deterioration. Here, we focused on oligosaccharide chains on NPC surface as a valid marker for isolation. Fluorescence-activated cell sorting (FACS) analysis and immunohistochemical analysis revealed the expression of biantennary complex type N-glycans that recognized by erythroagglutinating-Phaseolus vulgaris agglutinin (E-PHA) lectin in nestin-positive cells in the neurogenic area. In addition, E-PHA bound preferentially to purified NSCs as well as to astrocytes, but not to neurons, microglia, and oligodendrocyte precursor cells. Such high affinity E-PHA binding to NSCs prompted us to use E-PHA as a cell surface marker for NSC isolation by using FACS. In E-PHA binding cells, we found about 30-fold increase in the number of neurosphere-forming cells, capable of differentiating into mature neurons or glial cells, compared to that of non-sorting cells. This indicates that E-PHA, which recognizes complex-type N-glycans, is a valid cell surface marker of mouse NSCs for prospective isolation. [J Physiol Sci. 2008;58 Suppl:S97]

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Distribution of c-Fos immunoreactive neurons in the brain after intraperitoneal injection of leptin in Wistar ratsKiyoshige Takayama, Haruka Kawata, Ryohta Takahara, Kazuhide Tomita (Dept. Lab. Sci., Gunma Univ. Sch. Health Sci. Maebashi, Japan) Leptin has been known to be involved in the regulation of food intake and energy balance. We aimed to survey central neurons that might be activated after peripheral administration of leptin, by examining the distribution of neurons expressing c-Fos. Leptin dissolved in saline (500 μg/kg) was intraperitoneally injected in Wistar rats. One and a half hours after the injection, rats were transcardially perfused with saline and fixed with fixatives. The brain was removed and sectioned at 40 μm. Every fourth section was treated with anti-c-Fos antiserum, and c-Fos protein was immunohistochemically stained using the avidin-biotin complex method. Control rats were injected with saline, and brain sections were processed similarly as described above. It was found that leptin injected intraperitoneally induced the neuronal expression of c-Fos protein in several nuclei throughout the brain. In the central nucleus amygdala, ventromedial nucleus of hypothalamus, periaqueductal gray matter, lateral parabrachial nucleus, and the solitary tract nucleus, numbers of neurons expressing c-Fos protein were much more in the test experiments than those in the control experiments. Intraperitoneally injected leptin was found to stimulate central neurons that may play some roles in the regulation of such as a food intake. [J Physiol Sci. 2008;58 Suppl:S97]

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The present study examined the effects of combined treatment with exercise and ARB, Olmesartan, on visceral fat(VFM) and adipocyte cellularity, which induces metabolic syndrome, using the obese model (OLETF) rats. At 25 weeks of age, thirty male OLETF rats were randomly divided into four groups. The exercise treatment consisted of daily exercise. The antihypertensive drug, Olm was given at a dose of 10 mg/kg body weight/day. OLETF-Ex group exercised voluntarily, and OLETF-Ex+Olm group also exercised. Each treatment was conducted between 25 and 30 weeks of age. Abdominal subcutaneous fat (SFM), VFM and skeletal muscles mass (SMM) were weighed. The epididymol fat cell sizes were classified in 20x10(-6)m increments based on the diameter of adipocyte. Exercise and the combination of exercise with ARB reduced abdominal fat masses and improved both GI and dyslipidemia. However, there were no significant multiplicative effects of combing exercise and ARB. Exercise was the most effective in downsizing epididymal fat cells. Treatment with Olm only also significantly reduced BW, downsized adipocytes, and improved GI and dyslipidemia. However, the mechanisms for BW reduction with Olm remain unknown. This study concluded that there were no multiplicative effects of combined exercise with ARB, Olmesartan, on VFM and/or adipocyte cellularity. [J Physiol Sci. 2008;58 Suppl:S97]

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It has been reported that unilateral, noxious somatic stimulation of the elbow joint increases cerebral blood flow (CBF) over broad, bilateral areas of the cerebral cortices in anesthetized cats, in association with an increase in systemic arterial pressure (Exp. Brain Res., 1998; 118:439). The present study was designed to re-examine this phenomenon in cats that had their spinal cord transected at the first thoracic segment, in order to eliminate the confounding effects of elevated systemic blood pressure on CBF. Noxious cutaneous pinching of a forepaw or noxious inward and outward rotation of an elbow joint for 20-30s resulted in a significant increase in CBF in cats spinalized at the T1 level. Specifically, blood flow increased in the forelimb area of primary somatosensory cortex contralateral to the side stimulated; the systemic blood pressure in these animals remained unchanged. These data suggest that the increases in CBF in the other brain regions described previously in somatically stimulated cats were indirectly due to the increased blood pressure seen in those animals. Our results are discussed in the context of data reported in anesthetized rats whose spinal cord was transected at the upper thoracic level. [J Physiol Sci. 2008;58 Suppl:S98]

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In regards to the health maintain on brain, lots of attention is paid. Dementia and recognition symptom are observed if the blood circulation is blocked. At the same time great number of people are suffering from the stressful daily life. In this study, we investigated the effects of bone conduction of music on EEG and ultrasonic vibration on blood circulation. Two kinds of treatments were applied. The first one was music vibration. It was applied from the lateral side of the head. Twelve minutes music, three pieces of Mozart were played using the bone conduction method. The second one was ultrasonic vibration. Ten minutes of ultasonic vibration, every 1.5 seconds and the duration was for 0.2 seconds, was given from the frontal side of the head. Two devices were activated alternately. EEG was recorded before and after the treatments. Thermo-graph and Xenon CT were also taken before and after the treatments. Salivary amylase activity, blood pressure and heart rate were measured, as well. EEG alpha waves were increased by the treatments. Salivary amylase activity was decreased by the treatments. Blood pressure and heart rate were reduced by the treatments. Facial circulation was increased by the treatment according to the thermo-graph. CT showed the blood circulation of the deep region of the brain was also increased by the treatments. It is concluded that the music and ultrasonic vibration were effective on stress and improvement of the blood circulation. [J Physiol Sci. 2008;58 Suppl:S98]

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In vivo NIRS is a noninvasive functional brain-mapping method that allows relatively free postures. Near-infrared light (NIR) emitted from a probe on the head surface penetrates to the brain, and is scattered back to a detector on the scalp a few cm away. The changes in the attenuation of the detected NIR reflect primarily the changes in concentration and oxygenation of hemoglobin along the optical path. Modern NIRS systems position emitter and detector probes in a rectangular lattice with a fixed probe distance of 2.5–3 cm, with the distances between the centers of the recording ("channels") being 1.75–2.1 cm. In the present study, we explored the usefulness of higher-density recording (a 0.75 cm channel distance) for improving the resolution of functional mapping. NIRS responses to finger tapping were recorded from the contralateral motor area. Although the responding channels to the tapping by the thumb and the little finger overlapped, their peak positions were different in the majority of the subjects, by about 1 cm on average. In other subjects, the barycentric positions of the activities were separated according to the fingers used, although the peak positions were same. These distances between the active centers are consistent with previous studies using fMRI or MEG. The present results suggest that the high resolution NIRS can resolve less than 1.5 cm difference in the localized activity in the brain, in spite of the spread of the NIR in the brain. [J Physiol Sci. 2008;58 Suppl:S98]

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The afferent fibers in the vagus nerve transmit visceral information encoded as varying firing frequency to the second-order neurons in the nucleus of the solitary tract (NTS) and the dorsal motor nucleus of the vagus (DMX) in the solitary complex (SC). Excitatory synaptic transmission between primary afferents and second-order neurons shows distinct short-term plasticity depending on the postsynaptic cell type, which is also related to distinct decay rate in response to high-frequency repetitive stimulation of the afferents (Yamamoto et al., 2006). To reveal the distinct synaptic mechanisms that underlie the different short-term plasticity, we estimated the release probability, quantal EPSC size and the number of release sites based on the mean and variance of the EPSC amplitude recorded at various extracellular Ca²⁺ concentrations in brainstem slices from young Wistar rats. The results indicate that the release probability is negatively correlated with the paired-pulse ratio and that the number of release sites is negatively correlated with the release probability, suggesting that release probability is the primary determinant of the short-term plasticity and the subsequent frequency-dependent filtering properties in the SC. [J Physiol Sci. 2008;58 Suppl:S98]

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We had been developed the biotelemetry system for recording neural signals and other biological signals. In this time, we improved the modulation and demodulation circuits to receive high frequency pulse train about 50kHz. Generally, at the radio, carrier frequency deviation is decided by the manual. Therefore, it is difficult to find the system, which has high-speed response.However, bio-telemeter required more high-speed modulation for more biological information. Then, we also improved the IF (intermediate frequency) amplifier, able to amplified the high-frequency modulated pulse train.This system has employed FM-PWM (frequency modulation- pulse width modulation) method, because of the stability and reliability. Multiple input and multi-sampling rate theory could transmit the neural signals (high frequency) and other data (low and lower frequency) in simultaneously. The output signal of IFT (end stage of FM Front End) is directly decoupled to the next IF amplifier with LC elements. In the IF amplifier, employed the LC coupling instead of the ceramic filter, to spread the band pass. Two TA7302 are used for the IF amplifier. TA7031P was used for the discriminator. At the results, this improved system could transmit the data by above-mentioned theory, and clearly demodulated the 50kHz pulse train at the receiver. [J Physiol Sci. 2008;58 Suppl:S99]

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Saccadic eye movements, rapid shifts of eye position, were measured in male C57Bl/6 mice using newly developed infrared video-oculography with 500 Hz sampling during head-fixed binocular recordings.The video-oculography is composed of two high-speed digital video modules (max. 1kHz sampling) and a standard PC with a multi-core CPU. A custom built, multi-thread image analysis software enables on-line, simultaneous binocular tracking in a multi-processor computer.Observed saccadic eye movements were generally well-conjugated with sometimes asymmetric amplitudes and directions between both eyes.Repetitive electrical stimulation of the superior colliculus, a major brain area for generating and controlling saccadic eye movements, induced conjugate rapid eye movements similar to the spontaneous saccades. The findings suggest that the mouse, a lateral-eyed rodent, has neuronal machinery for controlling binocularly well-coordinated saccadic eye movements like other frontal eyed mammals. [J Physiol Sci. 2008;58 Suppl:S99]

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'Control center', 'effector', and 'factors' are the main components in the conventional material explaining negative feedback. Changes in the 'factors' are sensed by receptors, 'error messages' are generated in comparison with the 'set point', and based on this, the control center regulates the effectors. In 'Step-by-Step Study of Physiology and Medicine' (http://physiology1.org), the following points were innovated: *Specific explanation is given of changes in activity and factors in the body rather than structure. *Explanation is provided using a model of 'cause' and 'result'. To make the model as simple as possible, a two-layer structure is used. *Changes in activity and factor are clarified. For example, respiration is the 'cause' and depending on this cause, an increase in blood oxygen, which is the 'result' is brought about. When blood oxygen decreases, for reasons other than this mechanism, this would represent a decrease in the 'result' (increased blood oxygen). Then the 'cause' (namely respiration) is increased and the decreased 'result' is brought back to the set point. Likewise, it was confirmed that in all regulatory systems, such as for body temperature, blood pressure and osmotic pressure, the 'cause' and 'result' could be clarified. The actual materials are presented in a step-by-step manner and simple two-choice 'Achievement Quizes' are presented for active learning. [J Physiol Sci. 2008;58 Suppl:S99]

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Many Japanese women complain of severe coldness even in mildly air-conditioned rooms; however, it has been not clarified why they feel colder than others. This study investigated physiological and psychological thermoregulatory responses in young woman. Twelve Japanese female students (mean 21.5 yrs old) were included in this study. To clarify female thermoregulation at mildly low ambient temperature (Ta), we divided the subjects into two groups based on their cold sensation; feeling severe coldness (C group) and not feeling severe coldness (N group) in a mild Ta. We studied two sessions as follows: (1) each subject stayed at a Ta of 29.5 °C for 25 min and then at a Ta of 23.5 °C for 15 min in a thermostatic chamber. (2) Each subject stayed at a Ta of 29.5 °C for 25 min and stayed at a Ta of 29.5 °C for 25 min, although the subject was informed that the room temperature would decrease to 23.5 °C. Each session was conducted at a random order. We measured using a thermocouple at four peripheral parts of their body. Thermal comfort and sensation were evaluated using an18-cm line rating scale. Measurements were conducted for each subject during the follicular phase (FP). Toe temperature in the N group transiently increased after changing Ta; therefore, female thermoregulation was affected by both autonomic function and peripheral skin temperature. The results of autonomic nerve activities evaluated with an electrocardiogram and by Laser-Doppler flowmetry would also be reported. [J Physiol Sci. 2008;58 Suppl:S99]

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Intracerebroventricular (icv) injection of arachidonic acid (AA) in rats evokes biphasic fever, the second phase of which depends on de novo synthesis of cyclooxygenase-2 (COX-2) in brain endothelial cells. To understand the molecular mechanism of AA-induced COX-2, we addressed 2 questions. First, whether does AA itself induce COX-2 or metabolites of AA induce COX-2? AA is known to be metabolized to various bioactive mediators through 3 enzyme pathways, i.e. cyclooxygenase, lipoxygenase, and epoxygenase pathways. None of inhibitors for these 3 enzymes suppressed AA-induced COX-2 induction in brain endothelial cells. This result suggests that AA itself rather than its metabolite induces COX-2 in brain endotheilal cells. Second, whether do fatty acids other than AA induce COX-2? Icv injection of unsaturated fatty acids including oleic acid, linoleic acid, and eicosapentanoic acid induced COX-2 in brain endothelial cells, and evoked fever corresponding to the second phase of AA-fever. On the other hand, lauric acid, a saturated fatty acid, neither induced COX-2 nor evoked fever. These results indicate that COX-2-inducing activity is common to unsaturated fatty acids. It is suggested that AA and other unsaturated fatty acids may facilitate COX-2 induction in various pathological states. [J Physiol Sci. 2008;58 Suppl:S100]

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INTRODUCTION We reported that, in ovariectomized rats, thermoregulation in the cold was attenuated. Systemic administration of 17-βestradiol (E₂) restored the attenuated response. E₂ increased cFOS immunoreactive cells in the medial preoptic area ( MPO ) and dorsomedial hypothalamus ( DMH ) in the cold. In the present study, we hypothesized that E₂ would upregulate thermosensitivity to the cold at the level of the hypothalamus. To test this hypothesis, we assessed the effect of the local administration of E₂ to the two hypothalamic areas on body temperature ( T_b ) in the cold. METHODS Adult female rats were ovariectomized, and a stainless steel canula was placed in the MPO, DMH, or horizontal limb diagonal band. At least 7 days after the surgery, E₂ or cholesterol was administrated to this brain area through the canula. Forty-eight hours after the administration, a rat was exposed to 10°C or 25°C environment for 2h, and T_b was continuously measured. RESULTS During the 10°C exposure, T_b increased only in the group, which is administrated E₂ in the MPO. Either cholesterol nor E₂ in the other brain area had no effect on T_b. CONCLUSION The MPO has abundant estrogen receptors and so-called thermosensitive neurons, estrogen may modulate thermosensitivity to the cold in the MPO. We also clarified the mechanism, based on cFOS immunoreactivity in the hypothalamic areas and UCP1 mRNA expression in the interscapular brown adipose tissue. [J Physiol Sci. 2008;58 Suppl:S100]

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We recently reported that an acute injection of a dual dopamine (DA)/noradrenaline (NA) reuptake inhibitor bupropion improved exercise performance in the heat while providing high brain and abdominal temperature and an increased levels of DA and NA in the preoptic area and anterior hypothalamus (PO/AH) of the rat (Hasegawa et al., 2007). In the present study, we attempted to identify the effects of acute dose of dopamine D₂ receptor agonist quinpirole on brain (T_brain), core (T_core) and tail skin temperature (T_tail) in freely moving rats, and to simultaneously monitor the extracellular DA concentrations in the PO/AH using brain microdialysis. A telemetry device was implanted into the peritoneal cavity and an intracerebral guide was implanted in the left PO/AH for the microdialysis probe. On the day of the experiments, rats received either an intraperitoneal injection of quinpirole (0.1 or 1 mg/kg) or saline (1ml/kg). Both T_brain and T_core significantly decreased after quinpirole (1mg/kg) injection compared with the baseline levels. T_tail, an index of heat loss response, significantly increased after injection of quinpirole (1mg/kg). These thermal changes were accompanied by a significant increase in DA level in the PO/AH. [J Physiol Sci. 2008;58 Suppl:S100]

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We examined the effect of heat exposure on proliferation and differentiation of neuronal progenitor cells in rat hypothalamus. Male Wistar rats, 5 weeks age, were initially maintained at an ambient temperature (Ta) of 24 °C under a 12:12-hour light-dark cycle. Then, heat-exposed rats (HE) were subjected to a constant Ta of 32 °C, while controls were kept at 24 °C. Bromodeoxyuridine (BrdU, 50 mg/kg/day, i.p.) was injected into the rats daily for 5 consecutive days starting on the 1st, 11th or 21st day after commencing heat exposure. Four weeks after termination of BrdU injection, the rats were anesthetized and the brains were sampled. Immunohistochemical analysis showed that in anterior hypothalamus, the numbers of BrdU-immunopositive cells of HE were significantly and consistently greater than those of controls. In HE, 3-4% of BrdU-immunopositive cells were stained by NeuN, a neuron marker, or APC, an oligodendrocyte marker, but rarely stained by GFAP, an astrocyte marker. The majority of BrdU-immunopositive cells were double-stained by doublecortin (70%), a marker of neuronal progenitors which differentiate into neurons. These results suggest that heat exposure facilitates proliferation of neuronal progenitor cells in anterior hypothalamus. Heat exposure also promotes differentiation of newly generated cells which may have a role in functional changes in the thermoregulatory center in heat-acclimated rats. [J Physiol Sci. 2008;58 Suppl:S100]

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Brain serotonin (5-HT) is an important monoaminergic neurotransmitter in the regulation of physiological functions and behaviours, including thermoregulation. The two main sources of 5-HT innervation of the forebrain are the dorsal raphe nucleus (DRN) and the median raphe nucleus (MRN). The physiological function of both nuclei has not been clarified though it is suggested that they have the different roles in the animal behaviour and homeostasis. The present study was designed to compare the role of the DRN and the MRN in thermoregulation of freely moving rats by using microdialysis/biotelemetry techniques. We have already reported that perfusion of tetrodotoxin (TTX) into the MRN induced a decrease in body temperature (Tb) with an increase in increment of heat loss and no change in heat production of freely moving rats (JPS, 57 Suppl.: S185, 2007). Perfusion of TTX into the DRN also induced Tb decrease with the increment of heat loss and change in heat production responses similar to the MRN. These results suggested that the role of 5-HT projection from the DRN and the MRN in thermoregulation mainly is the heat loss system. In addition, it was suggested that there was no functional difference beween these two nuclei in thermoregulation. [J Physiol Sci. 2008;58 Suppl:S101]

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Mammals have autonomic thermoregulatory systems, which induce shivering for thermoregulation. But it is not known when such a system appeared in vertebrates. Here we show that newborn zebrafish has gained an autonomic thermoregulatory system that shakes body and tail fin for thermoregulation. When temperature was lowered from 28.5 ^oC to 9–18 ^oC in newborn fish 3 days post-fertilization (3 dpf), shaking of body and tail fin occurred. In spinalized fish, this response remained intact, indicating that shaking is reflex. To ask whether shaking induces thermogenesis, we measured water temperature (250 μl) in a test tube which was initially held at 12 ^oC and heated by shaking of fish placed in the tube. When five fish were placed, temperature increased by 0.005 ^oC * s⁻¹. When ten fish were placed, temperature increased by 0.010 ^oC * s⁻¹. These results show that cooling-induced shaking induces intensive thermogenesis. To study motor control, we recorded EMG with cell-attached patch mode in spinalized fish embedded in agar. When temperature was decreased from room temperature to 12 ^oC, alternating spikes of right and left muscles occurred continuously below ∼18 ^oC. These spike trains were consistent with shaking in video images, but different from that of swimming. The present study shows the evolutionary path from heterotherms to homeotherms. [J Physiol Sci. 2008;58 Suppl:S101]

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Introduction: Gamma-aminobutyric acid (GABA) is a depressive neurotransmitter, distributed in central nervous system. It has been reported that oral administration of GABA induces antihypertensive effects and a depressing of mental stress at rest. But it is unknown about the effect and the mechanism of GABA oral administration during exercise. We investigated the effect of oral administration of GABA on thermoregulation in man at rest and during exercise and the mechanism underlying this effect. Methods: Eight healthy male subjects drunk a sports drink of 200ml with GABA of 1 g (trial-G) or without GABA (trial-C), rested for 20 min and conducted pedaling exercise of 65% VO2max for 30 min in hot environment (Ta=35°C, RH=40%). We measured esophageal temperature for core temperature, physiological responces. Results: At rest, core temperature (Tes) was slightly increased in trial-C while there was no change in Tes in trial-G. During exercise Tes increased 1.95 ± 0.04 °C in trial-C and 1.79 ± 0.03 °C in trial-G. Increase of blood pressure, heart rate, plasma adrenaline concentration and plasma noradrenaline concentration during exercise were depressed in trial-G compared with those in trial-C. Conclusion: These results suggest that oral administered GABA depressively affects on central thermoregulatory system in hypothalamus and causes the set point shift to the low temperature side. [J Physiol Sci. 2008;58 Suppl:S101]

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We investigated the effects of systemic administrations of ginger (Zingiber officinale Roscoe, Zingiberaceae) and its pungent constituent, [6]-gingerol, on resting body temperature in rats. Rats given ginger-containing rat chow showed no change in day-night cycles of their body temperature and physical activity. However, a single intraperitoneal (i.p.) injection of one of two doses of [6]-gingerol (2.5 or 25 mg/kg) induced a rapid, marked drop in body temperature in a dose-related manner, with no change in physical activity. The significant decreases in metabolic rate was observed immediately after an i.p. injection of [6]-gingerol (25 mg/kg), while heat-loss response underwent no alteration, suggesting that the decrease in metabolic rate is responsible for the [6]-gingerol-induced hypothermia. Thus, [6]-gingerol modulates or interferes with the mechanisms underlying body temperature regulation, while other bioactive constituents of ginger might prevent the [6]-gingerol-induced hypothermia in rats. [J Physiol Sci. 2008;58 Suppl:S101]

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The serotonin (5-hydroxytryptamine; 5-HT) system has been related to many fatigue-associated psychological conditions and the regulation of physiological functions and behaviors (Davis and Bailey, 1997). Previous studies suggested that neurotransmitters in the preoptic area and anterior hypothalamus (PO/AH) are closely related to the regulation of body temperature during exercise (Hasegawa et al., 2005). There is however a need to examine the functional role of the specific neurotransmitters concerned in the thermoregulation during exercise. The purpose of present study was to determine the role of 5-HT in the PO/AH on thermoregulation during exercise in the heat, using a brain microdialysis/biotelemetry method. The rats ran for 120min at speed 10m/min in high ambient temperatures. The selective 5-HT reuptake inhibitor, fluoxetine (1mM or 10mM), or Ringer's solution perfused into the PO/AH during the last 60min of exercise through a microdialysis probe. Microdialysis samples were collected every 20min. Body core temperature (T_core), tail skin temperature and heart rate, the indexes of heat loss and production responses were also measured. Although the extracellular 5-HT in the PO/AH increased, both heat loss and production responses were not significantly affected. Consequently, T_core also did not change. These results suggest that 5-HT in the PO/AH might not be the neurotransmitter involved in thermoregulation during low intensity exercise in the heat. [J Physiol Sci. 2008;58 Suppl:S102]

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We examined the regional sensitivity in temperature sensation and thermal comfort/discomfort. Subjects sitting in a 33°C environment were locally cooled and warmed with water perfused stimulators (270cm²). The water for basal, cooling, and warming conditions was set at 35°C, 25°C, and 42°C respectively. The areas stimulated were the neck, abdomen, hand and sole. Each stimulus lasted 90 s. Temperature sensation and thermal comfort/discomfort of stimulated area and those of whole body were reported by the subjects. At the basal condition just before the local stimulation of each area subjects reported hot and uncomfortable for whole body sensations. At the end of 90 s cooling, subjects reported clear cold sensation for local temperature sensation and no significant difference was observed among those of the four areas. But for local thermal comfort/discomfort at the same time point, depended on the area stimulated. While abdominal cooling produced no pleasant feeling, cooling of the other parts produced clear pleasant sensation. As for local warming, at the end of 90 s stimulation subjects reported hot and uncomfortable sensation and no significant difference was observed among those of the four areas. These results show that humans tend to keep the abdomen warm even during whole body heat exposure. [J Physiol Sci. 2008;58 Suppl:S102]

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In order to investigate thermal and cardiovascular responses during exercise in lower (0500) and higher phases (1700) of core temperature (T_c, five healthy men (23-27 yrs) performed moderate cycle work at thermoneutraliy. We measured T_c and skin temperature, skin blood flow (SkBF), heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressures. Mean arterial pressure (MAP; [SBP+2xDBP]/3) and rate of pressure product (RPP; HR x SBP) calculated. Cutaneous vascular conductance (CVC; SkBF/MAP) was expressed as percentage change from control rest (%CVC_base. Before exercise SkBF, HR and T_c were significantly higher in the evening than in the early morning. However, the circadian effect of cardiovascular responses, RPP, MAP and%CVC_base was masked by muscular work. It is concluded that there are no circadian effects of cardiovascular responses between lower T_c phase and higher T_c phase in the circadian cycle. [J Physiol Sci. 2008;58 Suppl:S102]

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It has been previously demonstrated that the carbon dioxide (CO₂) bathing at 100 ppm could affect thermoregulation through the cutaneous vasodilatation caused by CO₂. The purpose of this study was to investigate the modifying effect of emulsified oil on cutaneous blood flow during CO₂ bathing in humans. Seven healthy young adult men participated in this study. Experimental CO₂ water at 100 ppm was obtained by dissolving the mixture of NaHCO₃ and succinic acid in tap water. After resting for 20 min in the room at 25^oC and 50% RH, the subject was immersed up to the shoulder level for 10 min in experimental bath water at 40^oC in which the emulsified oil (fatty acid esters and nonionic surfactants) was dissolved with a concentration of 10 ppm. Tympanic temperature, cutaneous blood flow on the chest and the forearm (as an immersed area) were recorded continuously. Our main finding was that cutaneous blood flow in the immersed area was significantly greater in the experiments where the emulsified oil was added as compared with the control experiment where the emulsified oil was not added. It was suggested that in 100 ppm CO₂ bathing emulsified oil could enhance the cutaneous vasodilatation induced by CO₂ in human skin. However, the underlying mechanisms remain to be examined. [J Physiol Sci. 2008;58 Suppl:S102]

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Introduction Dehydration attenuates autonomic thermoregulation in the heat such as sweating and skin blood flow in human. Hyperosmolality in the extracellular fluid is thought to be involved in this mechanism. In contrast, behavioral thermoregulation (i.e. heat escape behavior) is augmented after hypertonic saline injection in rats (Nagashima et al., Am J Physiol 2001). However, it remains unknown if human activate behavioral thermoregulation during dehydration. Methods Ten healthy young men participated in the present study. Body and skin temperature were monitored. Rating for thermal sensation and comfort were conducted. After 45 min rest at 27°C, they did 50 min ergometer exercise, which was at the level of 40% peak VO₂ or 15% peak VO₂ at an ambient temperature of 35°C or 24°C, respectively. Subjects returned to the rest at 27°C until body and skin temperature being restored. Ambient temperature was then changed from 22°C to 38°C. Results Body weight decreased by 1.1 ± 0.1% after the exercise at 35°C and 0.2 ± 0.1% at 24°C. Plasma osmolality increased by 6 ± 1 mosmol/kg H₂O at 35°C, but did not change at ∼24°C. Thermal sensation and comfort in the heat were augmented (i.e. feeling hotter and more uncomfortable) after the exercise at 35°C. Conclusion Dehydration increases thermal sensation and comfort in the heat in human, which are closely related to behavioral thermoregulation. [J Physiol Sci. 2008;58 Suppl:S103]

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Many women complain of abdominal pains and lumbago during their menstrual period. In this study, we analyzed the effects of a heat-and-steam generating (HSG) sheet on relieving abdominal and lumbar pains in the menstrual period. The HSG sheet warms the body by evaporating warm steam for five to eight hours and are effective in relieving menorrhalgia; however, the mechanism is unclear. To clarify the mechanism, we observed changes of uterine blood flow and changes of autonomic nerve activities. Subjects were 15 women between 19 and 25 yrs old with a regular menstrual cycle. We applied an HSG sheet to each subject for 5 hrs. We recorded an electrocardiogram and calculated the low (LF) and high (HF) frequency components of the power spectrum of R-R intervals. We measured three skin temperatures in the abdominal area warmed by the HSG sheet, 2 cm above the warmed area and lumbar regions for 5 consecutive hrs. We also measured blood velocity of the uterine artery just before and after warming the abdominal region with an HSG sheet. Measurements were performed twice during the subjects' menstrual periods and follicular phase. Hemodynamics of the uterine artery were not significantly changed before and after warming. Our preliminary examinations suggested that the LF/HF ratio may be higher while the subjects were suffering menorrhalgia than while the subjects were relieved from the pain. [J Physiol Sci. 2008;58 Suppl:S103]

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