Skin pressure affects sweating activity via spinal reflex. It is also observed that the change in body posture may alter sweating function. However, this alteration is explained largely by the spinal mechanism. In the present study, we tested the hypothesis that change in body posture may also affect the higher central mechanism for thermoregulation. Each of 10 young healthy subjects assumed an upright sitting or a supine position for 60 min under a hot environment of ambient temperature at 40°C and relative humidity at 40%. Local sweat rates, tympanic temperature, skin temperatures were recorded. Local sweat rate was measured on forearm, chest and thigh using a ventilated capsule method. Sweat expulsions were identified on the sweat rate curves, and their rate was analyzed for measuring central sudomotor outflow. Mean body temperature was calculated as an index of thermal input to central integrating mechanism. The relationship of the rate of sweat expulsions to mean body temperature indicated that the slope of the regression line was significantly increased following the change of posture from the sitting to the supine position. Meanwhile, the intercept of the regression line for the abscissa was not significantly different. The results suggest that the gain of central integrating mechanism for thermal sweating was altered by the change in body posture. It is assumed that the signals arising from circulatory system or from vestibular system modified the activity of central integrating mechanism. [J Physiol Sci. 2007;57 Suppl:S179]

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We had already observed the ability of sweating reduce after -6 ° head-down bed rest of two weeks, and concluded that dehydration by the increase of urine excretion was a cause. However, it is known that reduces the intra-thoracic wall at the space flight, and a urine excretion is not observed. We investigated the effect of combined -6° head-down bed rest and total body negative or positive pressure on thermoregulatory responses. [J Physiol Sci. 2007;57 Suppl:S179]

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During arousal from hibernation, as body temperature increases by about 20-30 °C toward cenothermia within 1 hr, hamster brain is exposed to an intense oxidation stress. We measured ascorbic acid (AA), reduced glutathione (GSH) and uric acid (UA) in the brain tissue homogenate and brain extracellular fluid (ECF) by using very slow flow (3.5 μL/h) microdialysis technique and HPLC to investigate the interaction between water-soluble antioxidants along the time course of arousal from hibernation. Microdialysis probe was located at unilateral striatum, and perfused with artificial cerebrospinal fluid (aCSF) or aCSF containing 60 μM oxypurinol, a xanthine dehydrogenase/oxidase (XOR) inhibitor. Glucose lacking perfusate had no effect upon the respective decrease, increase and transient increase in ECF levels of AA, GSH and UA observed during arousal from hibernation to cenothermia. Inhibition of XOR activity by reverse dialysis with oxypurinol, itself a free radical scavenger, decreased ECF UA and preserved AA levels in the ECF. GSH level was not affected by this treatment with XOR inhibitor. Local supplementation of ECF antioxidants (AA, GSH and cysteine) had no effect upon the profile of transient increase of ECF UA observed during arousal from hibernation. Free radical production by XOR and disappearance of AA from the ECF continues for at least 2 h after the hamster has attained cenothermia. Results suggest that AA is oxidized by free radical of XOR products and/or by other free radical producing processes activated during the arousing phase of hibernation. [J Physiol Sci. 2007;57 Suppl:S179]

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The hypocoagulation of blood in hibernating animals is attributed to the decrease in platelets and the presence of anticoagulant factors in the blood. However, the mechanisms are still not well understood. Therefore, we examined the parameters related to the blood coagulation in Syrian Hamsters (Mesocricetus auratus) during the hibernation-arousal cycles. In the functional tests of coagulation using plasma, the delay of the activated partial thromboplastin time (APTT) and the prothrombin time (PT) were detected in the hibernating animals. However, heparin was not detected in the plasma, while the decrease of the antithrombin (AT) III, and the low, but significant amounts of the thrombin-antithrombin III complex (TAT) were detected only in the deep hibernating animals, suggesting the activation of the blood clotting system. Meanwhile in the histopathological examination, both the accumulation of many platelets and tiny fibrin clots were observed in the hepatic central veins and sinusoids only in the hibernating animals. Thus, the acceleration of the blood coagulation system, at least partially, may exist behind the hypocoagulation in deep hibernating animals. [J Physiol Sci. 2007;57 Suppl:S179]

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Mammalian hibernators are often regarded as a unique natural model for resistance to ischemia/reperfusion injuries. However, their protective mechanisms against oxidative stress evoked by repeated torpor-arousal cycles are yet to be elucidated. To study the blood antioxidant status during arousal from hibernation in Syrian hamsters, we determined the levels of uric acid (UA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in the blood. The plasma UA level, an in vivo indicator of reactive oxygen species (ROS) generation, showed a significant increase in mid- to late-arousal phase. Concomitant with the increase of UA, both SOD and CAT activities increased transiently in blood during arousal, whereas GPx activity decreased by 50%, as compared with the cenothermic control. We also found that the increased SOD activity was ascribed to the extracellular SOD (EC-SOD). These results suggest that both EC-SOD and CAT may play some roles in the antioxidative defense of hibernating hamsters by scavenging ROS, which evoked by torpor-arousal cycles. [J Physiol Sci. 2007;57 Suppl:S180]

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The accurate measurements of human brain temperatures at physiological conditions have not yet been easy. We tried to measure the human brain temperature change in normal adult volunteers during drinking of cold/warm water and exercises. Noninvasive temperature measurements were done using ¹H magnetic resonance spectroscopy (¹H-MRS) at 3.0T. We could detect a transient temperature fall of about 0.5°C with drinking of cold water (500mL/0°C). After drinking, the brain temperature rose gradually. The brain temperature rose about 0.4°C with drinking of warm water (500mL/53°C). These temperature changes were transient and larger than that by heat loss and gain of cold and warm waters. Therefore, these results show that the human brain temperature is affected by the pharyngeal and esophagus temperatures. The brain temperature change was also detected during light exercise such as knee flexion of 1Hz. The brain temperature rose monotonously about 0.5°C with 30min exercise and fell gradually after the end of exercise. This brain temperature change was larger than that of esophagus. These results indicate that the heat balance in the brain changes during exercise. We could measure the human brain temperature changes at physiological conditions using ¹H-MRS. [J Physiol Sci. 2007;57 Suppl:S180]

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To clarify the effects of the thermal stimulation on physiological responses, we evaluated the temperature, circulatory, hematological and immunological changes in 11 healthy female volunteers before and after taking a stone spa (about 41°C). The subjects took the 15 min stone spa three times with 10min resting intervals, either in the daytime, or in the nighttime. Compared with the baseline value before the stone spas, body temperatures of the depths such as the tympanum and surface temperatures such as the palm, upper hand, and thigh, abruptly increased after the first stone spa, and then maintained it with a gradual increase after the second and third stone spa. Heart rate and PRP gradually increased while blood pressure remained unchanged. Blood glucose concentration after stone spa was lower than before it in the nighttime, but no significant changes. Blood lactic acid concentration after stone spa showed lower levels, especially at nighttime. The rate of lymph cell after stone spa was higher than that before it. Conversely, the rate of granule cell after stone spa was lower than that before it. NK cell activities, measured only in the daytime, tended to increase after a stone spa, but not at significant levels. From the present results it became apparent that the stone spa could easily change the rate of leukocyte in contrast to NK cell activities. These results may suggest that these changes were possibly induced through modulating autonomic nervous functions. [J Physiol Sci. 2007;57 Suppl:S180]

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Behavioral thermoregulation is critical for animals to survive in various ambient temperatures. However, cellular and molecular mechanisms of behavioral thermoregulation are not known. Zebrafish is a small tropical fish. Because body of zebrafish larvae is translucent, neurons of the brain are visible. If larvae exert behavioral thermoregulation, we can investigate cellular and molecular mechanisms of behavioral thermoregulation. In this study, we examined whether 3 dpf (day post-fertilization) larvae perform behavioral thermoregulation. When larvae, reared at 28 °C, were released to a pool of high temperature (32.5–40 °C), they exerted escape behavior. To investigate the involvement of brain in this behavior, decerebration was performed. Decerabrated larvae were alive and provoked tail-beating behavior in response to NMDA, but they did not exert heat-induced escape behavior. To identify a receptor mediating heat-induced escape behavior, we hypothesized that TRP (Transient Receptor Potential) V1 and TRPV4 are candidate receptors. Both TRPV1 and TRPV4 were detected by RT-PCR from 3 dpf larvae. We conclude that zebrafish larvae exert heat-induced escape behavior. [J Physiol Sci. 2007;57 Suppl:S180]

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When ambient temperature is decreased, mammals and birds (endotherms) shiver reflexively to maintain core temperature, whereas reptiles, amphibians or fishes (ectotherms) do not shiver. It is not known, however, when shivering capacity appears in vertebrates. Here we show that shivering capacity appears in newborn fishes. When newborn zebrafish (3 dpf, days postfertilization), reared at 28 ^oC, were released to a pool of low temperature (9-18 ^oC), these fishes shook their bodies vigorously and rhythmically for some seconds. Cooling-induced shaking disappeared in adult fishes. Because newborn fishes do not move forward despite shaking, shaking-released energy should be used for heat production. However, thermogenesis in water is not effective for thermoregulation. Therefore, shivering capacity observed in newborn fishes may be inhibited in adult fishes. When decerebrated, 3 dpf fishes still showed cooling-induced body shaking, indicating that this response is physiological reflex. In convulsion of mammals, uncontrollable electric activity in the brain induces seizure. In fishes, even when decerebrated, cooling-induced shaking occurs. Therefore, cooling-induced shaking of zebrafish is not convulsion. We conclude that shivering capacity appears in fishes, which is the origin of the endothermy in vertebrates. [J Physiol Sci. 2007;57 Suppl:S181]

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The subfornical organ (SFO) that lacks blood-brain barrier has been presumed to one of the fever-related central nuclei, because lesion of the nucleus suppresses elevation of body core temperature following peripheral injection of pyrogens, and further there are receptors for lipolysacchalide and interleukins. The preoptic area and anterior hypothalamus (PO/AH) are very famous as the thermo-center, and there is thermosensitive neurons in the nuclei. However, no evidence demonstrates such property of SFO neurons. Therefore, we investigated effect of thermo-stimulation on spontaneous electrical activities of SFO neurons at slice preparations by using multi-electrodes MEA system, and compared with results of PO/AH neurons. By warm-stimulation from room temperature (23-26^oC) to 40^oC in recording chamber, almost SFO neurons (n = 11/13) were extremely excited from 30-33^oC to 38^oC and conversely inhibited over 39^oC. The responses between 33^oC and 37^oC showed obviously Q₁₀ > 2, indicating warm sensitivity in biology. On the other hand, in the PO/AH, warm sensitive neurons occupied only approximately 30-40% of neurons tested in the present study, as reported by many previous studies . These results suggest that the SFO has thermosensitivity as well as the PO/AH, but the ratio of warm-sensitive neurons is larger than that of the PO/AH that are generally known as thermo-center. [J Physiol Sci. 2007;57 Suppl:S181]

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We investigated the influence of face fanning on autonomic regulation containing tympanic temperature (T_ty) and cardiovascular responses in intermittent exercise in the Kendo protector masked humans. Subjects repeated cycle work (at 185 W) and rest for 42 min in a thermoneutral (28°C and rh; 45%). The subjects underwent trial with fanning in the first half (FFH) or the latter half (FLH) in the experimental period. We measured T_ty, skin blood flow (SkBF), heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressures. Mean arterial pressure (MAP) was calculated as (SBP+2×DBP)/3. Rate of pressure product (RPP) and cutaneous vascular conductance (CVC) calculated HR × SBP and SkBF divided by MAP, respectively. Change of T_ty was significantly different among the trials or with and without the fanning. HR in the FFH was significantly lowered with the fanning, as compared without the fanning. In the FFH, RPP and MAP decreased significantly with the fanning. SkBF during intermittent work was not significantly different, and the CVC between the FFH and the FLH was similar in the two trials. The present results suggest that facial fanning is partially reduced thermal and cardiovascular strains during intermittent-severe work in the masked humans. [J Physiol Sci. 2007;57 Suppl:S181]

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Enormous information has been obtained by the exceptional achievements of molecular and cellular biology in last a half century. Accumulation of data at the higher-level biological structures, such as tissues, organs, and individual creatures, gets behind and broadens the context for that obtained the molecular and cellular levels. Under such auspices, a trial to elucidate mesoscopic-macroscopic subjects based on plentiful nanoscopic-microscopic data is of great potential value. We have constructed a mathematical model of ammonia metabolism in hepatic lobule based on a single-hepatocyte model that consists of the biochemical kinetics of enzymes and transporters. The porto-central axis, which is an elemental structure of the lobule, is defined as the systems biological unit of the liver, and is accordingly modeled. A model including both histological structure and position-specific gene expression of major enzymes largely represents the physiological dynamics of the hepatic lobule in nature. In addition, heterogeneous gene expression is suggested to have evolved to optimize the energy efficiency of ammonia detoxification at the macroscopic level, implying that approaches like this may elucidate how properties at the molecular and cellular levels, such as regulated gene expression, modify higher-level phenomena of multicellular tissue, organs, and individuals. [J Physiol Sci. 2007;57 Suppl:S181]

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The attainment of a critically high core temperature has been proposed as an important factor limiting endurance performance in the heat. We have recently reported that an acute ingestion of a dual dopamine (DA)/noradrenaline (NA) reuptake inhibitor (bupropion) improved time trial performance with a high core temperature and without any change in the subjective sensations of fatigue and thermal stress (2005). We attempted to identify the effects of an acute injection of bupropion on exercise performance, thermal responses and neurotransmitters in the preoptic area and anterior hypothalamus (PO/AH) during exercise in the heat of the rat. A telemetry device was implanted into the peritoneal cavity and two intracerebral guides were implanted, one in the left PO/AH for the microdialysis probe, and one in the right frontal cortex for measuring brain temperature. On the day of the experiments, the animals were exercised at a speed of 26 m/min until exhaustion in a warm environment. Exercise performance was significantly improved by an acute injection of bupropion. The final brain and core temperatures in bupropion were significantly higher than the control. Both NA and DA in the PO/AH increased during exercise in both conditions, being higher in bupropion than control. These results suggest that DA and NA in the PO/AH might be responsible in the increase in exercise performance and body temperature. [J Physiol Sci. 2007;57 Suppl:S182]

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We previously reported that levels of plasma corticosterone of rats in the alternatively changing ambient temperature in a lower range (repeated temperature changes between 4°C and 27°C, each lasting for 1h) were higher than those in the constant low ambient temperature (4°C) at 1, 2, 4 and 10 days after the exposure. It was also reported that levels of corticosterone in the alternatively changing ambient temperature in a higher range (repeated changes between 18°C and 34°C, each lasting for 1h) were higher than those in the constant high ambient temperature (34°C) at day one post-exposure. Frequently changing, but not constant, ambient temperatures may have induced a stronger stress. Furthermore, LPS-induced fever in a group with high level of plasma corticosterone was enhanced. Plasma leukocytes counts and intrinsic LPS concentrations with the alternatively changing ambient temperature in a lower range, constant low ambient temperature and constant 25°C for 2days were determined for the elucidation of the mechanism of enhanced LPS-induced fever. There was no difference between these three groups in either parameters. It was not caused either by increased leukocytes counts nor by increased intrinsic levels of plasma LPS. The aim of the present experiments was to ravel underlying mechanisms of the enhanced LPS-induced fever in animals exposed to stressful ambient temperatures. For this purpose, changes of plasma cytokines such as IL-1β,TNF-α and endogenous plasma endotoxin (LPS) during LPS-induced fevers were monitored in rats 24h and 12h after temperature exposures. [J Physiol Sci. 2007;57 Suppl:S182]

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Brain derived neurotrophic factor (BDNF) has been known as a critical player of neural development, synaptic plasticity and potential rescue factor for neuronal disorders. However, recent studies suggest that BDNF has other potential regulatory role in peripheral tissues: for example, BDNF regulates immune functions through the high affinity receptor of BDNF, TrkB, in some immune tissues and cells. Here we report that BDNF and TrkB-T1, the truncated form of TrkB, also express in white adipose tissue (WAT) and the liver in mice and that the expression dramatically changes in obese mice. In lean C57/BL6 mice, BDNF expressed in the liver but not WAT, while TrkB-T1 expressed in WAT but not the liver. In leptin deficient-obese mice (ob/ob), the expression of BDNF dramatically increased in WAT, whereas the expression of TrkB-T1 increased in the liver. Treatment of lean mice with high fat diet also increased their expression in WAT and the liver. Fractionation of WAT with collagenase revealed that BDNF and TrkB-T1 express in mature adipocytes but not in vascular and other types of cells in WAT. We also found that 3T3-L1 adipocyte expresses BDNF and TrkB-T1. BDNF increased the phosphorylation of Akt, p44/42 MAPK and transcriptional factor FKHR in 3T3-L1 adipocyte. Furthermore, BDNF significantly decreased the gene expression of the atherosclerogenic adipokine PAI-1 in the cells. These results suggest that BDNF and TrkB-T1 play a role in the regulation of metabolism in the liver and WAT in lean and obese mice. [J Physiol Sci. 2007;57 Suppl:S182]

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We analyzed monthly weight records during 30 years in a total of 150 residents who were accommodated by mental disability welfare institution with multiple facilities. IQ of all them were below 30 and the institute roughly managed their meals. In order to omit difference of their heights, Body Mass Indexes (BMI) was calculated from each record. They were divided into 2 groups depending on their applied facilities. One had been from childhood (G-Y) and the other had been accommodated after adult (G-E). Mean age of G-Y linearly increased 1-year-old by 1 year. After 25 -year- old, no clear change was founded in mean BMI of G-Y. Besides, mean age of G-E contained period of fluctuated from linear depending on alternation of new comers. In the period, mean BMI of G-E merely increased. The results suggested that obesity in mental disabilities was not caused on the disability itself but on the other factors. [J Physiol Sci. 2007;57 Suppl:S183]

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INTRODUCTION It is well known that body temperature in female is closely linked with menstrual cycle. We reported that estrogen affects thermal regulation in rats: 1) estrogen is involved in circadian body temperature rhythm; 2) estrogen has an important role in thermal regulation in both the heat and cold. Moreover, in human beings, not a small population of females experiences some troubles in thermoregulation such as hot flash or cold sensation. Estrogen replacement therapy is sometimes effective for the females. In this study, we hypothesized that there would be differences in thermoregulation and thermal sensation, depending of menstruation cycle. METHOSDS and RESULTS Eight female subjects with a regular menstruation participated in this study. Experiments were conducted twice for each subject in follicular (F) and luteal (L) phases, determined by basal body temperature. Experimental condition was 120-min exposure at 23.5°C after a 40-min baseline at 29.5°C. Mean skin temperature decreased and body core temperature increased in both F and L during the 23.5°C exposure. Oxygen consumption also increased in F and L. Based on rating scores for thermal sensation and comfort, L enhanced both coldness and unpleasantness when ambient temperature changed from 29.5°C to 23.5°C. COMCLUSION Although the autonomic thermal regulation seems to be similar between F and L, the menstrual phase may have an influence on thermal sensation or comfort. Estrogen may be involved in this mechanism. [J Physiol Sci. 2007;57 Suppl:S183]

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The aim of the present study was to determine whether the anti-obesity effects of tea catechins (TC) would be associated with the expression of uncoupling protein 1 (UCP1), which is a key protein of thermogenesis in brown adipose tissue (BAT). Five-week-old male SD rats were fed with 35% (w/w) high fat diet (HF) for 5 weeks. Thereafter, the animals were divided into 4 groups: HF, HFTC (HF + 0.5% TC), NF (5% normal fat diet) and NFTC (NF + 0.5% TC). The animals were fed with each diet for 8 weeks. On the final day of the experiment, interscapular BATs and perirenal and epididymal white adipose tissues (WATs) were collected. UCP1 mRNA levels in BATs were quantified by real-time RT-PCR method. BAT weights in NFTC and HFTC groups decreased significantly as compared to those in NF and HF group, respectively. Perirenal WAT weight in NFTC group was significantly lower than that in NF group while no significant difference was observed between HF and HFTC groups. Epididymal WAT weights, however, did not change by TC intake. In NFTC group, UCP1 mRNA level of BAT was significantly higher than that in NF group while the difference between HF and HFTC groups was not significant. In conclusion, TC intake reduced perirenal WAT weight in NFTC group. TC intake also affected UCP1 mRNA expression of BAT in NFTC group. Therefore, the suppressive effects of TC on the body fat accumulation appear to be associated with the function of BAT. [J Physiol Sci. 2007;57 Suppl:S183]

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The purpose of the present study was to examine whether anti-obesity effects of tea catechin (TC) intake are enhanced by the switch from high-fat to normal-fat diet in mildly obese rats. Five-week-old male SD rats were fed with 35% high-fat diet (HF) for 5 weeks, and then with four types of diet: HF, HF supplemented with 0.5% TC (HFTC), 5% normal-fat diet (NF), and NF supplemented with 0.5% TC (NFTC) for 8 weeks. Food intake (FI) and body weight (BW) were daily measured. On the final day of the experiment, perirenal and epididymal white adipose tissues (WATs) were isolated and weighed. Total FI and BW in HFTC and NFTC were not significantly different from HF and NF, respectively. In NFTC, perirenal WAT weight was significantly lower and epididymal WAT weight tended to be lower, as compared with in NF. However, there were no significant differences in the weights between HFTC and HF. Plasma total cholesterol level was significantly lower in NFTC than in NF, while plasma HDL cholesterol level was not different between NFTC and NF. Plasma insulin level was significantly lower in NFTC than in NF although plasma glucose level was not different between NFTC and NF. On the other hand, there were no significant differences in plasma levels of total and HDL cholesterols, insulin and glucose between HFTC and HF. These results suggest that the switch from HF to NF plays an important role in enhancing anti-obesity effects of TC intake. [J Physiol Sci. 2007;57 Suppl:S184]

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We examined the regional difference in temperature sensation and thermal comfort/discomfort. Subjects sitting in a 32-33°C environment were locally cooled and warmed with water perfused stimulators. The areas stimulated were the face, chest, abdmen and thigh. The temperature of water for cooling was 25°C, and that for warming was 42°C. The area of stimulation was 270 cm² and each stimulation lasted 1.5 min. Temperature sensation and thermal comfort/discomfort of stimulated area and those of whole body were reported by the subjects using dials numbered from -10 to 10 (0 : neutral). The setting of the dial procedured a voltage which was continuously recorded. At the basal condition without local stimulation subjects reported hot and uncomfortable for whole body sensation. During local thermal stimulation there is no significant difference in local temperature sensation among the four areas. But for thermal comfort/discomfort, face and abdmen displayed characteristic sensation for cold stimulation. Thermal comfort was strongest for the face by cooling. On the other hand, abdominal cooling produced discomfort even in the hot environment. These results suggest that there is regional difference in the production of thermal comfort/discomfort. [J Physiol Sci. 2007;57 Suppl:S184]

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Cold constitution is a condition in which the patient feels uncomfortably chilly especially the fingers, legs, and waist. The disease persists for more than a half year. Cold constitution might be mainly related to the disorder of autonomic nervous system and a lack of female hormone. Previously, we reported the relationships between the peripheral circulatory function evaluated by the accelerated plethysmogram (APG) and the cold constitution in female students. The females without the cold constitution (Normal group) belonged to the types of good circulation, and higher APG scores. However, there were many females having the poor circulation and lower APG scores in the females with the cold constitution (Cold group), compared with Normal group. In the present study, the relationships between the wave components (a, b, c, d, and e) of APG and the cold constitution were explored in many young female students. First of all, they were divided into both Normal group and Cold group. The Cold group was further divided into three subgroups (weak, medium, and strong) by the severity. We found that the amplitude of wave component "c" of APG in Cold group was significantly greater than that of Normal group. In addition, the amplitude of component "d" of APG in strong Cold group was also significantly greater than that of Normal group. These findings suggest that the peripheral circulatory function in Cold group may deteriorate, when compared with Normal group, because old people tend to have a bigger amplitude of components "c", "d", and "e" in APG. [J Physiol Sci. 2007;57 Suppl:S184]

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Our previous study showed that zinc-deficient mice had lower lick rates for 10-30 mM calcium chloride than did control mice. In this study, we investigated the effects of repletion with dietary zinc and of dissection of the chorda tympani and glossopharyngeal nerves on the ingestion of calcium chloride and sodium chloride solutions in zinc-deprived mice. Behavioral responses were examined by using a 10-s lick test and a 48-h two-bottle choice test between a solution and water. Relative to control mice fed the zinc-replete diet, those fed the zinc-deficient diet had decreased intakes of 0.01 M calcium chloride in both the 10-s and 48-h tests. On the other hand, dietary zinc deficiency increased the intakes of 0.1 M sodium chloride in the 48-h tests, but not in the 10-s tests. When the zinc-deficient mice were fed a zinc-replete diet for 2 weeks, reduced intakes of calcium chloride and increased intakes of sodium chloride disappeared. Both the taste denervated and sham-operated mice, fed the zinc-deficient diet, had lower intakes of 0.01 M calcium chloride and higher intakes of 0.1 M sodium chloride than control mice with intact or sham-operated taste nerves. Thus, the results suggest that unusual intakes of calcium chloride and sodium chloride by the deficient mice are recovered by repletion with dietary zinc for 2 weeks, and that taste information conveyed by the taste nerves does not play an essential role in reduced acceptance of calcium chloride in zinc-deficient mice. [J Physiol Sci. 2007;57 Suppl:S184]

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Zinc deficient rats are known to drink 0.3 M NaCl, avoided by normal animals, in preference to water. We have indicated in the deficient rats that serum sodium has a tendency to decrease and circulating aldosterone significantly increased and suggested that abnormal salt intake reflects increases in sodium appetite. In order to confirm this view, we analyzed angiotensin II in cerebrospinal fluid and serum calcium (involved in the generation of salt appetite) in zinc deficient rats. Animals were given access to either a zinc deficient diet (group 1) or its normal control diet (group 2) ad libitum for one or four weeks. A group 3 was pair-fed with the group 1. Although aldosterone levels were higher in the group 1 than in the group 3, as described in our previous report, angiotensin II levels of both serum and cerebrospinal fluid varied little between these two groups. On the other hand, with the progress of the deficiency, serum calcium concentrations decreased to levels near those of rickets animals. However, there was no significant difference in the calcium levels between the groups 1 and 3 because of the variance within the group 1. These results suggest that unusual salt intakes of zinc deficient rats are mainly due to salt appetite stimulated by a combination of low calcium and high aldosterone in blood. Serum and brain angiotensin II seem not to contribute to the generation of salt appetite of zinc deficient rats. [J Physiol Sci. 2007;57 Suppl:S185]

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We investigated whether green odor inhalation prevents the chronic restraint stress-induced disruption of the skin barrier in rats. Daily 8-h restraint stress for 14 days resulted in an increase in transepidermal water loss (TEWL), an index of the barrier disruption (vehicle+stress group). This effect was prevented by green odor inhalation for 2-h at the beginning of the restraint everyday for 14 days (green odor+stress group). Furthermore, electron microscopic studies revealed that the green odor+stress group has enough inter-corneocyte lipids for an effective skin barrier, that was lost in the vehicle+stress group. On the other hand, daily administration of a glucocorticoiod, dexamethasone (DEX), for 14 days led to an increase in TEWL. Since the green odor reportedly inhibits the stress-induced activation of the hypothalamo-pituitary-adrenocortical (HPA) axis, the present results suggest that chronic stress-induced disruption of the skin barrier is prevented by green odor, through its inhibitory effect on the HPA axis in rats. [J Physiol Sci. 2007;57 Suppl:S185]

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Brain serotonin (5-HT) is an important monoaminergic neurotransmitter and its system has been involved 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 median raphe nucleus (MRN). These raphe nuclei send serotonergic fibers to a variety of fore brain areas such as hypothalamus. We have recently reported that the perfusion of tetrodotoxin (TTX) into the MRN, by using a microdialysis technique, induced a decrease in body temperature (Tb) in freely moving rats (Neuroscience Letters, 306, 126-128, 2001). The present study was designed to determine the mechanism of decrease in Tb after perfusion of TTX into the MRN, by measuring tail skin temperature (Ttail) as an index of heat loss, and heart rate (HR) as indexes of heat production. Tb and HR of freely moving rats were continuous monitored by a telemetry device. Ttail was also continuous measured on the dorsal surface of the skin about 10cm from the tail base using alumel-chromel thermocouple wire. The thermocouple wire was covered with a plastic tube and a metal spring. TTX solution (5μM) was perfused for 60 min into the MRN. [J Physiol Sci. 2007;57 Suppl:S185]

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We investigated the effects of estrogen on insulin signaling in ovariectomized (OVX) rats. Female Wistar rats aged 9 wks were divided randomly into three groups: sham operated (S) group, OVX plus placebo-treated (P) group, and OVX plus estrogen-treated (E) group. The rats in the P or the E group were subcutaneously implanted with placebo or 17β-estradiol (1.5 mg/60-day release) pellets 4 wks after ovariectomy. The experiment was performed 4 wks after the replacement. After 16 hr fasting, the rats were injected with a normal saline with or without 10⁻⁵ M insulin from their portal veins. The liver and the hindlimb skeletal muscle were removed 30 s and 90 s later, respectively. These samples were analyzed for PI3-kinase activity and Akt phosphorylation. In the muscle, insulin-stimulated PI3-kinase activity associated with insulin receptor substrate (IRS)-1 was significantly increased in the E group, but not in the P group. In the liver, insulin-stimulated elevation in IRS-1 related PI3-kinase activity was not observed in either P or E group. There were no significant differences in the amount of IRS-1 and Akt between the three groups. These results suggest that estrogen replacement in OVX rats increases insulin-stimulated PI3-kinase activity associated with IRS-1 in the hindlimb muscle. [J Physiol Sci. 2007;57 Suppl:S185]

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This study was designed to evaluate the effect of aerobic exercise and statin therapy on inflammatory markers in patients (Acute coronary syndrome; ACS) who had undergone successful percutaneous coronary intervention (PCI). Thirty seven male and female patients were studied. All subjects consist of three groups; 1) treated with statin and exercise (SE, n=15), 2) treated only with exercise (EO, n=14), 3) treated only with statin (SO, n=8). For analysis of blood components and body composition, blood collection were performed from subjects before and after experiments, and exercise tolerance test was conducted for ability of motor function. The results indicated that aerobic exercise is able to progress function of heart and improve body composition of ACS patients. And also statin therapy made synergy effect with aerobic exercise. [J Physiol Sci. 2007;57 Suppl:S186]

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Accumulating evidence suggests that higher antibody titers to heat shock proteins (HSPs) are associated with the development and severity of atherosclerosis. The aim of this study was to evaluate the impact of cardiac rehabilitation therapy (CRT) or stain treatment (STT) or a combination of both (COM) on anti-HSP antibodies in patients with coronary artery disease (CAD) after percutaneous coronary intervention (PCI). Clinical evaluation of subjects was performed both at the commencement and completion of the 14 weeks of treatment. CRT consisted of a supervised 6 weeks of exercise following hospital discharge and 8 weeks of home stay exercise. Patients assigned to statin therapy were treated with 80 mg per day of fluvastatin. Blood samples from 39 patients were analyzed for antibodies to HSP60 and HSP70 by ELISA. Biochemical parameters, including lipids, high-sensitivity C reactive protein (hsCRP), and interleukin-6 (IL-6), were also analyzed. We found that CRT and COM reduced antibody titers to HSP60 and HSP70 in CAD patients but statin treatment reduced only antibody titers to HSP70 (by 3.83%). There was a significant correlation between antibody titers to HSP60 versus HSP70. Considering the fact that antibody titers to HSPs are associated with the autoimmune process in CAD, CRT and COM have greater effects on reduction in autoimmune reaction after PCI than statin treatment. This reduction was accompanied by greater improvements in blood biochemical variables, such as lipids, hsCRP, and IL-6 after CRT and COM. [J Physiol Sci. 2007;57 Suppl:S186]

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In our previous study, we presented a significant difference in neuropeptide Y (NPY) mRNA in the arcuate nucleus of the hypothalamus (ARC) between food-restricted and exercising OLETF rats. However, we found no significant differences between ad lib control and exercising rats. It is well known that Golden Syrian Hamsters have a higher activity level than rats and they have strictly distinguished circadian rhythms in running activity. For those reasons, we expected that the regulation factors of appetite behavior will be changed obviously in exercising hamsters. Moreover, hamsters have a hoarding habit, which reflects their long-term appetite. Therefore, we attempted to use the hamsters in this study. As a result, exercising hamsters showed strictly distinguished circadian rhythms in running activity, and we could find the low appetite behaviors indicated by the decreases in eating and hoarding volume of food. Leptin showed a marked decrease in exercising hamsters compared to ad lib controls. No significant difference was found in leptin receptors mRNA in the ARC. Also, in accordance with our expectations, NPY mRNA showed a significant decrease in exercising hamsters compared to ad lib controls. Therefore, we speculate that one of the mechanism leading to exercise-induced appetite inhibition is a decrease in NPY in the ARC. [J Physiol Sci. 2007;57 Suppl:S186]

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We observed time course of changes in pulse wave velocity (PWV) between carotid and femoral arterial sites and augmentation index (AI) of carotid pulse wave in 20 healthy young subjects during cold pressor test and static handgrip exercise. The cold pressor test was performed following Hines-Brown's method, which required subjects to immerse the right hand in chilly water (4 °C) for 2 min. The static handgrip exercise was performed at 30% of maximal voluntary contraction for 2 min. In the cold pressor test, heart rate (HR) increased maximally during 30-60 s period, whereas mean arterial blood pressure (MBP), PWV, and AI increased maximally during 90-120 s period. During static handgrip exercise, MBP, HR, PWV, and AI increased maximally during 90-120 s period, and returned rapidly toward the control value after the end of exercise. While arterial occlusion of the exercising arm was performing at a cuff pressure of 260 mmHg for 2 min immediately after the end of exercise, which maintains muscle metaboreflex, MBP, PWV, and AI sustained significant increases (P<0.01), but HR returned rapidly toward the control value. These changes in PWV and AI were similar to those in muscle sympathetic nerve activities, as reported by Victor et al (1987) and Saito et al (1990). These results suggest that during cold pressor test and static handgrip exercise, not only peripheral artery but also central artery are under vasomotor control mediated by sympathetic nerve activities. [J Physiol Sci. 2007;57 Suppl:S186]

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We developed a new device to measure energy expenditure during walking on uphill and downhill roads. First, we measured oxygen consumption rate (VO₂, respiratory gas analysis) and 3 dimensional acceleration (JD Mate, Kissei Comtec) in 42 middle-aged and older people(63±7(SD) yr) walking on treadmill with graded speed (2–7km/h) while the slope was varied from -15% to +15%. They walked for 3 min at subjectively slow, medial, fast, and fastest speeds for flat and uphill settings and walked at speeds of 3, 4, 5km/h for downhill settings. When the data for last 1min of each speed of walking were pooled, VO₂ (L/min) was highly correlated with the sum of a total impulse (I_total, N·min) and theoretical potential energy gain or loss (ΔPE_g or ΔPE_l, kg·m/min) with a regression equation of VO₂=0.046I_total+0.0014ΔPE_g-0.0006ΔPE_l+0.23 (R²=0.91, P<0.0001). The I_total was determined from a square root of summed accelerations of each direction, and the ΔPE_g or ΔPE_l was from a product of body weight and theoretical height change. Second, to validate the equation, we measured VO₂, I_total, and barometric pressure in 11 of 42 subjects walking on uphill and downhill roads in the field. The height changes were determined from the change in barometric pressure. The VO₂ estimated from the equation (EVO₂) was almost identical to VO₂ by respiratory gas analysis (R²=0.90, P<0.0001) with VO₂=0.91EVO₂+0.1. Thus, energy expenditure during walking on non-flat ground was precisely estimated with this device. [J Physiol Sci. 2007;57 Suppl:S187]

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In this study, we aimed to test the hypothesis that the degree of heterogeneity in the matching of quadriceps microvascular O₂ requirement to O₂ delivery ratio (VO₂/Q) would be lower after prior heavy exercise. Seven healthy male subjects (23.7 ± 5.5 years) performed repeated bouts of 6 min heavy cycle exercise (80% VO_2max). Pulmonary VO₂ was measured breath-by-breath and changes in deoxygenation [deoxy-(Hb+Mb)] were assessed simultaneously at ten different sites of the quadriceps using multi-channel near-infrared spectroscopy. Prior exercise had no significant effect on the time constant of the Phase II VO₂ (Bout 1: 22.7 ± 3.3 vs. Bout 2: 22.2 ± 6.1 s), but reduced the amplitude of the slow component during subsequent heavy exercise. The time constant of deoxy-(Hb+Mb) primary component (τ_p) for bout 1 was faster than for bout 2 (8.6 ± 1.2 vs. 12.1 ± 0.5 s, p < 0.01). The time delay of deoxy-(Hb+Mb) for bout 1 was longer than for bout 2 (12.2 ± 1.2 vs. 9.6 ± 1.3 s, p < 0.01). Prior exercise resulted in a reduction in the dispersion of τ_p of deoxy-(Hb+Mb) (standard deviation of 10 sites, Bout 1: 1.2 vs. Bout 2: 0.5 s). These results suggest that the reduction of the amplitude of the VO₂ slow component during subsequent heavy exercise might be associated with 1) less heterogeneous VO₂/Q and 2) and enhanced muscle O₂ delivery (presumably by the increased and/or faster capillary blood flow), which in turn might have led to decreased recruitment of type II fibers. [J Physiol Sci. 2007;57 Suppl:S187]

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Both exercise and cold stimulation are useful methods to understand the mechanism of increase in blood pressure. The purpose of this study was to investigate the optimum method to produce vasoconstriction selectively in a cold pressure test. Healthy male students served in the following two experiments. 1: In the sitting position at rest, the subject immersed his right fingers in water at a temperature of 19 degrees C. for 1 minute while measuring the blood pressure of the left brachial artery. Fingers, a hand and a forearm were selected as immersing part, and 19, 13, 10 and 6 degrees C. were selected as water temperature. Each cold pressure test was repeated after 5 minutes of interval. 2: In the sitting position at rest, the subject immersed his right hand in water at a temperature of 8 degrees C. for 3 minutes. In the pre-experiment in a middle aged subject, the blood pressure showed 173/113 mmHg by immersion of fingers at water temperature of 6 degrees C. for 1 minute. The blood pressure increased gradually as the temperature became lower, and it was dependent on an increase of calculated peripheral resistance (* stroke volume = mean blood pressure / heart rate). This phenomenon was not remarkable in young subjects. At 2 minutes immersion in water temperature of 8 degrees C., the mean blood pressure increased +10 (7.3-15) mmHg by the increase of vascular resistance without an increase in heart rate. This optimum method of a cold pressure test is useful in the student practice. [J Physiol Sci. 2007;57 Suppl:S187]

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It has recently been reported that time to exhaustion during exercise after aerobic training (AT) and tea catechin (TC) intake was significantly longer than after AT alone in mice. Therefore, we examined the effects of AT and TC intake on endurance capacity and substrate utilization during prolonged exercise (EX) in humans. Fourteen male subjects (23 ± 0 yr; mean ± SE) were divided into TC intake (I; Vo_2peak in ml/min/kg, 51.4 ± 1.3) and placebo groups (P; 49.1 ± 1.9). Subjects in I and P exercised on a cycle ergometer at 60% Vo_2peak for 1 h/day, 3 days/wk, and daily ingested a test beverage containing 584 or 0 mg of TC for 10 wk, respectively. Before and after AT, respiratory gas exchange was measured during 90-min EX at pretraining ∼55% Vo_2peak. After AT, Vo_2peak increased by 16.0% in I and 15.7% in P (P < 0.05), and ventilation threshold (VT) by 24.1% in I and 26.0% in P (P < 0.05), with no significant differences in the changes between both groups. Whole body fat oxidation rate, calculated by indirect calorimetry, increased by ∼18.0% in I throughout 90-min EX (P < 0.05), whereas by ∼13.6% in P only during the first 45 min of EX (P < 0.05). Thus TC intake did not affect the increases in Vo_2peak and VT, but enhanced fat utilization during prolonged EX, possibly contributing to the improvement in exercise performance by sparing muscle glycogen utilization. [J Physiol Sci. 2007;57 Suppl:S187]

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Twelve healthy young adults participated in 50 min basketball game and 120 min resting without cooling-down exercise or 90 min resting with 30 min cooling-down exercise. When these subjects took 120 min rest alone, blood lactate decreased gradually, but urinary bicarbonate and pH began to increase extensively during resting period. When cooling-down exercise was introduced immediately after exercise, blood lactate decreased rapidly to normal levels within 30 minutes, and no increase of urinary bicarbonate and pH was observed for resting period. Such drastic changes in blood lactate and urinary bicarbonate could be explained by the facts that cooling-down exercise enhanced both the oxidative metabolism of lactate and the respiratory rate, resulting in quick discharge of carbon dioxide into expired air from the blood, and finally causing the reduced discharge of bicarbonate into the urine. Without cooling-down exercise, intracellular pH of the circulating erythrocytes was postulated to be acidified, because urinary bicarbonate increased drastically during the resting period. Drastic increase of urinary bicarbonate was explained by the facts that carbon dioxide was metabolized to bicarbonate and hydrogen ion by erythrocytic carbonic anhydrase, and then bicarbonate was discharged from the blood to the urine, resulting the leftover of hydrogen ion in the cells and increased erythrocytic Bohr effects. [J Physiol Sci. 2007;57 Suppl:S188]

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We investigated the effectiveness of resistance exercise (RE) against musculoskeletal dysfunction after 3-week of hindlimb unloading (HU). Female F344 rats (16-week old) were divided at random into the HU (n=6), HU with RE (n=7), and age-matched control (n=6) groups. RE was performed continuously for 30 minutes with an additional load of 50% body mass attached to rat's tail, once a day, 6 days a week. The isometric contractile function and myosin heavy chain (MHC) isoform composition of the soleus were measured. Bone mineral content (BMC) and bone mineral density (BMD) were determined in the whole and in five equally divided regions along the longitudinal axis of the femur from proximal (R1) to distal (R5) regions. The maximum force and force normalized by soleus mass decreased due to HU. Also, the soleus were characterized by the faster contraction and relaxation, and the higher type II isoform composition of MHC after HU. RE ameliorated these changes. HU resulted in significant losses of BMC and BMD of the whole femur. Significant decreases were observed in R2, R4, and R5 for BMC and in R1, R4, and R5 for BMD due to HS. RE slightly prevented losses of BMC and BMD in the whole femur. Interestingly, RE prevented the decreases of BMC and BMD in R5. These results indicated that RE is an effective countermeasure for preventing musculoskeletal dysfunction and that bone responses to HU and/or RE were site-specific. [J Physiol Sci. 2007;57 Suppl:S188]

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To investigate whether immersion of the forearm in water containing high concentration CO₂ (CO₂-water) influences local muscle O₂ consumption (MO₂) and forearm blood flow (BF_muscle) near-infrared spectroscopy (NIRS) was carried out. Six healthy female volunteers (21-22 years) seated in upright position were instrumented on the right lower arm with a laser Doppler flowmetry probe for recording skin blood flow (BF_skin), a NIRS-probe for recording muscle hemoglobin (Hb) contents (oxy-Hb, total-Hb). Blood flow of the forearm was restricted by comprising the inflatable cuff on the upper arm to perform three consecutive venous occlusions (<50 mmHg for 20 s) followed by an arterial occlusion (<280 mmHg, 50 s). MO₂ was determined by evaluating the slope of linear regression line of oxy-Hb decreases during arterial occlusion, and BF_muscle was determined by the rate of increase of total-Hb during venous occlusion. Bath water (30°C) exchanged for another, i.e. tap water (CO₂<20 ppm) into CO₂ water (860-990 ppm) or vice versa, every about 20 min. All subjects reported that CO₂-water was warmer than the tap water. The BF_skin was significantly 3.6 times larger during CO₂-water immersion than tap water immersion. MO₂ and BF_muscle during CO₂-water immersion was respectively 15% and 32% larger than during tap-water immersion. Results suggest that the artificial CO₂-water bathing may increase muscle-blood flow as well as skin blood flow and stimulate the muscle metabolism. [J Physiol Sci. 2007;57 Suppl:S188]

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Previous study of walking includes a lot of biomechanics research evidence and electromyographic (EMG) discuss, and there were various knowledge of physiological experience. However, many of EMG reports were differential walking physical environments and changes of walking speed at forward, backward studies were few. The aim of this study was to investigate EMG activity during various speed of walking and to different each speed of forward (FW) and backward walking (BW). Eight subjects participated in this experience after informed consent that walked forward and backward each 5 minute in order of three different speeds; 2, 4, 6 km per hour on the treadmill, while there motion, ground contact information, and EMG activity from follow muscles (elector spinae, gluteus maximus, rectus femoris, vastus medialis, biceps femoris, tibiralis anterior, medial gastrocnemius, and soleus) were recorded. The EMG data rectified all waves, and calculated the integrated EMG (iEMG). Furthermore iEMG was normalized of FW at 2km per hour. Statistical processing used one way repeated measures of ANOVA (= 0.05). EMG activity has increased with the rise of walking speed. Comparison of FW and BW at the same speed, especially TA muscle activity was significantly high value than FW. Consequently, EMG activity of BW was different from FW and selectively active. Meanwhile Sol muscle activity was an insignificant effect in all test. It was consider that muscle atrophy of aging was prevented on BW, and could apply one of the training for aged person. [J Physiol Sci. 2007;57 Suppl:S188]

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The purpose of this study was to determine the effects of initial hydration status and core temperature on endurance capacity in untrained individuals during heavy exercise in a hot environment. In addition, we also examined the final core temperature at exhaustion in untrained individuals. Untrained subjects (n=6) performed three cycle exercise trials at 80% VO₂max until exhaustion in a climatic chamber (32°C, 60% RH) under the following three conditions: 1) 2% hypohydration + 38.2°C rectal temperature; H2, 2) 1% hypohydration + 37.8°C rectal temperature; H1, 3) euhydration + 37.6°C rectal temperature; EU. Before each exercise trial, subjects performed 100 min of exercise in which their hydration status and core temperature were altered. Exercise tolerance time averaged 7.7±1.5, 14.0±2.4, and 20.9±3.7 min during H2, H1, and EU, respectively; a significant difference was found only between H2 and EU. Subjects reached exhaustion at a consistent final rectal temperature of 38.4±0.1°C regardless of those trials. Exercise tolerance time was strongly related to the initial levels of rectal and mean body temperatures and the increases in rectal, mean skin, and mean body temperatures during exercise. It is concluded that hypohydration-induced higher initial core temperature have a detrimental effect on endurance capacity in untrained individuals during heavy exercise in a hot environment. [J Physiol Sci. 2007;57 Suppl:S189]

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To test the effectiveness of centrifuge-induced artificial gravity with ergometric exercise, 12 healthy young men were exposed to simulated microgravity for 20 days of head-down bedrest. Half the subjects were randomly selected and loaded 1.2 G artificial gravity with 60 W of ergometric workload everyday(CM group). The rest of the subjects served as the control. Anti-G score, defined as the G-load; running time to the endpoint, was significantly elongated by the load of the centrifuge-ergometer. Centrifuge-induced artificial gravity with exercise is effective in preventing cardiovascular deconditioning due to microgravity exposure, however, an effective and appropriate regimen (magnitude of G-load and exercise workload) should be determined in future studies. [J Physiol Sci. 2007;57 Suppl:S189]

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We examined the effect of lumbar warming on thermoregulatory responses in six elderly subjects (age 63-75y, mean b. w. 55.2kg) using a commercially available steaming pad (12x20cm, Kao Corp.) that can generate steam heat to raise local skin temperature up to 40C more than 5 h. After outfit of thermocouples on skin (10 points) and two ventilating capsules for perspiration (Perspiration meter SKD-2000, SKINOS) along with adjacent attachment of two probes of a laser Doppler flowmeter (Advance Laser Flowmeter, ALF21RD, Advance Co, Ltd.) on chest and back, each subject wearing hospital pajamas sits on chair for 15 min (control) followed by outfitting the pad on lower back region and then maintained it for another 60 min in thermoneutral environment (25C, 45%RH). Each skin region had different thermal response. After lumbar warming, the local skin temperature of foot, toe, hand, chest, back rose significantly, whereas that of leg fell by 1.9 and forehead also fell by 0.4 degree. Temperature of tympanic membrane was unchanged. Blood pressure and heart rate did not change significantly. Sweating was observed in three subjects and skin blood flow in adjacent region was simultaneously increased. All subjects reported feeling of warmth with great comfort during lumbar warming except chilly sensation at leg and thigh. These results suggest that thermal responses of the overall skin to lumbar warming may vary depending on body region, time course of warming and individual characteristics in regional circulation. [J Physiol Sci. 2007;57 Suppl:S189]

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We observed heart rate (HR), mean blood pressure (MAP), sweating rate (SR), and skin blood flow (SkBF) responses to mental task under different ambient temperatures (Ta), i.e., 12, 16, 20, and 24 °C. Seven subjects (27 ± 5 yrs, 64 ± 14 kg) underwent 2-min color word conflict test (CWT) after 2 minutes of data acquisition to establish a baseline following a 15-min resting period. All subjects wore long sleeve shirts and long pants. The SkBF was measured with a laser Doppler probe on the left index finger pulp, and the SR was measured with a ventilated capsule on the left thenar. Minute-by-minute data were calculated. CWT significantly increased the HR and MAP, while there was no significant effect of Ta on the magnitudes of these responses. CWT significantly decreased the SkBF when the Ta was 20 or 24 °C, whereas it significantly increased the SkBF when the Ta was 12 or 16 °C. SR was significantly increased by CWT, and it was significantly greater under 24 °C than under 12 and 16 °C conditions. These findings suggest that different ambient temperatures induce different finger skin blood flow responses to mental task, implying the independent nature of cutaneous vasomotor tone and sweat gland in glabrous skin. [J Physiol Sci. 2007;57 Suppl:S189]

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Introduction & Methods: We have reported that magnitude of reduction in arterial pressure at a level of the brainstem (APLB) is greater after stop of the anti-G suit operation than before start of the anti-G operation when exposed head-to-tail G by a centrifuge. To clarify the cause of the greater hypotension after stop of the anti-G suit operation, anesthetized male Sprague-Dawley rats were exposed to acceleration (3 and 5G). APLB, arterial pressure at a level of the lower body (APLL), central venous pressure, ECG, and aortic blood flow (AoBF) were measured. Peripheral vascular resistance (PVR) was calculated. Results: APLB was kept to the control level during inflation of an anti-G suit. However, hypotension was observed in G-increasing and -decreasing phases, and a significant difference was found between them. In the APLL, definite hypotension was observed only after inflation of the anti-G suit. AoBF and resultant PVR significantly decreased after than before the inflation (33.4±11.7 vs. 41.2±16.3 ml·min⁻¹ and 0.98±0.45 vs. 1.15±0.42 mmHg·min·ml⁻¹ ). Conclusion: No significant difference was found in the internal pressure of the anti-G suit or in loaded G between before and after the anti-G operation, but significant decrease was found in APLL and PVR after the anti-G operation, the vasoconstring responses to G loads should be suppressed. These results indicated that an anti-G suit might induce decline of peripheral vascular resistance after G loads. [J Physiol Sci. 2007;57 Suppl:S190]

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We have previously reported that anxiety increases body sway in college students during orthostatic standing (Wada et al, 2001; Ohno et al., 2004). In the present experiment, relationship between the body sway and the degree of anxiety was explored in 11 healthy participants while standing with a visual target changing in size. The size of visual target continuously varied between 5.34° and 8° in visual angle with a frequency of 0.3 Hz. Body sway recorded was computed by FFT analysis, and the power of the four frequency bands (0.02-0.1 Hz, 0.1-0.21 Hz, 0.21-1 Hz and 1-10 Hz) were calculated on the basis of frequency properties of sensory inputs affecting postural balance. A negative correlation between the degree of anxiety and the power of the frequency band of 0.1-0.21 Hz in the left-right axis of body sway was found to be statistically significant (r= -0.68, p<0.05). No correlation was found between anxiety and any of the frequency powers in participants with a stable target with visual angle of 8°. It has been postulated that sensory inputs from the vestibular organs stabilizes the body sway with 0.1-0.21 Hz (Redfern et al., 2001). Therefore, the present result has raised a possibility that anxiety increases the recruitment of vestibular inputs to maintain the postural balance when the visual angle is periodically changing. [J Physiol Sci. 2007;57 Suppl:S190]

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A correlation between anxiety and postural instability is suspected in anxious patients. However, the results of preceding studies exploring the correlation between anxiety and postural balance in healthy populations are controversial. We have employed FFT analysis of body sway during orthostatic standing while gazing at a visual target in college students, physically and mentally healthy. The influence of anxiety was found in frequency components of 0.02-0.21 Hz and 2.02-10.0 Hz. Frequency components of 0.02-0.21 Hz, reflecting vestibular inputs, were 16% greater and those of 2.02-10.0 Hz, reflecting somatosensory inputs, were 24% smaller in high anxiety group. The influence of anxiety was abolished when the eyes were closed. We have further explored the correlation between anxiety and the postural control in healthy college students employing a within-subject design. Body sway during orthostatic standing and state anxiety on the day of experiment were measured twice with an interval of 1 month. Results have shown that the length of antero-posterior bodyy sway and the enveloped area of body sway are positively correlated with anxiety. These correlations were not observed when the eyes were closed. Our studies have been concluded that anxiety affects the information processing of sensory inputs essential for the postural control and causes an instability of the standing posture. [J Physiol Sci. 2007;57 Suppl:S190]

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The CEEF, Closed Ecology Experiment Facilities, is a system for studying propagation and accumulation of 14C released from a reprocessing site of spent nuclear fuel. The facilities are designed to regenerate everything required for living, such as air, water, and food. Researchers responsible for operating life support systems in CEEF, designated as econauts, play a crucial role in maintaining the system in good order. Artificial environments such as CEEF must involve confinement, which is one of the major factors responsible for deterioration in crew health and performance in space or other analogous situations, such as bases in Antarctica. This is the first trial in which people with a certain level of aptitude relevant to astronaut selection repeatedly inhabited a confined facility as researchers. In this research, 7-day habitation was repeated six times. Blood samples were taken from econauts before and after each period of habitation and analyzed for leukocyte ratio by flow cytometric assay. Psychological scale was surveyed using the face scale test. Although some trends were seen in changes of leukocyte ratio, no marked clinical changes were observed in the econauts. These data are essential in considering the effects of forthcoming long-term habitation in CEEF. This report includes a part of the results from research conducted under contract with Aomori Prefectural Government, Japan. [J Physiol Sci. 2007;57 Suppl:S190]

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In the present study, we examined the effect of hyperoxia on skin vasomotor and sudomotor responses in heat-stressed human. Eleven healthy male subjects breathed 21% (room air) or 100% O₂ during normothermia and heat stress produced by hot water-perfused suits. Skin blood flow (SkBF) in forearm was monitored by laser-Doppler flowmetry. Cutaneous vascular conductance (CVC) was calculated as the ratio of SkBF to blood pressure. Local sweating rate (SR) in forearm was monitored by ventilated capsule method. Breathing 100% O₂ increased (P<0.001) arterial O₂ saturation during normothermia and heat stress, while end-tidal CO₂ was maintained at a constant level throughout the O₂ inhalation in the two thermal conditions. Breathing 100% O₂ did not alter core or skin temperatures. Breathing 100% O₂ decreased (P<0.05) CVC under normothermic and heat-stressed conditions. Blockade of adrenergic vasoconstrictor function by using bretylium (BT) iontophoresis did not diminish the reduction of CVC during 100% O₂ breathing under the two thermal conditions. The hyperoxia-induced reductions in CVC did not statistically differ between the BT-treated and untreated sites. Breathing 100% O₂ did not change SR from the normoxic baseline level. From these findings, it was suggested that hyperoxia induces skin vasoconstriction via non-adrenergic mechanisms but does not alter sudomotor activity. [J Physiol Sci. 2007;57 Suppl:S191]

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Changes of body fluid distribution in response to the levels and/or direction of gravity, created by the parabolic flight of a jet airplane, were investigated in 5 healthy male subjects. Distribution of body fluid was estimated by using the impedance plethysmography. Electrodes were placed around the chest, abdominal, thigh, and calf regions. The gravity levels were altered from 1- to 1.8-G during the ascending phase and then μ-G was created for ∼23 sec. The recordings were performed in each subject with sitting, upright standing using both feet, and horizontal positions. For sitting position, the subject maintained the knee either at ∼120° on a seat or fully extended on a bed. Recordings were also performed at both supine and prone positions on a bed keeping their head toward either the nose or rear of the airplane. The greatest shift of fluid toward lower limbs was noted when the standing subjects were exposed to 1.8-G, and the shift was reversed toward the upper body at μ-G. Similar shifts were observed in sitting position on a seat, even though the magnitude was minor. Profound shift was not induced when the subjects were sitting on a bed. Further, slight, but significant, shift from the upper body toward lower extremity was seen in μ-G environment, when the subjects were at horizontal position keeping their head toward the nose of the airplane, or vice versa. These results suggest that body fluid clearly shifts toward upper body when the Gz gravity becomes zero. [J Physiol Sci. 2007;57 Suppl:S191]

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Neonates sometimes suffer from severe brain damage by hypoxic-ischemic (HI) insults such as cord compression during delivery. Brain hypothermia soon after the HI insult might relieve HI encephalopathy (HIE) but this has not been fully examined. In this study, the effect of brain hypothermia was examined using a simple behavioral method. For the study of neonatal HIE, rat HIE models were produced by ligation of the left or right carotid artery in 7-day-old rats followed by exposure to a hypoxic environment of 8% oxygen for 15 minutes. We made five groups of rats; NRG (n=8) and NLG (n=7) groups had the right and left carotid artery ligated, respectively, and were returned to their mother. HRG (n=6) and HLG (n=6) groups were placed in hypothermic conditions of 33 °C for 12 hr after right or left carotid ligation. A sham group (SG, n=3) was also established. We performed a swimming test using 4- to 7-week-old rats. The rat was placed in the center of a circlular pool (diameter 150cm, depth 15cm) and swam in a clockwise or counterclockwise direction until it arrived at the pool wall. NLG tended to turn counterclockwise, but NRG tended to turn clockwise. However, SG, HLG and HRG tended to turn equally clockwise and counterclockwise. The ratios of operated/contralateral cerebrum hemisphere were 1.00, 0.87, 0.81, 1.00, 0.94 in SG, NLG, NRG, HLG and HRG, respectively. Brain hypothermia soon after HI insult may improve physical function in HIE rats. [J Physiol Sci. 2007;57 Suppl:S191]

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The ambient temperature (Ta) of the delivery room has been under discussion because high Ta is suspected to relate to neonatal encephalopathy, but not so well clarified. We investigated the effect of Ta on the learning ability of an adult rat model after neonatal hypoxic-ischemic (HI) insult. Under inspired anesthesia, the left carotid artery of a 7-day-old rat was ligated, and followed by a hypoxic insult made by delivering 8% oxygen at 40 °C for 15 min. The rats were returned to their mother for 1 hr, and then placed in a box of one of three Ta of 40 °C (n=7; high Ta group, HG), 38 °C (n=7; normal Ta group, NG) and 33 °C (n=7; low Ta group, LG). A sham group (n=5; SG) was also established. Three months after the operation, the learning ability of the rats was assessed using a step-down passive avoidance test. On the first day of the measurement, the rat was placed on an insulated rubber platform of 5 cm in diameter on a metal floor. Once the rat stepped onto the metal floor, the rat experienced discomfort via an electrical foot shock. The interval of the rat moving from the rubber to the metal floor was measured for five successive days. The test was performed once a day. On the last day, SG, LG, NG and HG rats stayed on the rubber floor for 600, 585, 40 and 20 sec, respectively. This result indicates that higher Ta after HI insult may result in restricted learning ability after growth. [J Physiol Sci. 2007;57 Suppl:S191]

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