Capsaicin has been known to produce a hypothermia in the adult animal, probably by its action on the warm-detectors responsible for thermoregulation. The effect of capsaicin on the body temperature was studied in the new-born rats aged 6 hours to 5 days old. Under ether anesthesia, a stainless-steel guide cannula (0.5mm, o.d.) was subacutely implanted into the brain, aimed more or less at the preoptic area and anterior hypothalamus (PO/AH) . The animals were held in a prone position on a sponge rubber mat in a‘neutral’ enviroment where the animal could maintain the rectal temperature (T_re) at 36-37°C. The subcutaneous injection of capsaicin (5-10μg) produced a sudden fall in T_re (1-2°C) . With repeated injections of increasing doses, the hypothermia diminished progressively and finally the animal became completely unresponsive to a large amount (1mg) of the drug (desensitization) . Direct injection of capsaicin (5μg) into PO/AH also produced a prompt fall in T_re even in 1 dayold rats and the repeated injection resulted in the diminished responses. The injection outside PO/AH or the injection of solvent alone had no effect. Since the PO/AH warm-sensitive neurons in the new-born rat specifically respond to capsaicin, it is suggested that the capsaicin-induced hypothermia is brought about, at least in part, by its action on the PO/AH warm-sensitive neurons. These results indicate that the neonatal PO/AH warm-sensitive neurons attain some degree of maturity to respond to capsaicin, to lower the body temperature and to be desensitized by capsaicin.

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How does the LPS-pyrogen act on the nervous system was analyzed by the Limulus test (pyrogen test) for endotoxin in blood plasma. A cell lysate prepared from amoebocytes of Limulus polyphemus is an extremely sensitive indicator for the presence of endotoxin (LPS-pyrogen) . The state or grade of gelation reaction characteristic of a quantity of endotoxin in plasma is dependent on the concentration of clottable protein in the amoebocyte lysate and endotoxin in the assay mixture. In intact rabbits, gelation reaction for endotoxin in blood plasma during fever induced by LPS-pyrogen injected intravenously was gradually diminished in the time course, though higher temperature in rectum was still kept. And the simultaneous detection of endotoxin in the liquor in central nervous system, the result of the gelation reaction was almost negative. On the contrary, gelation reaction tested in liquor during high fever induced by the lateral ventricular as well as by the subdural administration of LPS-pyrogen was strong positive, but was almost negative in blood plasma. These results suggest that LPS-pyrogen has a strong effect directly on the central thermoregulatory mechanism if it is administered in central nervous system, but LPS-pyrogen itself does not pass through the blood brain barrier. The first and the second peak of the biphasic response to intravenous or intraventricular administration of LPS-pyrogen might be mediated by both exogenous and endogenous pyrogen which were discussed from the results in the present investigation.

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Central nervous interactions between baroreceptor and chemoreceptor control mechanisms were studied by many researchers (reviewed by Iriki and Korner, 1979) . But the central interaction between baroreceptor control and thermoregulation has not yet been investigated precisely, in spite of the precise investigation about the responses of regional circulation and of undergoing regional sympathetic nervous activities to thermal stimulations. This experimental series was aimed to elucidate the central interaction of circulatory and thermal regulatory mechanisms.
Methods: Renal sympathetic nerve activity (RSNA) of unanesthetized rabbits was recorded using chronically implanted electrode. The integrated activities in every 2 seconds, simultnaeously recorded with direct recording, were used for the indicator of the RSNA. The mean arterial pressure (MAP) was elevated or fallen 5, 10 and 20 mmHg from resting MAP by means of previously implanted aortic and vena caval perivascular balloons. Rectal and ear temperatures were recorded simultaneously.
The RSNA baroreflex curve was estimated by the response of RSNA to the change of MAP in neutral (25°C), cold (15°C) and warm (35°C) environments. The condition of cold environments was selected when the ear cutaneous vessels were constricted but no shivering could be detected, and in warm environments the ear cutaneous vessels were markedly dilated but no significant increase of respiratory rate (panting) was presented. Renal sympathetic baroreflex functions in various conditions were compared by the calculating of median arterial pressure, RSNA range and reflex gain of the renal baroreflex curves.
Results and discussions: Within the zone of vasomotor control of physical thermoregulation, i. e. the zone without shivering or panting, the resting MAP in warm environments was lower than that of cold, and no signifcant difference of RSNA at resting MAP at both conditions could be detected. Concerning the parameters of RSNA baroreflex curves, all three curve parameters in warm condition were significantly lower than those in cold. That means the existence of significant central interaction on renal sympathetic motoneuron pool between baroceptor inputs and thermal inputs. Warm receptor inputs have inhibitory effect on the central interaction.
When the panting was presented in hot environments, the central interaction of both inputs on the baroreflex control of RSNA was also significant, but its direction was contraverse to those in warm environments without panting. It could be clarified by the increase of all three curve parameters in hot comparing those in cold.

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Occurrence of thermal sweating in response to heat exposure was examined on 4 to 8 areas of different regions of the subject assuming various postures either by the iodine-starch paper method or by continuous sweat-rate recording using resistance hygrometry. Thermal load was given either by placing the subject in the climate chamber of a constant temperature of 38°C with the relative humidity of 40%, or by raising the room temperature from 26°C at a rate of 0.2°C/min.
In the upright or sitting position, sweating on all the test areas generally occurred almost simultaneously or within several minutes of one another. On the other hand, in the supine position, the onset of sweating was delayed markedly in the test areas of the upper half of the body. Furthermore, with the subject lying on one side, sweating appeared on that side much later than on the other side. Pressure application to a specified area affected regional differences in the occurrence of sweating similarly to postural effects. From these observations, it was concluded that the pressure-sweating reflex initiated by various postures exerts decisive effects on regional differences in the occurrence of thermal sweating. The extent of the region where sweating was suppressed ref lexly by pressure application to the lateral chest shifted as the level of the pressure site moved, suggesting this reflex has dermatomal effects involving the segments where afferent volleys cuased by skin pressure enter the spinal cord.
Skin temperatures at different areas did not vary so greatly, as they would exert significant effects on regional differences in the initiation of thermal sweating. However, greater changes in local skin temperature produced by leg immersion in warm bath definitely affected the initiation of the local sweating.
The onset of sweating in an area with relatively low sweat-secretory capacity tended to be delayed to some but not a great extent.

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A model with regard to wet heat loss from skin surface was made taken the effect of humidity on thermal sensation into consideration. The present model is consisted of two control regions an—environmental region where the rate of moisture exceeds the maximum environmental capacity to accept evaporated moisture and an environmental region where the rate of moisture is less than the environmental capacity. We call the former region I and the latter region II.
In region I, by applying and developing wettedness model by Gagge et al with regard to skin evaporation, the evaporative heat loss in this region is given by the following equation.
H_e=κh_c (Ψ_sX_ss-X_a) W
where, H_e: wet heat loss from skin surface
κ: modified Lewis relation
h_c: convective heat transfer coefficient for the human body
Ψ_s: percentage humidity at skin surface
X_ss: saturated humidity ratio at skin temperature
X_a: humidity ratio in ambient air
W: wettedness by Gagge et al
Although percentage humidity Ψ_sfor the boundary layer at skin surface is always unity in wettedness model, that in the present model is assumed to be not always unity and to have close relationship to environment humidity. As a consequence of surveying from clothing worn, air movement and so forth, we obtained a relation between percentage humidity at skin surface and that in ambient air.
In region II, man's ability to squeeze out the moisture is assumed to have a certain limit. A moisture control center regulates the quantity of moisture and wet heat loss is given by the following equation.
H_e=G⋅L
where, G: quantity of moisture (insensible perspiration and sweat secretion, at comfort condition, only insensible perspiration)
L: latent heat
Heat balance between man and his environment is expressed by considering four main heat loss terms in a steady state—radiation, convection, evaporation and respiration. Based on the rational heat balance equation derived, a comfort chart was proposed as an index of comfortable sensation and for enviromental assessment and the proposed comfort line was compared with experimental data and theoretically derived comfort lines by earlier workers.

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Body temperatures were measured during exercise on bicycle ergometer (24.5 W-98.0 W) in experimental conditions in which no sweating was observed.
1. During 10 min exercise at 26°C, skin temperatures on the hand, forearm and chest fell with increase in work intensities (49.0 W-98.0 W) . Increased metabolic activities were accompanied by increased surface areas of lowered skin temperatures.
2. During 1 hr exercise at 10°C, the rectal temperature rose in proportion to work intensities (49.0 W-98.0 W), but the mean skin temperature remained unchanged. After the cessation of exercise, the mean skin temperature showed a transient rise.
These findings may suggest the possibillity that the thermoregulatory vasodilator caused by increaed heat production in exercise is counterbalanced by the vasoconstriction caused by nonthermal factors of unknown origin.

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Vascular hunting reaction was observed on 20 young male university students born and raised in the Japan Main Island, temperate zone (group M) and 5 young male unversity students born and raised in Okinawa, subtropical zone, but moved to the Japan Main Island in less than three years (group O) . Whole body cold tolerance test were made on 15 subjects in group M and 5 subjects in group O. Two series of experiments were performed in Nishinomiya. The first series of experiments was performed in July on subjects in groups M and subjects in group O before returning to Okinawa (experiment B) . The second series of experiments was performed in September on subjects in group O after a month's stay in Okinawa in August (experiment A) . Vascular hunting reaction was observed by dipping left middle finger with a thermocouple attached to the nail bed into stirring ice water for 30 min. and changes in skin temperature were measured continuously. Whole body cold tolerance test was performed on the subjects clothed with 1.8 clo by taking off a blanket after covering with a blanket in the supine position in a room of 10°C with 70% R.H. and wind velocity of 17 cm/sec. Physiological responses of the subjects to cold were observed for 60 min. Skin temperatures at 6 sites were recorded continuosly during cold exposure and metabolic rates were measured at 30 and 60 min. In experiment B, group O showed slightly higher mean skin temperature, higher temperature of first rise after immersion and significantly longer time for first temperature rise after immersion than group M. In experiment A, group O showed considerably higher mean skin temperature, higher temperature for first rise and significantly longer time for first rise than groups M and O in experiment B. Vascular hunting reaction of subtropical natives was characterized with long latent time for hunting reaction in spite of essentially the same level of skin temperature and latent time was lengthened after returning to Okinawa. In experiment B, group O showed slightly smaller drop in skin temperature and greater increase in metabolic rate at the end of experiment than proup M. In experiment A, group O showed considerably lesser drop in skin temperature, significantly greater increase in metabolic rate and greater frequency of shivering at 30 min. after cold exposure when compared with those in groups M and 0 in experiment B. Thus, cold tolerance of subjects in group O was reduced by returning to Okinawa in summer.

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Interested in the influences of wind on human body under exercise, the present authors had prepared a handmade wind tunnel with air conditionning and studied some physiological reactions under wind.
Five healthy male subjects (aged 22-24 yrs.) were loaded with a bicycle ergometer work at the rate of 600 kpm/min for 30 minutes, under three different wind velocities (no wind: W₀, 3.8m/sec: W₁ and 5.7 m/sec: W₂), with an air conditionning of temperature: 24°C, relative humidity: 60%.
Following results were obtained:
1) Heart rate decreased by wind (at W₀: 128, W₁: 121 and W₂: 120 beats/min) ; but oxygen intake remained constant (1.5-1.6l/min) .
2) Mean skin temperature kept a certain level rather lower under wind and the change of rectal temperature was not observed.
3) Total sweat rate and local sweat rate showed a decrease by wind, but Na and Cl concentrations in sweat did not change, though there were individual differences.
4) Heat Tolerance Index (HTI) decreased under wind.
5) Under wind, the heat loss by evaporation and convection decreased double and that by radiation decreased to about 1/3 compared with the no wind conditions.

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Electrocardiographic changes in thirty men of 16th Japanese Antarctic Expedition (JARE-16) were studied during the wintering at Syowa Station from February 1975 to January 1976. They were men in good health with average age of 31.0 and a range of 24 to 45. Electrocardiograms were recorded before, after and one year at Syowa Station (February, May and July 1975) . Heart rates, QRS voltage of the precordial leads (SV1+RV5) and electrical axis of the QRS were analysed. Body weights, skinfold thicknesses and blood pressures were measured and hematological examinateions were performed.
Long term changes in physical work capacity in 21 men of 17th JARE were studied during the wintering from February 1976 to January 1977. All were in good health with an average age of 32 years and a range of 24 to 54. Physical examinations and physical performance tests were done in March, June, September and December 1976.
1) Sinus bradycardia was observed in two subjects and first degree A-V block in one subject before, during and after the wintering. Supraventricular and ventricular premature contractions were detected respectively in one subject only in May 1975. Premature contractions might be induced by excessive taking of coffee, alcohol and tobacco during all-night vigil. ECG's recorded in February and July 1975 did not show significant changes in QRS axis, but the heart rates were decreased from 70 to 65.5 (beats/min.) and the QRS voltage (SV₁+RV₅) from 29.7 to 26.8 (mm) . There were no correlations between the decrease in heart rates or QRS voltage (SV₁+RV₅) and the changes of body weights, blood pressures, skinfold thicknesses and hematological data.
2) Pulmonary function (forced vital capacity), body weights and high jump tests were not significantly altered throughout the year. Harvard score, dynamic muscle endurance, grasping power and agility test score increased significantly in September and December. Skinfold thicknesses increased from March to September but decreased in December. Heart rates after Harvard step tests dereased in September and in December. Physical work loads were mild in the winter and heavy in the summer.
These data may be explained on the basis that immobility in the winter season during the wintering might cause deterioration of physical work capacity and induce the electro-cardiographic changes.

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The effects of bioisolation on leucocyte counts, serum immunoglobulin concentrations and normal microbial flora were studied at two Japanese Antarctic Survey bases, Syowa Station and Mizuho Camp, during 17th Japanese Antarctic Research Expedition from 1975 to 1977.
Thirteen wintering members were divided into two groups; one was composed of six men who wintered at Syowa Station (Syowa group) and the other was composed of seven men at Mizuho Camp (Mizuho group) . The following results were obtained;
1. Microbiological observation revealed the facts that the drinking water of Syowa Station was highly polluted but that of Mizuho Camp was relatively sterile.
2. In Syowa group, total aerobic microorganisms, especially bacillus spp., in feces were increased significantly in number during early period of wintering, while in Mizuho group, those were decreased significantly after wintering. Pharyngeal microbial flora did not change significantly.
3. In Syowa group, leucocyte counts and serum immunoglobulin concentrations of Ig G and Ig A were increased significantly during early period of wintering. In Mizuho group, leucocyte counts did not change significantly, but Ig G waa decreased significantly after wintering.
Above results suggest that 1) the changes of microbiological environment alter the composition of normal human microbial flora, 2) those altered microbial flora, especially aerobic microorganisms, can change the host's immunological status, and 3) the changes of leucocyte counts and immunoglobulin concentrations may be resulted from altered intestinal microbial flora.

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Circadian rhythms of locomotor activity and plasma corticosterone were determined simultaneously in individual rats which were injected intracerebroventricularly with 6-hydroxy-dopamine (6-OHDA), a specific depletor of catecholamines. Under light-dark cycles (LD), 6-OHDA treated rats showed essentially normal circadian rhythms of both functions. Under 200 1ux continunous light (LL) the locomotor activity in the drug-treated rats ran freely with a period slightly longer than 24.0 hr, free-running parameters such as level, amplitude and period of the locomotor activity being the same with those of control rats. The circadian rhythm of plasma corticosterone in control rats also ran freely under LL, resulting in a reversal of their phase after 12 days exposure to LL. However, the rhythm disappeared in 6-OHDA treated rats under LL. These results suggest that the brain catecholaminergic components are indispensable for the circadian rhythm of plasma corticosterone to freerun normally under LL, but are dispensable under LD. A pausible model consisting of two oscillators is proposed to explain these findings.

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Previously I reported that Congo red clearance from the blood of rats was faster in the dark period than in the light, and further, it was faster in the younger animals than the older. In the present study using Salmonella enteritidis instead of Congo red, the relationship was completely reversed; the clearance from the blood was faster in the light period and in the older age group than in the dark and in the younger group.
The difference of the clearance rate between Congo red and S. enteritidis is supposed to be due to the different physicochemical nature of surface of particles of chemical substance and living organism.

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The effect of constant illumination (LL) on circadian sleep rhythm and sexual cycle were studied in female albino rats (Sprague-Dawley, SD), hooded rats (Long-Evans, LE) and SD rats born and reared in LL. Cortical EEGs and dorsal neck EMG were used to monitor slow wave sleep (SWS), paradoxical sleep (PS) and alertness. The sums of the duration of each SWS and PS were expressed for each two hours. The bihourly distributions of SWS and PS in each animal were illustrated as graphs of circadian sleep rhythm. All experiments were performed under constant temperature (24±0.5°C) and humidity (45-55%) .
1. The strain differences between LE and SD were observed in circadian sleep rhythm under control lighting schedule (LD) . The circadian sleep rhythm in SD rats showed the sexual differentiation and the changes during sexual cycle. While in LE rats, any differences of sleep rhythm were not observed between both sexes or during sexual cycle.
2. The long term LL exposure (40-50 days) of SD rats caused the persistent estrus (PE), disrupted the circadian sleep rhythm and resulted the ultradian sleep rhythm of 4-6 hours periods. After the long term LL exposure of more than 6 months, SD rats returned to LD schedule. One month after returning to LD schedule, 3 out of 8 rats recovered the regular sexual cycle and showed the regular circadian sleep rhythm similar to control. While, the other rats showed PE or irregular sexual cycle and indicated the regular SWS rhythm, but the phase of PS rhythm in these rats was dissociated from that of SWS rhythm. On the other hand, LL exposure of LE rats also caused PE, but delayed more 30 days than SD rats. Furthermore, the electrodes implantation for these PE-LE rats recovered the sexual cycle and maintained over 50 days. The sleep rhythm in LL exposed LE rats indicated ultradian rhythm, but still maintained the circadian freerunning rhythm.
3. In the SD rats born and reared in LL, the completion of PE delayed more 20 days than control rats. The sleep rhythm in these rats showed the circadian freerunning rhythm and the changes during sexual cycle.
From these results, it is suggested that LE rats are less effective to LL exposure than SD rats and SD rats born and reared in LL may have the inheritable circadian freerunning hrythm. But, it is the future problem to elucidate the mechanism of these phenomena.

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Seasonal distribution of births of 9, 868 schizophrenic patients and 1, 795 manic-depressive patients in Tokyo born during the period 1841-1960 and treated at two hospitals during the period 1879-1976 was investigated by year of birth and sex.
Both schizophrenic and manic-depressive birth distributions showed deviations from the control. How the distributions deviated was different by year of birth and sex of the patients. The deviations per se, could be seen in both male and female patients.
Considering the fact that birth seasonality of psychotic patients varied by period of birth and sometimes by sex, it is suspected that those“endogenous”mental diseases may be prepared by plural exogenous seasonal epidemic factors which act on fetal or neonatal stages and some of which may interact with sex difference.

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