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Volume 18 (1981)
- Issue 3 Pages 9-
- Issue 2 Pages 65-
- Issue 1 Pages 1-
Volume 18, Issue 1
Displaying 1-6 of 6 articles from this issue
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Hiroyuki SHIBATA, Kozo HIRATA, Tetsuo NAGASAKA1981 Volume 18 Issue 1 Pages 1-8
Published: April 15, 1981
Released on J-STAGE: October 13, 2010
JOURNAL FREE ACCESSFour groups of unanesthetized conscious Wistar rats were confined individually in a direct calorimeter of which wall temperature (TW) was kept at 14±0.1°C. Heat production (M), heat loss (HL=R+C+E; sum of radiative, convective, conductive, and evaporative heat loss), colonic temperature (Tcol) and heart rate (HR) changes after subcutaneous injections of one of the following drugs were studied; norepinephrine (NE, 0.4mg⋅kg-1), phenylephrine (PHE, 0.4 mg⋅kg-1), isoproterenol (INE, 0.05mg⋅kg-1) and norepinephrine (0.4mg⋅kg-1) after premedication with atropine (3 mg⋅kg-1) . lnjections of the drugs were performed through an indwelling catheter from the outside of the calorimeter without causing any emotional stress on the rats.
At this Tw, NE, PHE and 1NE produced a significant fall in Tcol (p<0.05) . With NE and PHE, M decreased greatly with a concomitant fall in HR. HLslightly increased for the initial 30 minutes and declined thereafter. For this initial period following NE and PHE injections, heat storage became negative due to a marked reduction of M. NE did not produce such decreases in HR, M and Tcol in the atropinized rats. In contrast, INE produced an increase in M with a concomitant slight increase in HR. HL, particularly (R+C), increased more than M. Heat storage became, again, negative and Tcol fell gradually in these rats. The increased (R+C) suggests an increased blood flow in the skin following administrations of 1NE at this Tw.
With NE and PHE, the fall in HR was nearly 30% and the reduction of cardiac output (Q) was suggested. The decrease in heat production after NE and PHE injections may be attributed to the reduction of Q and its fractional distribution to the calorigenic tissues such as brown adipose tissues.View full abstractDownload PDF (938K) -
Masanori NAGAI, Masami IRIKI, Klaus PLESCHKA1981 Volume 18 Issue 1 Pages 9-23
Published: April 15, 1981
Released on J-STAGE: October 13, 2010
JOURNAL FREE ACCESSCharacteristics of vasodilation in the nose and tongue were investigated, employing electrical stimulation of the brainstem in anesthetized, immobilized dogs.
Dilator points for the nose and/ or tongue were found through the ventral part of the brainstem from the hypothalamus to upper pontine region.
Vasodilation of the nose was not altered by atropine, but abolished by vagosympathectomy, administration of phenoxybenzamine, or reserpine pretreatment. This indicates that vasodilation of the nose is caused by a decrease in vasoconstrictor tone of postganglionic fibres passing cervical sympathetic trunk. Vasodilation of the tongue was not abolished by atropine, vagosympathectomy and phenoxybenzamine, oxprenolol and reserpine treatments, but abolished by ganglion blockade with hexamethonium. Vasodilation of the tongue is suggested to be induced by a non-cholinergic, non-adrenergic mechanism containing fibres running partially apart from the cervical sympathetic trunk. This mechanism would functionally participate in the lingual vasodilation accompanied by thermal panting.View full abstractDownload PDF (1684K) -
Tomoko TSURUTANI-MIDORIKAWA1981 Volume 18 Issue 1 Pages 24-30
Published: April 15, 1981
Released on J-STAGE: October 13, 2010
JOURNAL FREE ACCESSTo observe possible influences of the biological clock on thermoregulatory responses, heat balance was measured on 12 healthy students wearing only shorts during 1 h heat (40°C, 60 r, h.) and cold (10°C, 60% r, h.) exposure in the rising phase (9: 00-42: 00) and in the falling phase (21: 00-24: 00) of body temperature. In the cold environment, the higher metabolic rate was observed more often in the rising phase than in the falling phase in winter, but not in summer. In the hot environment, the rate of evaporative heat loss was more increased in the falling phase than in the rising phase for both seasons. In the cold environment, shivering was more intensive and lasted longer in the rising phase than in the falling phase in winter. In the hot environment, evaporative sweat rate was significantly higher in the falling phase than in the rising phase. The tendency was marked more in summer than in winter. The mean body temperature, however, changed to a similar extent in the rising phase and in the falling phase for both seasons when the circadian temperature variations are balanced. The analysis of these results implies that the increased sweating in the falling phase is brought about by the changes in the threshold and not by the changes in the sensitivity of thermoregulatory responses.View full abstractDownload PDF (994K) -
Taketoshi MORIMOTO, Kenju MIKI, Hiroshi NOSE, Seiji YAMADA, Kazufumi H ...1981 Volume 18 Issue 1 Pages 31-39
Published: April 15, 1981
Released on J-STAGE: October 13, 2010
JOURNAL FREE ACCESSEight male subjects were exposed to heat (36°C, 70% RH) and exercise stress for 2 hours, and plasma volume, hematocrit value, concentration of plasma protein, blood water content, plasma osmolality and concentrations of ions in plasma were determined together with sweat and urine volume and their ionic compositions. These observations were repeated on each subjects three times: without any fluid replacement (dehydration exp.), with free access to tap water (water exp.) and with free access to a glucose-electrolyte solution (G-E exp.) . The results obtained are as follows: 1) The degree of voluntary dehydration was significantly higher in water exp. than in G-E exp. 2) In dehydration exp., significantly higher loss of water in erythrocyte and increase in plasma chloride concentration were observed, which suggest the shift of water from intracellular compartment. 3) Changes in plasma protein concentration, osmolality and water contents in blood showed significantly quick recovery in G-E exp. It is still to be determined whether these differences are due to the difference in the amount of ingestion or due to the quick absorption of glucose-electrolyte solution.View full abstractDownload PDF (1156K) -
Makoto MAYUZUMI, Nobuo TANAKA, Junzo TSUJITA, Seiki HORI1981 Volume 18 Issue 1 Pages 40-45
Published: April 15, 1981
Released on J-STAGE: October 13, 2010
JOURNAL FREE ACCESSTen obese and ten lean female university students were exposed to a hot environment in summer. Experiments were carried out at around 15: 00 h. The subjects were instructed to fast and rest at least two hours before the experiment. The women whose body fat content was more than 19% were defined as obese subjects and those whose boby fat content was less than 15% were defined as lean subjects. After having been in a room of 30°C with 70% R. H. for 60min, subjects, during follicular phase of menstrual cycle, clad in swimming suits, immersed theis legs up to the knees into a water bath of 42°C for 60min. The obese subjects showed lower skin temperature, higher oral temperature, lower metabolic rate per body weight and lower conductive convective heat transfer coefficient from core to shell than the lean subjects before immersion of legs in the hot water. The obese subjects showed less rise in oral temperature, lower local sweat rate, less body weight loss per body weight and less metabolic rate per body weight in a hot bath. A higher oral temperature in spite of lower metabolic rate per body weight for obese subjects at 30°C before immersion of their legs into a hot bath could reflect their lower skin temperature caused by thicker subcutaneous fat layer. The evidence of less rise in oral temperature and less weight loss per body weight in obese subjects in a hot bath may be explained by less heat load per body weight due to smaller skin surface of legs per body weight and thicker subcutaneous fat layer of calves.View full abstractDownload PDF (793K) -
Takeshi SHINOHARA, Yoshio NAGAO, Norimasa OKABE, Kinichi HAMAGUCHI, Ta ...1981 Volume 18 Issue 1 Pages 46-58
Published: April 15, 1981
Released on J-STAGE: October 13, 2010
JOURNAL FREE ACCESSMeasurements of physiological parameters of adaptation to altitude and recording of subjective, self-rating check list for the severity of symptoms of acute mountain sickness were carried out in 7 Japanese members and 8 Sherpas of the Expedition to Ganesh Himal V (6950m), 1980. Results obtained are as follows:
1. Resting pulse rate measured at the basal condition of immediately after awakening in the morning (basal pulse rate, BPR) was increased with attaining altitude above 3000m markedly in Japanese members and moderately in Sherpas. Initial elevated BPR after attaining new higher altitude showed recovering trend with the lapse of sojourn day there. But this trend was not found at the altitude above 5800m.
2. Breath-holding time of Japanese members was shortened with attaining higher altitude.
3. Resting respiratory minute volume, VEBTPS, increased markedly with attaining altitude, while VESTPDwas maintained almost constant level regardless of altitude in both Japanese and Sherpa groups.
4. Hemoglobin concentration increased gradually during the sojourn for approximately one month at altitude above base camp (3800m) in both groups. However, the initial values of Sherpas measured at Kathmandu (1250m) were signif ivantly higher than that of Japanese members.
5. Objective and subjective symptoms of acute mountain sickness which is recorded in the self-rating check list appeared more frequently in Japanese members than in Sherpas. Besides, these symptoms began to appear at lower altitude, were more serious in severity and continued over a longer period of time in Japanese members than in Sherpas.
6. Mountain sickness score, which is calculated from the record of self-rating check list including the changes in BPR, was suggested to be useful in self-evaluation of the capability of continuing the climbing activity.View full abstractDownload PDF (1858K)
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