Effects of apomorphine on thermoregulatory responses of rats to different ambient temperatures

1979 ◽  
Vol 57 (5) ◽  
pp. 469-475 ◽  
Author(s):  
M. T. Lin ◽  
Y. F. Chern ◽  
Zyx Wang ◽  
H. S. Wang
Keyword(s):  
Skin Temperature ◽  
Dopamine Neurons ◽  
Induced Hypothermia ◽  
Evaporative Heat Loss ◽  
Central Administration ◽  
Mean Skin Temperature ◽  
Ambient Temperatures ◽  
6 Hydroxydopamine ◽  
Sites Of Action ◽  
Skin Temperatures

Either systemic or central administration of apomorphine produced dose-related decreases in rectal temperature at ambient temperatures (Ta) of 8 and 22 °C in rats. At Ta = 8 °C, the hypothermia was brought about by a decrease in metabolic rate (M). At Ta = 22 °C, the hypothermia was due to an increase in mean skin temperature, an increase in respiratory evaporative heat loss (Eres) and a decrease in M. This increased mean skin temperature was due to increased tail and foot skin temperatures. However, at Ta = 29 °C, apomorphine produced increased rectal temperatures due to increased M and decreased Eres. Moreover, the apomorphine-induced hypothermia or hyperthermia was antagonized by either haloperidol or 6-hydroxydopamine, but not by 5,6-dihydroxytryptamine. The data indicate that apomorphine acts on dopamine neurons within brain, with both pre- and post-synaptic sites of action, to influence body temperature.

Effects of brain monoamine depletion on chlorpromazine-induced hypothermia in rabbits

1979 ◽  
Vol 57 (1) ◽  
pp. 16-23 ◽  
Author(s):  
M. T. Lin
Keyword(s):  
Blood Flow ◽  
Heat Production ◽  
Intraperitoneal Administration ◽  
Induced Hypothermia ◽  
Evaporative Heat Loss ◽  
Ambient Temperatures ◽  
Normal Limits ◽  
Wide Range ◽  
Monoamine Depletion ◽  
6 Hydroxydopamine

The thermal responses of three groups of control, 6-hydroxydopamine (6-OHDA) treated and 5,7-dihydroxytryptamine (5,7-DHT) treated rabbits to the administration of chlorpromazine (CPZ) were assessed at three different ambient temperatures (Ta: 2, 22, and 32 °C). Depleting catecholamines (CA) in brain with 6-OHDA produced a decrease in metabolic rate, in respiratory evaporative heat loss, and in ear blood flow at both Ta's of 2 and 22 °C, while depleting 5-hydroxytryptamine (5-HT) contents in brain with 5,7-DHT produced the opposite responses at the same Ta's. However, these amine-depleted animals maintained their rectal temperatures within normal limits over a wide range of Ta's tested. Furthermore, intraperitoneal administration of CPZ produced hypothermia at both Ta's of 2 and 22 °C. The major cause of the CPZ-induced hypothermia was an inhibition of metabolic heat production at Ta of 2 °C. At Ta of 22 °C, the CPZ-induced hypothermia was due to both a decrease in heat production and an increase in ear blood flow. However, CPZ hypothermia was attenuated in the CA-depleted animals, but was potentiated in the 5-HT-depleted animals. The data indicate that brain monoamines are involved in the central mechanisms of CPZ-induced hypothermia.

Thermoregulatory responses during competitive marathon running

1977 ◽  
Vol 42 (6) ◽  
pp. 909-914 ◽  
Author(s):  
M. B. Maron ◽  
J. A. Wagner ◽  
S. M. Horvath
Keyword(s):  
Skin Temperature ◽  
Marathon Running ◽  
Heat Illness ◽  
Mean Skin Temperature ◽  
Total Water ◽  
Water Losses ◽  
Thermoregulatory Responses ◽  
Marked Disparity ◽  
Skin Temperatures ◽  
Cool Conditions

To assess thermoregulatory responses occuring under actual marathon racing conditions, rectal (Tre) and five skin temperatures were measured in two runners approximately every 9 min of a competitive marathon run under cool conditions. Race times and total water losses were: runner 1 = 162.7 min, 3.02 kg; runner 2 = 164.6 min, 2.43 kg. Mean skin temperature was similar throughout the race in the two runners, although they exhibited a marked disparity in temperature at individual skin sites. Tre plateaued after 35--45 min (runner 1 = 40.0--40.1, runner 2 = 38.9--39.2 degrees C). While runner 2 maintained a relatively constant level for the remainder of the race, runner 1 exhibited a secondary increase in Tre. Between 113 and 119 min there was a precipitous rise in Tre from 40.9 to 41.9 degrees C. Partitional calorimetric calculations suggested that a decrease in sweating was responsible for this increment. However, runner 1's ability to maintain his high Tre and running pace for the remaining 44 min of the race and exhibit no signs of heat illness indicated thermoregulation was intact.

Extremity skin temperature in British and Zebu cross cattle

1967 ◽  
Vol 69 (1) ◽  
pp. 1-7 ◽  
Author(s):  
K. G. Johnson ◽  
M. E. D. Webster
Keyword(s):  
Skin Temperature ◽  
Lower Leg ◽  
Zebu Cattle ◽  
Temperature Changes ◽  
Ambient Temperatures ◽  
Thermal Environments ◽  
Air Temperatures ◽  
Environmental Temperatures ◽  
Skin Temperatures ◽  
Trunk Skin

1. Extremity skin temperature changes in British and Zebu cross cattle examined in moderate thermal environments followed a thermoregulatory pattern similar to that describedby Whittow (1962). At low environmental temperatures, ear and lower leg skin temperatures were usually only slightly above air temperature. At a variable time after air temperatures began to rise or the animals were fed, extremity skin temperatures increased suddenly to near trunk skin temperature.2. In eight of the ten pairs of animals studied in rising ambient temperatures and during feeding after fasting for 36–72 hr, increases in ear temperature were measured in the British animal before similar changes occurred in its Zebu counterpart. Changes in lower leg skin temperature followed a similar pattern.Trunk skin temperatures and respiratory frequencies were significant higher in British cross animals than in Zebu cross animals of similar thermal history. The mean rectal temperature of both British and Zebu cattle was 38·5 °C.

Effects of phentolamine on thermoregulatory functions of rats to different ambient temperatures

1979 ◽  
Vol 57 (12) ◽  
pp. 1401-1406 ◽  
Author(s):  
M. T. Lin ◽  
Andi Chandra ◽  
T. C. Fung
Keyword(s):  
Heat Loss ◽  
Rectal Temperature ◽  
Heat Production ◽  
Room Temperature ◽  
Metabolic Heat Production ◽  
Central Component ◽  
Evaporative Heat Loss ◽  
Central Administration ◽  
Ambient Temperatures ◽  
Metabolic Heat

The effects of both systemic and central administration of phentolamine on the thermoregulatory functions of conscious rats to various ambient temperatures were assessed. Injection of phentolamine intraperitoneally or into a lateral cerebral ventricle both produced a dose-dependent fall in rectal temperature at room temperature and below it. At a cold environmental temperature (8 °C) the hypothermia in response to phentolamine was due to a decrease in metabolic heat production, but at room temperature (22 °C) the hypothermia was due to cutaneous vasodilatation (as indicated by an increase in foot and tail skin temperatures) and decreased metabolic heat production. There were no changes in respiratory evaporative heat loss. However, in the hot environment (30 °C), phentolamine administration produced no changes in rectal temperature or other thermoregulatory responses. A central component of action is indicated by the fact that a much smaller intraventricular dose of phentolamine was required to exert the same effect as intraperitoneal injection. The data indicate that phentolamine decreases heat production and (or) increases heat loss which leads to hypothermia, probably via central nervous system actions.

Thermoregulation in Exercising White Rats

1973 ◽  
Vol 51 (11) ◽  
pp. 814-824 ◽  
Author(s):  
K. Myhre ◽  
B. Hellstrøm
Keyword(s):  
Thermal Stress ◽  
Skin Temperature ◽  
Albino Rats ◽  
Cold Environment ◽  
Exercise Time ◽  
Ambient Temperatures ◽  
Warm Environment ◽  
White Rats ◽  
Skin Temperatures ◽  
Trunk Skin

Colonic temperatures (TC), heart rates (HR), back skin and tail skin temperatures (TST) were measured in six warm acclimated (+24 °C) male albino rats running on a treadmill at three different work loads (HR ranging from 400 beats/min to 500 beats/min). Ambient temperatures (TA) ranged from about +8 °C to about +30 °C. TC increased immediately upon onset of work. Exercising in a cold environment ultimately made the rats hypothermic and in a warm environment hyperthermic. Within the limits set by the external thermal stress the rats controlled TC independently of the work intensity.High trunk skin temperatures were recorded in all experiments. Exercise in cold and cool environments produced tail skin vasoconstriction. In the 21 °C environment half of the rats produced tail skin vasodilation. In the 28 °C environment most experiments produced this effect. Cessation of work was accompanied by prompt vasoconstriction. The results indicated that exercise time before tail vasodilation was affected by exercise as well as by the tail skin temperature prior to vasodilation.

Thermal comfort in relation to mean skin temperature

1970 ◽  
Vol 48 (2) ◽  
pp. 98-101 ◽  
Author(s):  
E. D. L. Topliff ◽  
S. D. Livingstone
Keyword(s):  
Thermal Comfort ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Incident Radiation ◽  
Mean Skin Temperature ◽  
Ambient Temperatures ◽  
The Mean ◽  
Per Se

Nude men were exposed to a range of ambient temperatures and were brought to a condition of thermal comfort by adjustment of the incident radiation. The mean skin temperature associated with comfort was found to be different for each combination of ambient temperature and incident radiation. It was evident that mean skin temperature, per se, was not a dependable criterion of thermal comfort.

Bombesin-Induced Hypothermia in the Insulin-Treated Rat: Effect on Tail-Skin Temperature

1989 ◽  
Vol 69 (3-2) ◽  
pp. 1339-1345
Author(s):  
Alex M. Babcock ◽  
Chris Barton
Keyword(s):  
Central Nervous System ◽  
Skin Temperature ◽  
Heat Loss ◽  
Preoptic Area ◽  
Core Body Temperature ◽  
Induced Hypothermia ◽  
Autonomic Functions ◽  
Core Body ◽  
Skin Temperatures ◽  
Intrahypothalamic Injection

Bombesin-like peptides are widely distributed in the mammalian central nervous system and appear to participate in the regulation of a variety of autonomic functions. Bombesin has been shown to alter feeding behavior, locomotor activity, and thermoregulation. Microinfusion of bombesin into the preoptic area of the hypothalamus produces a reduction in core body temperature, but only if the rat has been cold-exposed, food-deprived, or pretreated with insulin. The mechanism for bombesin-induced hypothermia under the latter two conditions is unknown. The present study evaluated the possible contribution of peripheral heat loss mechanisms in bombesin-induced hypothermia. Rats were administered insulin (10U/kg, Regular Iletin I i.m.) or saline followed by an intrahypothalamic injection of bombesin (.05 μg/ .25 μl) or peptide vehicle. Rectal and tail-skin temperatures were measured continuously for 120 min. Changes in temperature were evaluated at 30, 60, 90, and 120 min., using analysis of variance. As previously demonstrated, bombesin produced hypothermia in rats pretreated with insulin. This reduction in core temperature was not associated with any significant alteration in tail-skin temperature. Results suggest that bombesin-induced hypothermia in rats pretreated with insulin may not be mediated by an increase in peripheral heat loss.

Effect of ambient temperature on development of prostaglandin E1 hyperthermia in the rhesus monkey

1978 ◽  
Vol 44 (5) ◽  
pp. 751-758 ◽  
Author(s):  
C. C. Barney ◽  
R. S. Elizondo
Keyword(s):  
Rhesus Monkey ◽  
Metabolic Rate ◽  
Rhesus Monkeys ◽  
Prostaglandin E1 ◽  
Co2 Production ◽  
Evaporative Heat Loss ◽  
Water Losses ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Skin Temperatures

Prostaglandin E1 (PGE1) hyperthermia (fever) was studied at ambient temperatures (Ta) of 18, 27, and 35 degrees C in four male unanesthetized rhesus monkeys (Macaca mulatta) implanted with four guide tubes and one reentrant tube within the preoptic anterior hypothalamus (PO/AH). Rectal, hypothalamic, and mean weighted skin temperatures, O2 consumption, CO2 production, and respiratory and total evaporative water losses were measured continuously before and during PGE1 fever at each Ta. The febrile reponse to PO/AH PGE1 injection was dose responsive and was less at a Ta of 35 degrees C than at the other Ta's. At a Ta of 18 degrees C, fever was brought about primarily by an increase in metabolic rate. At a Ta of 27 degrees C, fever was produced by an increase in metabolic rate and by skin vasoconstriction. At a Ta of 35 degrees C, fever was the result of an increase in metabolic rate and a decrease in sweating evaporative heat loss. At each Ta some generalized skin vasconstriction also occurred. During the plateau phase of the fever, the measured heat losses and gains returned to near control levels. The data indicate that the rhesus monkey shows specific thermoregulatory responses to PO/AH PGE1 injection and would be a good model for the study of thermoregulation during fever in higher primates.

Forearm blood flow during body temperature transients produced by leg exercise

1975 ◽  
Vol 38 (1) ◽  
pp. 58-63 ◽  
Author(s):  
C. B. Wenger ◽  
M. F. Roberts ◽  
J. A. Stolwijk ◽  
E. R. Nadel
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Forearm Blood Flow ◽  
Bicycle Ergometer ◽  
Vapor Pressures ◽  
Internal Temperature ◽  
Ambient Temperatures ◽  
Forearm Skin ◽  
Leg Exercise ◽  
Skin Temperatures

Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 degrees C and vapor pressures of less than 18 Torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 degrees C. Esophageal temperature (Tes) was measured with a thermocouple at the level of the left atrium, and mean skin temperature (Tsk) was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow (BF) was measured by electrocapacitance plethysmography. Our data are well accounted for by an equation of the form BF = a1Tes + q2Tsk + b, independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise. The ratios a1/a2 (7.5, 9.6, 11.7) are quite similar to the ratios (8.6, 10.4) of the corresponding coefficients in two recent models of thermoregulatory sweating.

Shorn and unshorn Awassi sheep IV. Skin temperature and changes in temperature and humidity in the fleece and its surface

1963 ◽  
Vol 60 (2) ◽  
pp. 183-193 ◽  
Author(s):  
E. Eyal
Keyword(s):  
Ambient Temperature ◽  
Skin Temperature ◽  
Vapour Pressure ◽  
The Sun ◽  
Direct Sunlight ◽  
Ambient Temperatures ◽  
Awassi Sheep ◽  
Break Points ◽  
Environmental Temperatures ◽  
Skin Temperatures

1. A comparison was made between the skin temperature, humidity and temperature within and on the surface of the fleece of unshorn and shorn sheep. This study was conducted during various seasons of the year, at different environmental temperatures, while sheep were maintained in the shade or subjected to direct sunlight.2. Accompanying the rise of ambient temperature (in the shade) from 10 to 43° C. there was an increase in skin temperature from 34 to 40° C. and from 28 to 40° C. of the unshorn and shorn sheep, respectively.3. The relationship between the rise in skin temperature and that of ambient temperature was not linear, but showed a stepwise pattern in which the ‘breaks’ occurred at similar environmental temperatures for both groups, although skin temperatures of shorn sheep were lower than the unshorn.4. The diurnal change in skin temperature of the shorn sheep was similar to that of the ambient temperature. The decrease in skin temperature of unshorn sheep sometimes lagged behind the fall in environmental temperature. The seasonal variations between summer and winter were more significant in shorn than in unshorn sheep.5. Fleece surface temperatures measured at the same ambient temperatures ranged between 13 and42° C. and 16·5–39·5° C. in the unshorn and shorn sheep, respectively. In the break points of the rise in skin temperature, there occurred a drop in temperature gradients between the skin and fleece surface. This probably indicates a rise in thermal conductivity of the fleece at these points.6. The temperature gradient per unit of fleece thickness is inversely related to the depth of fleece and is greater the nearer to the skin.7. With exposure to the sun, skin temperatures of both groups greatly increased and occasionally reached 47° C. Under these conditions the differences between shorn and unshorn groups were not consistent.8. Fleece temperatures of unshorn sheep increased greatly upon exposure to the sun. The maximal temperatures were recorded midway between the fleece surface and skin. These temperatures generally reached 55° C. and sometimes even exceeded 60° C.9. At ambient temperatures of 30–35° C. the vapour pressure close to the skin of unshorn sheep ranged between 35–40 mm. Hg. With shorn sheep, however, the vapour pressure close to the skin was similar to that of the environment. In Yotvata there was a rise in vapour pressure close to the skin when the ambient temperature increased to 40–43° C. This rise in humidity was paralleled by a rise of vapour pressure throughout the wool. It was not linear but rather showed a ‘step-wise’ pattern.10. The vapour pressure in fleece and near the skin of sheep subjected to direct sunlight increased considerably (up to 80 mm. Hg). This rise showed a wave-like curve with various degrees of persistency. Appearance of fluid on the skin of Awassi sheep was observed on several occasions.

Sign in / Sign up

Export Citation Format

Share Document