Behavioral thermoregulation in mice subjected to high pressure

1989 ◽  
Vol 66 (1) ◽  
pp. 238-244 ◽  
Author(s):  
A. G. Macdonald ◽  
N. R. Marshall ◽  
R. G. Pertwee

Mice exposed to normoxic He and Ne at increased pressure and allowed to choose between a neutral and a cool environment showed a preference for the cooler environment. This behavior was apparent at 5.7 but not at 2.5 atm He. At 11.3 atm He and Ne, the behavior was associated with a similar reduction in the deep body temperature to a new steady level. The reduction in body temperature increased with pressure, up to 35 atm He, the maximum studied. Since the heat transfer of the He and Ne gas mixtures is different and both gases exert negligible anesthetic effects, the hydrostatic pressure most likely affects behavioral thermoregulation by affecting neuronal function.

1986 ◽  
Vol 61 (5) ◽  
pp. 1623-1633 ◽  
Author(s):  
R. G. Pertwee ◽  
N. R. Marshall ◽  
A. G. Macdonald

Mice exposed to subanesthetic partial pressures of N2O (0.25 to 0.75 atm) or N2 (5.7 or 11.33 atm) and allowed to choose between a warm and a cool environment showed a marked preference for the cooler environment. This behavior was associated with the onset of hypothermia, with deep body temperature falling by up to about 3 degrees C, usually to a new, steady level. Both the length of time spent in the cooler environment and the degree of the hypothermia produced increased with the partial pressure of N2O or N2 used. The effects of N2O on behavioral thermoregulation and body temperature were reversible. There was a correlation between anesthetic potency and the ability of both gases to alter thermoregulation, suggesting that the effect of these agents on thermoregulation was caused by the same molecular interactions as those which underlie anesthesia. Since both gases elicited changes in behavioral thermoregulation promoting rather than opposing the onset of hypothermia, it is concluded that they may have acted to lower the level at which deep body temperature was being regulated.


2004 ◽  
Vol 64 (3b) ◽  
pp. 719-724 ◽  
Author(s):  
R. G. Silva

Heat transfer from skin surface to ambient water is probably the most important aspect of thermal balance in marine mammals, but the respective calculations depend on knowing the surface temperature (T S), the direct measurement of which in free animals is very difficult. An indirect iterative method is proposed for T S prediction in free cetaceans from deep body temperature, swimming speed, and temperature and thermodynamic properties of the water.


2002 ◽  
Vol 16 (4) ◽  
pp. 354-357 ◽  
Author(s):  
Michiaki Yamakage ◽  
Sohshi Iwasaki ◽  
Akiyoshi Namiki

1992 ◽  
Vol 26 (3) ◽  
pp. 191-198 ◽  
Author(s):  
Kazushi Daimon ◽  
Naoto Yamada ◽  
Tetsushi Tsujimoto ◽  
Saburo Takahashi

1987 ◽  
Vol 39 (3) ◽  
pp. 367-370 ◽  
Author(s):  
Mark S. Blumberg ◽  
Julie A. Mennella ◽  
Howard Moltz

1992 ◽  
Vol 163 (1) ◽  
pp. 139-151 ◽  
Author(s):  
R. M. BEVAN ◽  
P. J. BUTLER

Six tufted ducks were trained to dive for food at summer temperatures (air, 26°C, water, 23°C) and at winter temperatures (air, 5.8°C, water 7.4°C). The mean resting oxygen consumption (Voo2) a t winter temperatures (rwin) was 90% higher than that at summer temperatures (Tsum), but deep body temperatures (Tb) were not significantly different. Diving behaviour and mean oxygen consumption for dives of mean duration were similar at Twin and at Tsum, although the mean oxygen consumption for surface intervals of mean duration was 50% greater at Twin and Tb was significantly lower (1°C) at the end of a series of dives in winter than it was in summer. There appears to be an energy saving of 67 J per dive during winter conditions and this may, at least partially, be the result of the metabolic heat produced by the active muscles being used to maintain body temperature. While at rest under winter conditions, this would be achieved by shivering thermogenesis. Thus, the energetic costs of foraging in tufted ducks in winter are not as great as might be expected from the almost doubling of metabolic rate in resting birds.


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