AJP - Regulatory, Integrative and Comparative Physiology, Vol 241, Issue 5 301-R306, Copyright © 1981 by American Physiological Society
Thermal balance in ketamine-anesthetized rhesus monkey Macaca mulatta
W. S. Hunter, K. R. Holmes and R. S. Elizondo
A partitional calorimetry study compared thermoregulatory responses of
unanesthetized adult rhesus monkeys (4 female, 1 male) to those
anesthetized with ketamine HCl and exposed to ambient temperature (Ta) of
18, 29, 38 degrees C. Steady-state metabolic heat production (M), mean skin
temperature (Tsk), rectal temperature (Tre), respiratory evaporative heat
loss (Eres), and total evaporative heat loss (Etot) were measured at each
Ta. Average Tre of anesthetized animals was reduced by approximately 1
degree C at Ta 18 degrees C, but thermal balance in anesthetized and
control animals was maintained by reflexly decreased tissue conductance and
shivering. For anesthetized animals, the average M increased 1.8 times over
the lowest value of 40.13 W/m2 at Ta 29 degrees C, compared to a 1.5-fold
increase for controls. Responses for both groups were not different at Ta
29 degrees C, both groups regulated body temperatures by vasodilation and
increased sweating, but with ketamine sweating was reduced (35%). Effective
tissue thermal conductance (K) was lowest at Ta 18 (10.8 W/m2 . degrees C)
and increased to 39.4 W/m2 . degrees C at Ta 38 degrees C. No significant
difference in K was found between ketamine and control groups at other
Ta's.
