AJP - Regulatory, Integrative and Comparative Physiology, Vol 236, Issue 3 153-R161, Copyright © 1979 by American Physiological Society
Circadian control of thermoregulation in the squirrel monkey, Saimiri sciureus
C. A. Fuller, F. M. Sulzman and M. C. Moore-Ede
The characteristics and control of the circadian rhythms of core body
temperature (colonic) and skin temperature (tail) were studied in
chair-acclimatized squirrel monkeys (Saimiri sciureus). When animals were
entrained to a light-dark cycle (12 h 600 lx; 12 h less than 1 lx) these
two temperatures displayed prominent, reproducible, tightly coupled
circadian rhythms. In contsant light of 600 lx, where no other effective
circadian time cues were present, both temperature rhythms persisted with
free-running periods. Within each animal, however, these rhythms were not
as tightly coupled to one another as in LD. On occasion colonic and tail
temperature rhythms free-ran with different circadian periods and some
animals demonstrated "splitting" of the colonic temperature rhythm, with
the colonic temperature rhythm displaying a bimodal pattern. These results
suggest that the circadian rhythm of body temperature in primates is under
the control of more than one potentially independent circadian oscillator.
