AJP - Regulatory, Integrative and Comparative Physiology, Vol 248, Issue 5 567-R572, Copyright © 1985 by American Physiological Society
Forced internal desynchronization between circadian temperature and activity rhythms in squirrel monkeys
P. H. Gander, R. Lydic, H. E. Albers and M. C. Moore-Ede
In an attempt to force internal desynchronization between the rest-activity
rhythm and the body temperature rhythm of the squirrel monkey (Saimiri
sciureus), five animals were studied in a 14:14 light-dark cycle. In four
animals a 28-h spectral component was found to predominate in the
rest-activity rhythm, whereas an unentrained circadian component (tau =
25.9 +/- 0.4 h) predominated in the body temperature rhythm. Plots of the
cycle-by-cycle acrophases of the two rhythms confirm that they
desynchronize, due to the failure of the temperature rhythm to entrain to
the light-dark cycle. These data from intact animals provide further
support for the hypothesis that the squirrel monkey circadian timing system
has at least two pacemakers. A rhythm for which the supra-chiasmatic nuclei
(SCN) have previously been shown to be essential (rest-activity)
simultaneously exhibited a different period from a rhythm (body
temperature) that has been shown to persist after destruction of the SCN.
