Forced internal desynchronization between circadian temperature and activity rhythms in squirrel monkeys.
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.
D000818:Animals; D001831:Body Temperature; D002427:Cebidae / Q000502:physiology*; D002940:Circadian Rhythm; D004326:Drinking; D004435:Eating; D006854:Hydrocortisone / Q000134:cerebrospinal fluid; D008550:Melatonin / Q000134:cerebrospinal fluid; D009043:Motor Activity; D012453:Saimiri / Q000502:physiology*
D008550:Melatonin; D006854:Hydrocortisone