AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 5 607-R610, Copyright © 1983 by American Physiological Society

ARTICLES

Temperature dependence of the hamster circadian pacemaker

F. P. Gibbs

Blind male hamsters were maintained in running-wheel cages in a LD 12:12 light-dark cycle. After regular running patterns were established hypothermia was induced by ether anesthesia, wetting of the fur with ethanol, and cooling with ice. The hamsters were kept hypothermic for 3-24 h at colonic temperatures from 10 to 20 degrees C. Following hypothermia the animals were rewarmed and replaced in their home cages. Examination of the locomotor activity records showed phase shifts (delays) in activity onset that were correlated with the temperature and duration of the hypothermia but not with the circadian time at which the hypothermia was administered. The data were interpreted to mean that the circadian pacemaker was running at a reduced rate during the hypothermic bout. Calculation of the Q10 for the rate of the clock during hypothermia produced a range from 1.08 to 1.34 depending on the method of calculation. When compared with earlier data gathered from rats under similar conditions, the hamsters circadian pacemaker appears to be better temperature compensated.

This article has been cited by other articles:

				T. M. Jarsky and R. Stephenson Effects of hypoxia and hypercapnia on circadian rhythms in the golden hamster (Mesocricetus auratus) J Appl Physiol, December 1, 2000; 89(6): 2130 - 2138. [Abstract] [Full Text] [PDF]

				N. F. Ruby, D. E. Burns, and H. C. Heller Circadian Rhythms in the Suprachiasmatic Nucleus are Temperature-Compensated and Phase-Shifted by Heat Pulses In Vitro J. Neurosci., October 1, 1999; 19(19): 8630 - 8636. [Abstract] [Full Text] [PDF]