Aging alters the serotonergic modulation of light-induced phase
advances in golden hamsters.
Penev, P. D., F. W. Turek, E. P. Wallen, P. C. Zee.
Center for Circadian Biology and Medicine, Department of
Neurobiology and Physiology, Northwestern University, Evanston, IL
60208
APStracts 3:0309R, 1996.
Recent findings have raised the possibility that some of the age
-related changes in the circadian system and the response of the
circadian pacemaker to environmental stimuli may involve central
serotonergic mechanisms. The present study compared the effects of
pretreatment with the serotonin agonist, 8-OH-DPAT (5 mg/kg i.p.), on
the magnitude of light-induced phase advances in young (2-4 mo) and
old (18-20 mo) golden hamsters. The ability of this 5-HT agonist to
attenuate the photic phase resetting of circadian locomotor
rhythmicity in young animals was decreased by 46 % in old hamsters (p
< 0.05). These results suggest that deficits in the mechanisms
for serotonergic control of circadian function may interfere with the
optimal adaptation of the senescent organism to its temporal
environment.
Received 29 January 1996; accepted in final form 30 July 1996.
APS Manuscript Number R60-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996