Operant control of ambient temperature during sleep deprivation. Shaw, Paul J., Bernard M. Bergmann, and Allan Rechtschaffen. Sleep Research Laboratory, Departments of Psychiatry and Psychology, University of Chicago, Chicago, Illinois, U.S.A.
APStracts 3:0318R, 1996.
Rats subjected to total sleep deprivation (TSD) by the disk over water method were provided with a continuously available operant by which they could increase ambient temperature (Tamb). TSD rats progressively increased operant responses for heat to 700% of baseline levels. During the last quarter of sleep deprivation they maintained mean Tamb at 9 degrees C above baseline and held Tamb over 40 degrees C for 35% of the day. In contrast, yoked control rats (TSC) did not change mean Tamb. Although both TSD and TSC rats showed a progressive decline in intraperitoneal temperature (Tip), TSD rats maintained an elevated Tamb even during periods when Tip and brain temperatures (Tbr) were above baseline levels. Thus, these results confirm and extend earlier findings that rats subjected to TSD show an increase in temperature setpoint (Tset). The earlier studies, which utilized short daily trials in a thermal gradient, demonstrated an increase in Tset early in the deprivation period. The present study, which obtained more extensive data on thermal preference at a range of body temperatures demonstrated an increasing Tamb for almost all Tip and Tbr values suggesting a progressive increase in Tset over the course of sleep deprivation. Surprisingly, survival time was shorter than in previous TSD studies. Reduced survival could not be attributed to differences in Tbr, Tip, EE, or sleep loss from previous studies. 

Received 31 October 1995; accepted in final form 12 August 1996.
APS Manuscript Number R676-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996