AJP - Regulatory, Integrative and Comparative Physiology, Vol 271, Issue 6 1753-R1758, Copyright © 1996 by American Physiological Society
Body temperature and sleep in intact and ovariectomized female rats
H. Li and E. Satinoff
Department of Psychology, University of Illinois at Urbana-Champaign 61820, USA.
The present study examined intact and ovariectomized adult rats to assess
the effects of removal of sex hormones on body temperature (Tb) and sleep.
Subjects were 12 female rats, aged 5-8 mo, half of which were bilaterally
ovariectomized (OVX). Sleep or waking and Tb were recorded under a 12:12-h
light-dark cycle. There was a strong coupling between level of Tb and the
three conditions of waking, slow-wave sleep (SWS), and rapid eye movement
sleep (REMS): Tb was significantly positively correlated with waking and
significantly negatively correlated with SWS and REMS. These correlations
were even higher in OVX rats. In the light, OVX rats had more SWS and
stayed awake less than did the intact rats. OVX rats had more REMS than did
intact rats in both light and dark. Mean Tb and daily Tb amplitude were the
same in both groups. These results suggest that ovariectomy increases and,
by extension, gonadal steroids decrease, the coupling between Tb and sleep.
