Pregnancy-associated sleep changes in the rat.
Kimura, Mayumi, Shi-Qing Zhang, and Shojiro Inou[acute]e.
Division of Biocybernetics, Institute for Medical and Dental
Engineering, Tokyo Medical and Dental University, Tokyo 101,
Japan
APStracts 3:0138R, 1996.
Sleep disorder during the course of pregnancy has been recently
recognized in humans. However, the underlying mechanism of pregnancy
-associated sleep disorder remains undetermined, and sleep changes
even during normal pregnancy have not been fully understood. To
describe the effects of pregnancy on sleep, sleep-wake patterns
before and after fertile mating were compared in an animal model.
Baseline recordings of sleep and brain temperature were made
throughout a normal 4-d estrous cycle in female rats. After the rats
became pregnant, the recordings continued across the entire pregnant
period. As compared to baseline sleep before mating, both non-rapid
-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS)
increased significantly from the first night of pregnancy. Although
REMS returned to the baseline level from mid pregnancy, nocturnal
NREMS stayed enhanced during the entire pregnant period. Daytime
sleep fluctuated towards the end of pregnancy. Brain temperature was
elevated during the early period of pregnancy, but did not correlate
with enhanced sleep. The results suggest that physiological changes
in different stages of pregnancy may contribute to the regulation of
maternal sleep and temperature.
Received 6 November 1995; accepted in final form 2 April 1996.
APS Manuscript Number R688-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 16 April 96