Warm sensitive
neurons (WSN)
play a major
role not only in
body temperature regulation, but also in
sleep regulation. The present study was undertaken to investigate the
role of WSN of the
preoptic area (
POA) in
mediating the ambient
temperature (Tamb) related changes in
sleep. The effect of Tamb changes on
sleep and
body temperature was studied in
rats before and after destruction of WSN of the
POA by local intracerebral
injection of
capsaicin. Though the
rats preferred 27°C Tamb, they slept maximum at 30°C. After destruction of WSN of the
POA,
slow wave sleep (SWS) peak was brought down to 27°C, which was the preferred Tamb of the
rats. This indicates that WSN of the
POA mediate the increase in SWS, at
temperatures higher than preferred Tamb. On the other
hand, in WSN destroyed
rats,
rapid eye movement (REM)
sleep was maximum at 33°C. It suggests that the
REM sleep generation is under inhibitory control of the WSN of the
POA. The study supports several earlier
reports that the
neurons of the
POA play a key
role in coordinating
sleep and
body temperature regulation.