Stimulation of cholinergic receptors in the medial preoptic area
affects sleep and cortical temperature.
Imeri, Luca, Susanna Bianchi, Piero Angeli, and Mauro Mancia.
Istituto di Fisiologia Umana II, Universit[grave]a degli Studi, I-20133
Milano and Dipartimento di Scienze Chimiche, Universit[grave]a di Camerino,
I-62032 Camerino, Italy
APStracts 2:0045R, 1995.
The medial preoptic area (MPA), a cholinoceptive brain area devoid of
cholinergic cells, plays an important role in the regulation of
different physiological functions, particularly sleep control and
thermoregulation. To investigate the effects of the stimulation of
cholinergic receptors in this area on sleep and cortical temperature
(Tcort), carbachol (a mixed cholinergic agonist) was directly
microinjected into the MPA of freely moving rats. Carbachol (0.25 and
0.5 [mu]g, corresponding to 1.37 and 2.74 nmoles) microinjection induced
an increase in wakefulness and an inhibition of both slow wave and
desynchronized sleep phases. The temperature of the cerebral cortex
was reduced in comparison with control conditions (saline
microinjection). Sterile needle insertion and saline microinjections
induced a significant increase in Tcort, but no changes in the sleep
-wake cycle when compared to the handling of the animal. The results
suggest that: i) carbachol microinjection into the MPA can activate
an arousal generating system and affect thermoregulatory mechanisms;
ii) sleep and temperature responses may be dissociated.
Received 2 August 1994; accepted in final form 8 February 1995.
APS Manuscript Number R424-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.