PROLONGED ENHANCEMENT OF REM-SLEEP PRODUCED BY CARBACHOL MICROINJECTION INTO THE AMYGDALA

THE effect on sleep organization of carbachol microinjected into diffe rent amygdaloid nuclei was analysed in 12 cats. Single carbachol doses of 8 mu g in 0.50 mu l saline were delivered unilaterally or bilatera lly into the central, basal, lateral or basolateral amygdaloid nucleus . Carbachol administration into the central nucleus induced a prolonge d (5 days) enhancement of both REM sleep and its preceding slow wave s leep episodes with PGO waves (sommeil phasique a ondes lentes, SPHOL), which was more pronounced following bilateral than unilateral carbach ol administration. However. neither SPHOL nor REM sleep changes were p roduced by administration of carbachol into the other amygdaloid nucle i. We conclude that cholinergic activation of the central amygdaloid n ucleus produces a long-term facilitation of REM sleep occurrence.