SLEEP AND WAKING DURING ACUTE HISTAMINE-H-3 AGONIST BP-2.94 OR H-3 ANTAGONIST CARBOPERAMIDE (MR-16155) ADMINISTRATION IN RATS

The present study evaluated the effects of histamine H-3 receptor agon ist BP 2.94 or H-3 receptor antagonist carboperamide (MR 16155) given by oval route on sleep and waking in rats surgically prepared for long -term recordings. BP 2.94 produced a significant increase of slow-wave sleep (SWS) that teas related to slight decreases of waking, light sl eep, and REM sleep. Carboperamide significantly increased waking and d ecreased SWS and REM sleep. Pretreatment with carboperamide prevented the effect of BP 2.94 on SWS. It is suggested that the effects of BP 2 .94 or carboperamide on sleep and waking could depend on changes in th e availability of histamine at the postsynaptic H-1 receptor. Alternat ively, activation or blockade of the H-3 heteroreceptors found in the central catecholamine, indolamine, and acetylcholine nel ve endings co uld inhibit or increase the release of noradrenaline, serotonin, dopam ine, and acetylcholine. This would secondarily result in changes of sl eep variables.