THE EFFECT OF CHOLINERGIC AND OTHER PHARMACOLOGIC AGENTS ON BRAIN MONOPHOSPHOINOSITIDE TURNOVER IN VIVO

¹ Department of Pharmacology, University of Chicago, Chicago, Illinois

The effect of various parasympathomimetic and other drugs on brain monophosphoinositide turnover was studied in vivo. Parathion increased brain acetylcholine levels by 95% and produced a concomitant increase of 29% in brain monophosphoinositide turnover. Pilocarpine in doses of 2 mg/kg or greater increased monophosphoinositide turnover by 38%. This effect of pilocarpine was abolished by pretreatment with the atropine, which by itself had no effect on monophosphoinositide turnover. Amphetamine did not increase monophophoinositide turnover, and peripheral cholinergic stimulation produced by bethanechol was also without effect. Pentobarbital was found to decrease monophosphoinositide turnover by 21% in the presence of a 28% increase in brain acetylcholine levels. These results demonstrate that central cholinergic stimulation in rats is accompanied by an increase in brain monophosphoinositide turnover in vivo. This effect appears to be of a specifically cholinergic nature.