Methoctramine, a cardioselective muscarinic antagonist, stimulates phosphoinositide hydrolysis in rat cerebral cortex

Document Type

Journal Article

Publication Date

8-22-1989

Journal

European Journal of Pharmacology

Volume

167

Issue

2

DOI

10.1016/0014-2999(89)90591-8

Keywords

Antimuscarinic agents; Brain; Methoctramine; Muscarinic receptor subtypes; Muscarinic receptors; Phosphoinositide hydrolysis

Abstract

The cardioselective muscarinic antagonist methoctramine antagonized carbamylcholine-mediated phosphoinositide (PI) hydrolysis in a concentration-dependent fashion in dissociated rat cerebrocortical cells. However, as the concentration of methoctramine was increased above 5 μM, there was a reversal of the antagonism of the PI response. In the absence of carbamylcholine, methoctramine by itself significantly increased PI hydrolysis with a maximal effect at 30 μM. Various classes of receptor antagonists, including atropine, and ion-channel blockers were unable to block methoctramine-stimulated PI hydrolysis. © 1989.

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