α-Methyl analogues of acetylenic amines as striatal muscarinic antagonists

Abstract

Abstract The effect of acetylenic amines, with or without α-methyl substitution, on striatal acetylcholine (ACh) concentration in rats was investigated. Oxotremorine, oxotremorine-1, and U-77053 (trimethyl (4-(1-pyrrolidinyl)-2 butynyl)-urea), the unsubstituted amines, increased striatal ACh concentration. On the other hand, the corresponding α-methyl substituted analogues, α-methyl-oxotremorine, BM-5, and α-methyl U-77053, decreased the concentration of ACh in the striatum. The results indicate that substitution of α-methyl in acetylenic amines converts compounds from agonists to antagonists for striatal muscarinic receptors.