[Comparison of pharmacological effects of L- and DL-n-butyl-scopolamine in rat uterus].

The affinities of L-n-butyl-scopolamine, DL-n-butyl-scopolamine and atropine for the M-cholinergic receptors of rat uterus were compared using radioligand binding assay. Results showed that the affinity of L-n-butyl-scopolamine for the M-receptors was similar to that of DL-n-butyl-scopolamine, but lower than that of atropine. In isolated rat uterus, L- and DL-n-butyl-scopolamine were found not to influence the automatic contraction but antagonize the contraction induced by acetylcholine with nearly the same PA2, although the PA2 of both compounds were still lower than that of atropine. Therefore, no difference between L- and DL-n-butyl-scopolamine in either biological activity or receptor affinity was observed.