RESUMO
The authors studied ED50 of bethanechol on the contractilities of the smooth muscles isolated from various organs of rat under the presence of atropine (a classical competitive blocker of cholinergic muscarinic receptor) or minaprine (a newly developed antidepressant drug) to investigate the peripheral anticholinergic effect of minaprine. The results were as follow: 1) There was no significant difference between ED50 of bethanechol in the control group and that under the presence of minaprine 10⁻⁸M and 10⁻⁷M in the smooth muscles isolated from the duodenum. 2) There was no significant difference between ED50 of bethanechol in the control group and that under the presence of minaprine 10⁻⁸M and 10⁻⁷M in the smooth muscles isolated from the ascending colon. 3) There was significant difference between ED50 of bethanechol in the control group and that under the presence of minaprine 10⁻⁸M and 10⁻⁷M in the smooth muscles isolated from the urinary bladder (P<0.01) 4) There was significant difference between ED50 of the atropine 10⁻⁸ and minaprine (10⁻⁸M) in the smooth muscles isolated from the urinary bladder (P<0.05).
