正丁基东莨菪碱与东莨菪碱药理作用的比较

本研究用放射配基结合法测定正丁基东莨菪碱和东莨菪碱对大鼠脑、豚鼠回肠纵长肌M胆碱受体以及大鼠脑GABA受体的亲和力。结果表明,正丁基东莨菪碱与中枢和外周M胆碱受体的亲和力均比东莨菪碱弱,而两药对GABA受体无特异性结合。正丁基东莨菪碱抗Ach收缩回肠效应也比东莨菪碱弱,表明生物效应的大小与其对受体亲和力的高低相关。用小鼠一次性训练的被动回避性反应法,观察两药对记忆获得的影响,所得资料表明,正丁基东莨菪碱阻抑记忆获得的用量至少比东莨菪碱大10～20倍。

PHARMACOLOGICAL EFFECTS OF N-BUTYL-SCOP-LAMINE IN COMPARISON WITH SCOPOLAMINE

By using radioligand binding assay method, the effects of n-butyl-scopolamine and scopolamine on the M-cholinergic receptors of rat brain and longitudinal muscle of guinea pig ileum were compared. The results showed that the affinities of n-butyl-scopolamine for central and peripheral M-receptors were lower than those of scopolamine. Both drugs, however, didn't show any effect on the GABA receptor of rat brain. The intrinsic activity of both drugs for M-receptor on isolated guinea pig ileum were also determined. Scopolamine and n-butyl-scopolamine, at concentrations of 10^-6mol/L and 10^-7～10^-8mol/L respectively, shifted the cumulative dose-response curve of Ach to the right, indicating that there is a correlation between the biological activity and the affinity for M-receptor. The two drugs were also shown to impair acquisition of memory in one trial passive avoidence responses in mice, but the efficacy of n-butyl-scopolamine was 10-20 times lower than that of scopolamine.