文章基本信息

标题：Assessment of Antihistaminic and Antimuscarinic Effects of Optical Isomers of Ephedrine and Methylephedrine by Receptor Binding Assay in Guinea Pig Ileal Muscle
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作者：Toru KAWASUJI ; Katsuo KOIKE ; Haruo SAITO 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：1996
卷号：19
期号：10
页码：1307-1310
DOI：10.1248/bpb.19.1307
出版社：The Pharmaceutical Society of Japan
摘要：Effects of optical isomers of ephedrine (EPH) and methylephedrine (MEP) on histamine H₁-receptors and muscarinic receptors in guinea pig ileal muscle were investigated by radioligand binding assay and by measuring the mechanical response to histamine and acetylcholine. EPH and MEP inhibited the specific binding of [³H]mepyramine and [³H]quinuclidinyl benzilate (QNB) to microsomal fractions prepared from this tissue. The rank order of inhibitory potency of [³H]mepyramine and [³H]QNB binding was d->l-isomer and l->d-isomer, respectively. Furthermore, the rank order of antagonistic potency in the mechanical response was the same as that in the binding study. d-MEP competitively antagonized histamine-induced contration (pA₂ value; 5.14). These results suggest that each isomer of EPH and MEP has a distinct affinity for histamine H₁-receptors and muscarinic receptors in guinea pig ileal muscle. The antihistaminic and antimuscarinic activity of these compounds may be largely attributed to competition at receptor sites. In addition, it is suggested that d-MEP exhibits a competitive antagonist activity for the histamine H₁-receptor.
关键词：methylephedrine;ephedrine;optical isomer;receptor binding;[3H]mepyramine;[3H]quinuclidinyl benzilate