合成α2-肾上腺素能受体激动剂对虹鳟鱼（鲑鱼）胃平滑肌条中儿茶酚胺收缩反应的拮抗样作用。

Antagonist like action of synthetic alpha 2-adrenoceptor agonists on contractile response to catecholamines in smooth muscle strips isolated from rainbow trout stomach (Salmo gairdneri).

Kitazawa T, Miyashita N, Chugun A, Temma K, Kondo H

Department of Veterinary Pharmacology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori, Japan.

Comp Biochem Physiol C Comp Pharmacol Toxicol. 1988;91(2):585-8.

Abstract

The effects of some synthetic alpha 2-adrenoceptor agonists on the mechanical activity and on contractile responses to catecholamines were examined in smooth muscle strips isolated from rainbow trout stomach. 2. Contractile responses to noradrenaline and adrenaline in the rainbow trout stomach strips were due to alpha 2-adrenoceptor activation. 3. Clonidine, p-aminoclonidine, naphazoline and guanabenz caused no mechanical response but concentration-dependently inhibited the contractile responses to noradrenaline and adrenaline without affecting the responses to acetylcholine, carbachol, 5-hydroxytryptamine and methionine-enkephalin. The order of potency was naphazoline greater than p-aminoclonidine greater than clonidine greater than guanabenz. 4. It is suggested that in the smooth muscle preparation of the trout stomach, some synthetic compounds (clonidine, p-aminoclonidine, naphazoline and guanabenz), which act on mammalian preparations as alpha 2-adrenoceptor agonists, show an antinoradrenaline (-adrenaline) effect; those compounds can be classified as alpha 2-adrenoceptor antagonists.

摘要

研究了一些合成α2-肾上腺素能受体激动剂对从虹鳟鱼胃分离出的平滑肌条机械活性以及对儿茶酚胺收缩反应的影响。2. 虹鳟鱼胃条对去甲肾上腺素和肾上腺素的收缩反应是由于α2-肾上腺素能受体激活所致。3. 可乐定、对氨基可乐定、萘甲唑啉和胍那苄未引起机械反应，但浓度依赖性地抑制了对去甲肾上腺素和肾上腺素的收缩反应，而不影响对乙酰胆碱、卡巴胆碱、5-羟色胺和甲硫氨酸脑啡肽的反应。效力顺序为萘甲唑啉＞对氨基可乐定＞可乐定＞胍那苄。4. 提示在虹鳟鱼胃的平滑肌制剂中，一些在哺乳动物制剂中作为α2-肾上腺素能受体激动剂起作用的合成化合物（可乐定、对氨基可乐定、萘甲唑啉和胍那苄）表现出抗去甲肾上腺素（-肾上腺素）作用；这些化合物可归类为α2-肾上腺素能受体拮抗剂。