A response to isoprenaline unrelated to alpha- and beta-adrenoceptor agonism.
A response to isoprenaline unrelated to alpha- and beta-adrenoceptor agonism.
复制标题
对异丙肾上腺素的反应与α-和β-肾上腺素受体激动无关。
DOI：
10.1111/j.1476-5381.1987.tb11262.x
复制
发表时间：
1987
影响因子：
7.3
通讯作者：
Clarke,DE
中科院分区：
文献类型：
--
作者：
Bond,RA;Clarke,DE
β-肾上腺素能受体激动作用可能解释α 2-肾上腺素能受体拮抗剂和苯乙胺类激动剂之间缺乏竞争性拮抗作用的假设在电场刺激的豚鼠回肠中进行了测试。β-肾上腺素受体激动剂异丙肾上腺素，被用作苯乙胺和抑制'抽搐'反应诱发的胆碱能刺激进行了测量。在咪唑克生（3 μ M）的存在下，阻断抑制性α 2-肾上腺素受体，普萘洛尔（0.1至5.0 μ M）未能对异丙肾上腺素起竞争性作用。异丙肾上腺素反应完全抵抗抑制普萘洛尔。由于豚鼠回肠中不存在抑制性α 1-肾上腺素受体，因此假定存在与目前定义的α-和β-肾上腺素受体不同的识别位点。苯乙胺类激动剂在该位点的激动作用可能解释了它们不能与α-和β-肾上腺素受体拮抗剂竞争作用。
The hypothesis that beta-adrenoceptor agonism might explain a reported lack of competitive antagonism between alpha 2-adrenoceptor antagonists and agonists of the phenylethylamine class was tested in the electrically field stimulated ileum of the guinea-pig. The beta-adrenoceptor agonist, isoprenaline, was used as the phenylethylamine and inhibition of 'twitch' response evoked by cholinergic stimulation was measured. In the presence of idazoxan (3 microM), to block inhibitory alpha 2-adrenoceptors, propranolol (0.1 to 5.0 microM) failed to act competitively toward isoprenaline. Isoprenaline responses totally resistant to inhibition by propranolol were obtained. As inhibitory alpha 1-adrenoceptors are absent from guinea-pig ileum, a recognition site distinct from the currently defined alpha- and beta-adrenoceptors is postulated. Agonism by phenylethylamine based agonists at this site may explain their inability to act competitively with alpha- and beta-adrenoceptor antagonists.