The effects of adrenaline, noradrenaline and isoprenaline on inhibitory α‐ and β‐adrenoceptors in the longitudinal muscle of the guinea‐pig ileum
The effects of adrenaline, noradrenaline and isoprenaline on inhibitory α‐ and β‐adrenoceptors in the longitudinal muscle of the guinea‐pig ileum
复制标题
肾上腺素、去甲肾上腺素和异丙肾上腺素对豚鼠回肠纵肌抑制性α和β肾上腺素受体的影响
DOI：
--
复制
发表时间：
1970
影响因子：
7.3
通讯作者：
A. J. Watt
中科院分区：
文献类型：
--
作者：
H. Kosterlitz;R. Lydon;A. J. Watt
1用回肠段和肌间神经丛-纵肌标本，分析肾上腺素、去甲肾上腺素和异丙肾上腺素对纵肌对乙酰胆碱或电刺激、同轴刺激或场刺激收缩反应的抑制作用。2肾上腺素、去甲肾上腺素和异丙肾上腺素对乙酰胆碱引起的收缩的抑制作用不受苯氧苯甲胺的影响，但可被心得安拮抗，提示肌细胞上存在β肾上腺素受体。3对电刺激的反应可被肾上腺素或去甲肾上腺素抑制，而异丙肾上腺素仅部分抑制。心得安可拮抗异丙肾上腺素和去甲肾上腺素的作用，但对肾上腺素的作用无明显影响。另一方面，苯氧基苯甲胺拮抗肾上腺素的大部分作用，在一定程度上拮抗去甲肾上腺素的作用；它通常增强异丙肾上腺素的作用。4肾上腺素或去甲肾上腺素可使电刺激诱发的乙酰胆碱输出减少，异丙肾上腺素不影响。这种抑制乙酰胆碱释放的作用可被苯氧苯甲胺拮抗，但不受心得安的影响，因此，肾上腺素和去甲肾上腺素的这种作用是由α-肾上腺素受体介导的。5推测α受体主要受循环肾上腺素的刺激，可能还受去甲肾上腺素的刺激，从而引起神经-平滑肌交界处的突触前抑制。
1 Two preparations, a segment of the ileum and the myenteric plexus‐longitudinal muscle preparation, have been used for an analysis of the inhibitory effects of adrenaline, noradrenaline and isoprenaline on the contractor responses of the longitudinal muscle to acetylcholine or to electrical, coaxial or field, stimulation. 2 Since the inhibitory effects of adrenaline, noradrenaline and isoprenaline on the acetylcholine‐induced contractions were not affected by phenoxybenzamine but were antagonized by propranolol, it is concluded that β‐adrenoceptors are present on the muscle cells. 3 The responses to electrical stimulation were suppressed by adrenaline or noradrenaline but only partly inhibited by isoprenaline. Propranolol antagonized the effect of isoprenaline and, to some extent, that of noradrenaline, but scarcely affected the action of adrenaline. Phenoxybenzamine, on the other hand, antagonized most of the effect of adrenaline and, to some extent, that of noradrenaline; it usually potentiated the effect of isoprenaline. 4 The output of acetylcholine evoked by electrical stimulation was diminished by adrenaline or noradrenaline but was not affected by isoprenaline. The depressant effect on acetylcholine release was antagonized by phenoxybenzamine but not affected by propranolol; therefore these effects of adrenaline and noradrenaline are mediated by α‐adrenoceptors. 5 It may be assumed that α‐adrenoceptors in situ are stimulated mainly by circulating adrenaline and possibly noradrenaline and thus cause a prejunctional inhibition at the nerve‐smooth muscle junction.