Baker D J, Drew G M
J Auton Pharmacol. 1981 Dec;1(5):359-65. doi: 10.1111/j.1474-8673.1981.tb00074.x.
1 We have investigated the influence of chemical sympathectomy or bilateral adrenal demedullation on vasopressor responses produced by the alpha 1-adrenoreceptor agonist, phenylephrine, and the alpha 2-adrenoreceptor agonist, M-7, in pithed rats to see whether either procedure induced selective supersensitivity to either of these compounds. 5-HT, a tryptaminergic vasopressor agent, was also used to discriminate between nonspecific change in vascular responsiveness and those mediated via alpha-adrenoreceptors. 2 Adrenal demedullation caused a slight reduction in the sensitivity to all agonists. Chemical sympathectomy significantly reduced the vasopressor responses to all doses of phenylephrine, but responses to 5-HT were unchanged. In contrast there was a tendency for responses to M-7 to be greater in sympathectomized rats than in untreated rats. 3 It is concluded that circulating adrenal medullary catecholamines do not physiologically modulate vascular alpha-adrenoreceptor function. The differential effect of chemical sympathectomy on the vasopressor responses to phenylephrine and M-7 might be explained in terms of a small increase in the ratio of vascular alpha 2 : alpha 1-adrenoreceptors, that receive a noradrenergic innervation.
我们研究了化学性交感神经切除术或双侧肾上腺髓质剥除术对去脑大鼠由α1 -肾上腺素受体激动剂去氧肾上腺素和α2 -肾上腺素受体激动剂M - 7所产生的升压反应的影响，以观察这两种手术操作是否会诱导对这两种化合物中任一种产生选择性超敏反应。5 -羟色胺，一种色胺能升压剂，也被用于区分血管反应性的非特异性变化和通过α -肾上腺素受体介导的变化。
肾上腺髓质剥除术使对所有激动剂的敏感性略有降低。化学性交感神经切除术显著降低了对所有剂量去氧肾上腺素的升压反应，但对5 -羟色胺的反应未改变。相反，在交感神经切除的大鼠中，对M - 7的反应有比未处理大鼠更大的趋势。
得出的结论是，循环中的肾上腺髓质儿茶酚胺在生理上并不调节血管α -肾上腺素受体功能。化学性交感神经切除术对去氧肾上腺素和M - 7升压反应的不同影响，可能是由于接受去甲肾上腺素能神经支配的血管α2:α1 -肾上腺素受体比例略有增加来解释。
