Malta E, Raper C, Tawa P E
Br J Pharmacol. 1981 Jun;73(2):355-62. doi: 10.1111/j.1476-5381.1981.tb10429.x.
1 Noradrenaline and 28 imidazolidine (clonidine-like) and imidazoline (oxymetazoline-like) compounds with various phenyl ring substituents have been examined for their ability to inhibit responses to transmural stimulation and exogenous acetylcholine in ileal preparations from reserpine-treated guinea-pigs.2 The bathing solution contained propranolol, mepyramine, cimetidine and desipramine to preclude interference with the responses by other than the alpha-receptor-mediated actions of the compounds.3 In transmurally stimulated preparations the inhibitory response to noradrenaline is due to a combination of prejunctional alpha-adrenoceptor stimulation and a postjunctional depressant effect that does not involve adrenoceptor activation.4 Of the 28 imidazolidines and imidazolines studied, 21 inhibited transmurally elicited responses. In the various compounds studied this effect involved actions at pre- or postjunctional sites as indicated by (a) the frequency-dependence of the inhibitory response, (b) its susceptibility to blockade by alpha-receptor antagonists and (c) the relative concentrations required to inhibit responses to transmural stimulation and exogenous acetylcholine.
已对去甲肾上腺素以及28种带有不同苯环取代基的咪唑烷（类可乐定）和咪唑啉（类羟甲唑啉）化合物进行了研究，考察它们抑制利血平处理过的豚鼠回肠制剂对透壁刺激和外源性乙酰胆碱反应的能力。
浴液中含有普萘洛尔、美吡拉敏、西咪替丁和地昔帕明，以排除这些化合物的α受体介导作用以外的其他因素对反应的干扰。
在透壁刺激的制剂中，对去甲肾上腺素的抑制反应是由于节前α肾上腺素能受体刺激和节后抑制效应共同作用的结果，后者不涉及肾上腺素能受体激活。
在研究的28种咪唑烷和咪唑啉中，有21种抑制了透壁引起的反应。在所研究的各种化合物中，这种效应涉及节前或节后部位的作用，这由以下几点表明：(a)抑制反应的频率依赖性；(b)其对α受体拮抗剂阻断的敏感性；(c)抑制对透壁刺激和外源性乙酰胆碱反应所需的相对浓度。
