Aksulu H E, Ercan Z S, Türker R K
Agents Actions. 1979 Dec;9(5-6):461-6. doi: 10.1007/BF01968111.
Histamine, dimaprit and impromidine caused a relaxation on the isolated cat tracheal muscle contracted by acetylcholine or serotonin. Mepyramine partially inhibited the relaxing effect of histamine without altering that of impromidine and dimaprit. Both impromidine and dimaprit produced a dose-dependent fall in perfusion pressure of the isolated perfused guinea-pig lung while histamine has a pressor effect in this preparation which reversed into a depressor one in the presence of mepyramine. Both dimaprit and impromidine also produced a fall in perfusion pressure and urine flow of the isolated perfused rabbit kidney. A rapid tachyphylaxis developed to the effect of impromidine in the kidney but not to dimaprit. A cross-tachyphylaxis was also observed between impromidine and dimaprit. The agonistic potency of impromidine was found to be very much higher than histamine and dimaprit. Metiamide has a competitive inhibitory effect against impromidine and dimaprit on the isolated perfused lung, kidney and tracheal muscle. It was concluded that impromidine is a very potent pure histamine H2-receptor agonist when compared with histamine and dimaprit on the investigated tissues.
组胺、二甲双胍和英普咪定可使由乙酰胆碱或5-羟色胺引起收缩的离体猫气管肌肉松弛。美吡拉敏部分抑制组胺的松弛作用，但不改变英普咪定和二甲双胍的松弛作用。英普咪定和二甲双胍均可使离体灌注豚鼠肺的灌注压呈剂量依赖性下降，而组胺在此制剂中具有升压作用，在美吡拉敏存在时则转变为降压作用。二甲双胍和英普咪定还可使离体灌注兔肾的灌注压和尿流量下降。对英普咪定在肾脏中的作用迅速产生快速耐受性，但对二甲双胍则无此现象。在英普咪定和二甲双胍之间也观察到交叉快速耐受性。发现英普咪定的激动效力远高于组胺和二甲双胍。甲硫米特对英普咪定和二甲双胍在离体灌注肺、肾和气管肌肉上具有竞争性抑制作用。得出的结论是，与组胺和二甲双胍相比，在研究的组织上，英普咪定是一种非常有效的纯组胺H2受体激动剂。
