Todorov S, Janiec W, Sliwinski L, Folwarczna J
Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Acta Physiol Pharmacol Bulg. 1989;15(2):13-7.
Experiments were performed to study in situ the effects of histamine and some H1- or H2-agonists and antagonists on the contractions of the rat mesenteric methaarterioles (RMMA) induced by 0.6 nM noradrenaline (NA) applied locally or by electrical stimulation (ES). All drugs tested (cimetidine--300 nM, the others --30 nM) were also applied locally 30 s before the contractile stimulus. NA and ES strongly contracted the blood vessels. Of all drugs studied only diphenhydramine (DPH) evoked a slight contraction of RMMA. Histamine markedly inhibited the contractile responses to NA and ES. Similar effects were exerted by 2-(2-aminoethyl)thiazole (2-AET) its inhibitory action on the ES-induced contractions being weaker than that of histamine. Dimaprit (DMP) only tended to inhibit the RMMA contractions. DPH abolished the NA-induced contractions while cimetidine (CIM) did not change the effects of NA and ES. The results suggest that H1-receptors are mainly involved in the modifying action of histaminergic drugs on the adrenergic neurotransmission in RMMA.
进行实验以原位研究组胺及一些H1或H2激动剂和拮抗剂对局部应用0.6 nM去甲肾上腺素（NA）或电刺激（ES）诱导的大鼠肠系膜微动脉（RMMA）收缩的影响。所有测试药物（西咪替丁——300 nM，其他药物——30 nM）也在收缩刺激前30秒局部应用。NA和ES强烈收缩血管。在所有研究的药物中，只有苯海拉明（DPH）引起RMMA轻微收缩。组胺显著抑制对NA和ES的收缩反应。2-(2-氨基乙基)噻唑（2-AET）也有类似作用，其对ES诱导收缩的抑制作用比组胺弱。二甲双胍（DMP）仅倾向于抑制RMMA收缩。DPH消除了NA诱导的收缩，而西咪替丁（CIM）未改变NA和ES的作用。结果表明，H1受体主要参与组胺能药物对RMMA中肾上腺素能神经传递的调节作用。
