Matsuki T, Ohhashi T
First Department of Physiology, Shinshu University School of Medicine, Matsumoto, Japan.
Am J Physiol. 1990 Oct;259(4 Pt 2):H1032-7. doi: 10.1152/ajpheart.1990.259.4.H1032.
Ring strips of monkey pulmonary veins precontracted with a high concentration of prostaglandin F2 alpha (PGF2 alpha) relaxed in a concentration-dependent manner in response to histamine. Treatment with mepyramine and/or famotidine attenuated the relaxation. 2-Pyridylethylamine (2PEA) and dimaprit caused relaxations in the precontracted preparations, which were inhibited by pretreatment with mepyramine and famotidine, respectively. Removal of endothelium reversed the histamine- and 2PEA-induced relaxations to dose-related contractions. On the other hand, the removal had no effect on the dimaprit-induced relaxations, which were significantly reduced by pretreatment with famotidine. Histamine-induced relaxations in the precontracted strips with endothelium in the presence and absence of famotidine were suppressed or abolished by treatment with methylene blue or hemoglobin but were unaffected by aspirin. It may be concluded that histamine-induced relaxation in monkey pulmonary veins precontracted with PGF2 alpha is mediated by H2-receptors in smooth muscle and H1-receptors in endothelium. Also, stimulation of the endothelial H1-receptors liberates an endothelium-derived relaxing factor.
预先用高浓度前列腺素F2α（PGF2α）预收缩的猴肺静脉环条，对组胺呈浓度依赖性舒张。用美吡拉敏和/或法莫替丁处理可减弱这种舒张作用。2-吡啶乙胺（2PEA）和二甲双胍在预收缩的标本中引起舒张，分别用美吡拉敏和法莫替丁预处理可抑制这种舒张。去除内皮后，组胺和2PEA诱导的舒张转变为剂量相关的收缩。另一方面，去除内皮对二甲双胍诱导的舒张无影响，而法莫替丁预处理可显著降低这种舒张。在有和没有法莫替丁的情况下，组胺在有内皮的预收缩条带中诱导的舒张，用亚甲蓝或血红蛋白处理可被抑制或消除，但不受阿司匹林影响。可以得出结论，PGF2α预收缩的猴肺静脉中组胺诱导的舒张是由平滑肌中的H2受体和内皮中的H1受体介导的。此外，刺激内皮H1受体可释放一种内皮衍生的舒张因子。
