Moritoki H, Hosoki E, Ishida Y
Eur J Pharmacol. 1986 Jul 15;126(1-2):61-7. doi: 10.1016/0014-2999(86)90738-7.
The effect of aging on the vasodilator responses to histamine, 2-pyridylethylamine and 4-methylhistamine of ring segments of rat mesenteric arteries were investigated. The maximal extent of histamine-induced dilatation of the arteries previously contracted with norepinephrine was greatest for arteries from rats aged 2 and 8 weeks. The maximal response decreased progressively with an increase in age to 13 and 56 weeks. Arteries from 99 week old rats scarcely responded to histamine. Under these conditions, the dilatation induced by papaverine showed no change with age. The vasodilatation caused by 2-pyridylethylamine and 4-methylhistamine also decreased age dependently. The dilatation of the arteries induced by these agents was inhibited by the H1-antagonist chlorpheniramine, but not by the H2-antagonist cimetidine. Removal of the endothelium completely abolished the vasodilator effect of histamine, leaving the effect of papaverine unaffected. Hydroquinone and methylene blue reversed the dilatation induced by histamine, without affecting that caused by papaverine. These results suggest that the age-related decrease in dilatation of rat mesenteric artery in response to histamine is mainly due to a decrease in the ability of the endothelium to liberate a mediator(s).
研究了衰老对大鼠肠系膜动脉环段对组胺、2-吡啶乙胺和4-甲基组胺的血管舒张反应的影响。对于先前用去甲肾上腺素收缩的动脉，组胺诱导的最大舒张程度在2周龄和8周龄大鼠的动脉中最大。随着年龄增加至13周龄和56周龄，最大反应逐渐降低。99周龄大鼠的动脉对组胺几乎无反应。在这些条件下，罂粟碱诱导的舒张随年龄无变化。2-吡啶乙胺和4-甲基组胺引起的血管舒张也随年龄依赖性降低。这些药物诱导的动脉舒张被H1拮抗剂氯苯那敏抑制，但不被H2拮抗剂西咪替丁抑制。去除内皮完全消除了组胺的血管舒张作用，而罂粟碱的作用不受影响。对苯二酚和亚甲蓝逆转了组胺诱导的舒张，而不影响罂粟碱引起的舒张。这些结果表明，大鼠肠系膜动脉对组胺舒张反应的年龄相关性降低主要是由于内皮释放介质能力的下降。
