内皮素对大鼠离体肺动脉的作用及其机制的初步探讨

本实验利用生物测定法观察了内皮素引起离体大鼠肺动脉收缩的作用,初步探讨了异搏定和具有较强超氧化物阴离子清除作用的764-3及去甲二氢愈创木脂酸、消炎痛、乙胺嗪、酚妥拉明、心得安、阿托品、ketaserin tartrate对此收缩反应的影响。结果表明:内皮素使离体大鼠肺动脉强烈收缩,这一反应部分依赖于细胞外钙的内流,与超氧化物阴离子的产生和释放也有关。花生四烯酸代谢、肾上腺素能受体、5-羟色胺受体、胆碱能受体在内皮素的作用过程中可能不起作用。

PRELIMINARY STUDY ON THE EFFECT OF ENDOTHELIN ON THE CONTRACTION OF ISOLATED RAT PULMONARY ARTERY AND ITS MECHANISM

Experiment was performed on the rings of right pulmonary artery (PA) taken from male Wistar rats. Each ring was suspended in an organ bath (37 degrees C) containing Krebs solution, gassed with 95% O2-5% CO2 (pH7.40). The changes of vascular tension were measured. The contraction of PA to endothelin (ET) (10(-9) mol/L) and the effects of 764-3 (50, 100, 200, 300 micrograms/ml as a scavenger of superoxide anion), verapamil (3 x 10(-6) mol/L) NDGA, indomethacin, atropine, phentolamine, propranolol, ketanserin tartrate and diethylcarbamazine on the ET-induced contraction were investigated. The results indicated that ET can induce a potent and sustained contraction of PA, inhibited by verapamil and 764-3, but unaffected by inhibitors of cyclooxygenase, lipoxygenase, leukotrienes systhetase or adrenergic, serotonergic, cholinergic receptors. It is suggested that the influx of extracellular Ca2+ and the production of superoxide anion might be involved in the ET-induced contraction. Arachidonate metabolism and receptors mentioned above probably didn't participate in the responses.