Rubanyi G, Vanhoutte P M
J Cardiovasc Pharmacol. 1985 Jan-Feb;7(1):139-44. doi: 10.1097/00005344-198501000-00023.
Experiments were designed to investigate the importance of the endothelium in relaxation of isolated coronary arteries caused by beta-adrenoceptor agonists or adenosine. Rings of canine left circumflex coronary arteries were suspended for isometric tension recording in organ chambers filled with physiological salt solution. Norepinephrine, isoproterenol, adenosine, acetylcholine, and sodium nitroprusside caused relaxations of control rings contracted with prostaglandin F2 alpha or KCl. The relaxations to all substances tested were relatively smaller during contractions evoked by KCl than those caused by prostaglandin F2 alpha. Mechanical removal of the endothelium abolished the relaxations caused by acetylcholine, reduced those caused by the catecholamines and adenosine, and did not affect the relaxations to sodium nitroprusside during contractions to prostaglandin F2 alpha. Endothelium-removal did not affect relaxations to beta-adrenergic agonists or adenosine during contractions to KCl or after pretreatment of the arteries with indomethacin. Indomethacin did not affect responses to acetylcholine or sodium nitroprusside, but augmented those in response to beta-adrenoceptor stimulation and adenosine. These results suggest that the endothelial cells of the canine coronary artery produce a signal in response to beta-adrenergic agonists and adenosine, which facilitates the direct inhibitory action of these substances on vascular smooth muscle.
实验旨在研究内皮细胞在β-肾上腺素能激动剂或腺苷引起的离体冠状动脉舒张中的重要性。将犬左旋冠状动脉环悬挂于充满生理盐溶液的器官浴槽中以记录等长张力。去甲肾上腺素、异丙肾上腺素、腺苷、乙酰胆碱和硝普钠可使预先用前列腺素F2α或氯化钾收缩的对照环舒张。在由氯化钾诱发的收缩过程中，所有受试物质引起的舒张幅度均比由前列腺素F2α引起的舒张幅度相对较小。机械去除内皮细胞可消除乙酰胆碱引起的舒张，减少儿茶酚胺和腺苷引起的舒张，并且在前列腺素F2α收缩期间不影响对硝普钠的舒张反应。在氯化钾收缩期间或用吲哚美辛预处理动脉后，去除内皮细胞不影响对β-肾上腺素能激动剂或腺苷的舒张反应。吲哚美辛不影响对乙酰胆碱或硝普钠的反应，但增强对β-肾上腺素能刺激和腺苷的反应。这些结果表明，犬冠状动脉的内皮细胞在对β-肾上腺素能激动剂和腺苷的反应中产生一种信号，该信号促进这些物质对血管平滑肌的直接抑制作用。
