VASODILATOR RESPONSE OF CORONARY SMOOTH-MUSCLE TO THE SYMPATHETIC COTRANSMITTERS NORADRENALINE AND ADENOSINE 5'-TRIPHOSPHATE

被引:33
作者
CORR, L [1 ]
BURNSTOCK, G [1 ]
机构
[1] UNIV LONDON UNIV COLL,CTR NEUROSURG,LONDON WC1E 6BT,ENGLAND
关键词
NORADRENALINE; ADENOSINE 5'-TRIPHOSPHATE; ADENOSINE; CORONARY ARTERY;
D O I
10.1111/j.1476-5381.1991.tb12432.x
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
1 Vasodilator and vasoconstrictor responses to noradrenaline (NA), adenosine and adenosine 5'-triphosphate (ATP) were examined in isolated ring segments of the left anterior descending coronary artery of the rabbit in the absence of endothelium. 2 NA caused dose-dependent relaxation of potassium-constricted vessels in the absence of beta-adrenoceptor blockade, with a pD2 of 5.96 +/- 0.21. This was inhibited by 1-mu-M propranolol. Constrictor responses of vessels at baseline tension were only seen at concentrations greater than 1 mM, and reached a maximum of 6% of the contraction to 30 mM KCl. 3 ATP caused relaxation of the potassium-constricted ring segments in a dose-dependent manner, although a transient constriction often preceded the relaxation. Adenosine was equipotent with ATP in producing relaxation; this was significantly inhibited by the P1-purinoceptor antagonist, 8-phenyltheophylline (8-PT). The responses to ATP were little affected by 8-PT, indicating that ATP was not acting through breakdown to adenosine. At basal tone, ATP produced transient vasoconstriction only at concentrations greater than 0.1 mM, reaching a maximum of 38% of the contraction to 30 mM KCl. 4 We conclude that in the rabbit coronary artery both NA and ATP produce vasodilatation by a direct action on the smooth muscle.
引用
收藏
页码:337 / 342
页数:6
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