哌唑嗪
尼卡地平
尼群地平
地尔硫卓
化学
维拉帕米
硝苯地平
效力
二氢吡啶
钙通道
肌膜
药理学
膜
钙
受体
敌手
生物化学
生物
体外
有机化学
作者
J Nishimura,Hideo Kobayashi,M Nakamura
出处
期刊:PubMed
日期:1986-03-01
卷期号:236 (3): 789-93
被引量:4
摘要
The characteristics of [3H]prazosin binding and the interaction of Ca antagonists with alpha-1 adrenoceptors in the porcine aortic membranes were investigated. The binding characteristics of [3H]prazosin, namely, the kinetics and affinity of binding, saturability, competition by adrenergic agonists and antagonists, stereoselectivity and the localization of binding sites, indicated that [3H]prazosin binds specifically to the alpha-1 adrenoceptors in the sarcolemma of porcine aortic smooth muscle cells. In the inhibition study by several Ca antagonists, the specific binding of [3H]prazosin to aortic membranes was inhibited by verapamil (Ki = 0.66 microM), D600 (Ki = 0.86 microM), nicardipine (Ki = 2.3 microM) and d-cis diltiazem (Ki = 9.8 microM). Nifedipine and nitrendipine, potent dihydropyridine Ca antagonists, only partially inhibited the [3H]prazosin binding, up to 10(-4) M. l-Cis and dl-trans diltiazem, the less potent stereoisomers as Ca channel blockers compared with the d-cis form, showed a similar and greater potency as a competitor to alpha-1 adrenoceptors, respectively. These observations indicate that verapamil, D600, nicardipine and diltiazem interact with vascular alpha-1 adrenoceptors and that the potency of these compounds as a competitor to alpha-1 adrenoceptors does not parallel their potency as Ca channel blockers.
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