Yamada S, Harada Y, Nakayama K
Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Eur J Pharmacol. 1988 Sep 13;154(2):203-8. doi: 10.1016/0014-2999(88)90099-4.
The receptor sites for dihydropyridine calcium channel antagonists in porcine coronary artery were characterized with [3H]nitrendipine (NTD), and were compared with those in the thoracic aorta. Specific [3H]NTD binding in the coronary artery and aorta was saturable, reversible and of high affinity. These sites showed a pharmacological specificity and stereoselectivity characteristic of the receptor sites for dihydropyridine calcium channel antagonists. The pharmacological potencies of nitrendipine, nifedipine, nisoldipine, (+)-PN 200-110 and (-)-PN 200-110 in the isolated porcine coronary artery correlated well with their potencies in competing for [3H]NTD binding sites. The Hill coefficients for the competition curves for these antagonists in the porcine coronary artery and aorta were close to one. Verapamil partially inhibited specific [3H]NTD binding in both tissues. The [3H]NTD binding was increased by Mg2+ and Ca2+ but was markedly reduced by EDTA. Thus, the present study has shown that [3H]NTD selectively labels the pharmacologically relevant dihydropyridine receptors in the porcine coronary artery and that there is no significant difference between the binding characteristics of the receptor sites in the coronary artery and aorta of pigs.
用[3H]尼群地平（NTD）对猪冠状动脉中二氢吡啶钙通道拮抗剂的受体位点进行了表征，并与胸主动脉中的受体位点进行了比较。冠状动脉和主动脉中特异性[3H]NTD结合具有饱和性、可逆性和高亲和力。这些位点表现出二氢吡啶钙通道拮抗剂受体位点的药理学特异性和立体选择性。尼群地平、硝苯地平、尼索地平、（+）-PN 200-110和（-）-PN 200-110在离体猪冠状动脉中的药理效力与其竞争[3H]NTD结合位点的效力密切相关。这些拮抗剂在猪冠状动脉和主动脉中的竞争曲线的希尔系数接近1。维拉帕米部分抑制了两种组织中特异性[3H]NTD结合。[3H]NTD结合因Mg2+和Ca2+而增加，但因EDTA而显著降低。因此，本研究表明，[3H]NTD选择性标记猪冠状动脉中与药理学相关的二氢吡啶受体，并且猪冠状动脉和主动脉中受体位点的结合特性之间没有显著差异。
