Competitive interaction of amiloride and verapamil with alpha 1-adrenoceptors in vascular smooth muscle.
Competitive interaction of amiloride and verapamil with alpha 1-adrenoceptors in vascular smooth muscle.
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阿米洛利和维拉帕米与血管平滑肌中α1-肾上腺素受体的竞争性相互作用。
DOI：
10.1097/00005344-198609000-00007
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发表时间：
1986
影响因子：
3
通讯作者：
Sharma,RV
中科院分区：
文献类型：
--
作者：
Bhalla,RC;Sharma,RV
我们表征了[3H] prazosin与从牛颈动脉分离的纯化质膜的结合，并研究了Na+和Ca2+通道阻滞剂对[3H] prazosin与[α] 1肾上腺素受体结合的影响。阿米洛利和维拉帕米竞争性地抑制[3H]吡唑嗪与牛颈动脉纯化质膜的特异性结合，并呈剂量依赖性。维拉帕米和阿米洛利对[α] 1肾上腺素能受体的Ki值分别为1.04+/-0.037 [mu] M和32.6+/-0.59 [mu] M。维拉帕米（10 [mu] M）和阿米洛利（100 [mu] M）分别使[3H] prazosin结合的亲和力降低了6倍和2.7倍，但结合位点的数量没有变化。水洗后，阿米洛利和维拉帕米对[3H] prazosin结合的抑制作用可以逆转。另一种Ca2+通道阻滞剂硝苯地平和Na+通道阻滞剂呋塞米在0.1 mM浓度下没有显著抑制[3H]吡唑嗪的结合。我们的研究结果表明，除了阻断Na+和Ca2+通道外，阿米洛利和维拉帕米可能通过调节[α] 1肾上腺素能受体的亲和力来产生血管平滑肌松弛。
We have characterized [3H] prazosin binding to purified plasma membranes isolated from bovine carotid arteries and studied the effects of Na+ and Ca2+ channel blockers on [3H] prazosin binding to [alpha] 1 adrenoceptors. Amiloride and verapamil competitively inhibited the specific binding of [3H] prazosin to purified plasma membranes isolated from bovine carotid artery in a dose dependent manner. The Ki values of verapamil and amiloride for [alpha] 1 adrenergic receptor were 1.04+/-0.037 [mu] M and 32.6+/-0.59 [mu] M, respectively. Verapamil (10 [mu] M) and amiloride (100 [mu] M) caused a 6 fold and 2.7 fold decrease in affinity of [3H] prazosin binding, respectively, with no change in the number of binding sites. The inhibition of [3H] prazosin binding by amiloride and verapamil could be reversed after the membranes were washed. Another Ca2+ channel blocker, nifedipine, and a Na+ channel blocker, furosemide, did not significantly inhibit [3H] prazosin binding up to 0.1 mM concentrations. Our results suggest that amiloride and verapamil may produce vascular smooth muscle relaxation by modulating [alpha] 1 adrenoceptor affinity in addition to blocking Na+ and Ca2+ channels, respectively.