Binding of [3H]dihydroazapetine to alpha-adrenoreceptor-related proteins from rat vas deferens.
Binding of [3H]dihydroazapetine to alpha-adrenoreceptor-related proteins from rat vas deferens.
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[3H]二氢氮杂哌丁与来自大鼠输精管的α-肾上腺素受体相关蛋白的结合。
DOI：
10.1073/pnas.73.8.2730
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发表时间：
1976
影响因子：
11.1
通讯作者：
P. Patil
中科院分区：
文献类型：
--
作者：
R. Ruffolo;J. Fowble;D. Miller;P. Patil
强效的α -肾上腺素受体阻滞剂阿扎铂已被氚气催化还原成[3H]二氢阿扎铂。[3H]二氢氮氮定保留了阻断α -肾上腺素受体的显著能力，并已被用作配体来研究含有大鼠输精管膜片段的亚细胞片段中的受体。[3H]二氢氮扎铂的特异性结合迅速达到平衡，并且具有可逆和饱和的解离常数，与药理学确定的解离常数相似。结合能力约为40 pmol/mg的蛋白质。所有测试的α -肾上腺素能阻滞剂都能抑制特异性结合。高浓度的阿异诺尔、阿托品或氯苯那敏没有效果。此外，咪唑啉类的所有α -肾上腺素能激动剂在低浓度下都能抑制结合，而索烯醇或氨甲酰胆碱则没有。完整组织中受体的阻断或刺激与[3H]二氢氮扎铂与亚细胞部分结合的抑制之间存在良好的相关性（r=0.84）。这些发现表明，该部分含有α -肾上腺素受体相关蛋白。α -肾上腺素能激动剂在结构上与去甲肾上腺素相关，引起立体选择性结合增加，有利于(-)-异构体，可能反映了受体蛋白不同结合位点的变构相互作用。对于结构不同的激动剂，可能存在两种不同的结合模式。
The potent alpha-adrenoreceptor blocking agent, azapetine, has been catalytically reduced with tritium gas to form [3H]dihydroazapetine. [3H]Dihydroazapetine retains significant ability to block alpha-adrenoreceptors and has been used as a ligand to study the receptor in a subcellular fraction containing membrane fragments from rat vas deferens. Specific binding of [3H]dihydroazapetine rapidly reaches equilibrium and is also reversible and saturable with a dissociation constant similar to that determined pharmacologically. The binding capacity is approximately 40 pmol/mg of protein. All alpha-adrenergic blockers tested were able to inhibit specific binding. High concentrations of alprenolol, atropine, or chlorpheniramine had no effect. In addition, all alpha-adrenergic agonists of the imidazoline class inhibit binding in low concentrations, whereas soterenol or carbamylcholine did not. There is good correlation (r=0.84) between blockade or stimulation of the receptor in intact tissues and inhibition of binding of [3H]dihydroazapetine to the subcellular fraction. These findings suggest that the fraction contains alpha-adrenoreceptor-related proteins. Alpha-adrenergic agonists structurally related to norepinephrine caused a stereoselective increase in binding in favor of the (-)-isomer, possibly reflecting an allosteric interaction at a different binding site on the receptor protein. The possibility of two different modes of binding for structurally dissimilar agonists is suggested.