Ferron P M, Banner W, Duckles S P
Life Sci. 1984 Nov 19;35(21):2169-76. doi: 10.1016/0024-3205(84)90518-6.
In order to explore the characteristics of alpha adrenergic receptors on cerebrovascular smooth muscle, specific binding sites for the alpha 1 adrenergic ligand, (3H) prazosin, were studied in blood vessel homogenates. No specific (3H) prazosin binding was found in either rabbit or dog cerebral arteries, but specific binding was demonstrated in the rabbit saphenous and ear arteries. In the ear artery 3H-prazosin binding was saturable with a Kd of 0.51 +/- 0.20 nM and a Bmax of 89 +/- 29 fmoles/mg protein. To confirm the adequacy of our membrane preparation, homogenates of both dog and rabbit cerebral arteries showed saturable specific binding with two different ligands: one for muscarinic receptors, 3H quinuclidinyl benzilate (QNB) and one for alpha 2 adrenergic receptors, (3H) yohimbine. The results of these studies demonstrate a lack of alpha 1 adrenergic receptors on cerebral blood vessels, confirming functional studies showing only a weak contractile response to norepinephrine.
为了探究脑血管平滑肌上α肾上腺素能受体的特征，我们在血管匀浆中研究了α1肾上腺素能配体（3H）哌唑嗪的特异性结合位点。在兔和犬的脑动脉中均未发现特异性的（3H）哌唑嗪结合，但在兔的隐动脉和耳动脉中证实有特异性结合。在耳动脉中，3H-哌唑嗪结合具有饱和性，解离常数（Kd）为0.51±0.20 nM，最大结合容量（Bmax）为89±29 fmol/mg蛋白质。为了证实我们制备的膜的适用性，犬和兔脑动脉的匀浆均显示与两种不同配体具有饱和性特异性结合：一种是用于毒蕈碱受体的[3H]（-）奎宁环基苯甲酸酯（QNB），另一种是用于α2肾上腺素能受体的（3H）育亨宾。这些研究结果表明脑血管上缺乏α1肾上腺素能受体，这证实了功能研究仅显示对去甲肾上腺素的收缩反应较弱。
