Bromberg B B, Gregory D S, Sears M L
Invest Ophthalmol Vis Sci. 1980 Feb;19(2):203-7.
Identification and characterization of beta-adrenergic receptors were attempted in particulate membrane fractions derived from isolated ciliary processes (CP) of rabbit eyes. High-affinity binding sites for 125I-hydroxybenzylpindolol (125I-HYP), a beta-adrenergic antagonist, were identified in particulate membrane fractions of homogenized CP that were recovered from discontinuous sucrose density gradients. Adenylate cyclase activity was recovered in the same fraction as the 125I-HYP binding sites. The dissociation constant of 125I-HYP for the high affinity site is 0.25 nM, with a minimum capacity of about 35 fmol/mg of protein. Adrenergic agonists and antagonists, including timolol, 1-alprenolol, d,1-propranolol, 1-isoproterenol, 1-epinephrine, and phentolamine, were examined for their ability to displace 125I-HYP from its binding site. The results were consistent with the identification of the high-affinity 125I-HYP binding sites as beta-adrenergic receptors. This is the first report which identifies by ligand binding techniques beta-adrenergic receptors in CP exclusive of iridial or other uveal tissue and supports the possibility of direct action of beta-adrenergic agents on the formation of aqueous humor.
我们尝试在从兔眼分离的睫状体（CP）获得的微粒膜组分中鉴定和表征β-肾上腺素能受体。在从间断蔗糖密度梯度回收的匀浆CP微粒膜组分中鉴定出β-肾上腺素能拮抗剂125I-羟基苄基吲哚洛尔（125I-HYP）的高亲和力结合位点。腺苷酸环化酶活性在与125I-HYP结合位点相同的组分中回收。125I-HYP对高亲和力位点的解离常数为0.25 nM，最小容量约为35 fmol/mg蛋白质。检测了肾上腺素能激动剂和拮抗剂，包括噻吗洛尔、1-阿普洛尔、d,1-普萘洛尔、1-异丙肾上腺素、1-肾上腺素和酚妥拉明，使其从结合位点取代125I-HYP的能力。结果与将高亲和力125I-HYP结合位点鉴定为β-肾上腺素能受体一致。这是第一篇通过配体结合技术在不包括虹膜或其他葡萄膜组织在内的CP中鉴定β-肾上腺素能受体的报告，并支持β-肾上腺素能药物对房水形成直接作用的可能性。
