兔虹膜和睫状体中血小板活化因子特异性结合位点的表征

Characterization of specific binding sites for PAF in the iris and ciliary body of rabbit.

作者信息

Domingo M T, Chabrier P E, Van Delft J L, Verbeij N L, Van Haeringen N J, Braquet P

机构信息

Institut Henri Beaufour LES ULIS, France.

出版信息

Biochem Biophys Res Commun. 1989 Apr 14;160(1):250-6. doi: 10.1016/0006-291x(89)91648-3.

DOI:10.1016/0006-291x(89)91648-3

PMID:2540746

Abstract

The protective effect exerted by BN 52021 a specific PAF-receptor antagonist in experimentally induced ocular inflammatory disorders led us to investigate the possible presence of specific receptors for PAF in rabbit iris and ciliary body. Two classes of PAF binding sites were found in isolated iris and ciliary process of pigmented rabbit eyes: a high affinity site Kd1 congruent to 4.9 +/- 0.47 nM, Bmax1 congruent to 3.17 +/- 0.50 pmoles/mg protein, a low affinity sites Kd2 congruent to 11.6 +/- 0.33 nM, Bmax2 congruent to 12.46 +/- 2.3 pmoles/mg protein for iris. The specific binding was not affected by lyso-PAF the biologically inactive precursor and metabolite of PAF, up to 10(-6) M; inhibition by unlabelled PAF demonstrated a biphasic curve partially antagonized by BN 52021. The present results demonstrate the presence of specific binding sites for PAF in rabbit eyes which could mediate the action of this mediator in eye inflammatory processes and explain the protective effect observed with BN 52021.

摘要

特定血小板活化因子（PAF）受体拮抗剂BN 52021在实验性诱导的眼部炎症疾病中发挥的保护作用，促使我们研究兔虹膜和睫状体中PAF特异性受体的可能存在情况。在有色家兔眼睛的离体虹膜和睫状体中发现了两类PAF结合位点：对于虹膜，一类高亲和力位点Kd1约为4.9±0.47 nM，Bmax1约为3.17±0.50 pmol/mg蛋白质；一类低亲和力位点Kd2约为11.6±0.33 nM，Bmax2约为12.46±2.3 pmol/mg蛋白质。高达10^(-6) M的PAF生物无活性前体和代谢物溶血PAF对特异性结合没有影响；未标记的PAF的抑制作用呈现双相曲线，且被BN 52021部分拮抗。目前的结果表明兔眼中存在PAF特异性结合位点，这些位点可能介导该介质在眼部炎症过程中的作用，并解释了使用BN 52021所观察到的保护作用。