北京鸭红细胞膜G—蛋白与磷酯酶C的偶联及腺苷受体的调节

GDP、GTP和GTPγS激活北京鸭红细胞膜上的磷酯酶C,在10~(-7)～10~(-4)mol/L的范围内,使磷酸肌醇产量增加。其中GTPγS作用最强,分别使IP_2和IP_3增强550％和580％。GTP与GDP的效力相近,使IP_2增加140％和150％;IP_3增加230％和330％。A-嘌呤能受体激动剂6-N-cyclohe-xyladenosine(CHA)对抗ATP通过P-嘌呤能受体激活的磷酯酶C,使其活性下降60％。CHA的这种作用可被其特异拮抗剂8-cyclopentyl-1,3-dimethylxanthine对抗。以上结果表明鸭红细胞是研究受体、G-蛋白及磷酯酶C偶联的良好模型。表明不同嘌呤能受体在调节磷酯酶C中的相反作用。

The Coupling of G-Protein and Phospholipase C in Peking Duck Erythrocytes Membrane and the Regulation of Adenine Receptors

The activity of phosphatydylinositol-specific phospholipase C was stimulated by GTP, GDP and GTPyS in the 3H-inositol labelled membrane preparation of Beijing duck erythrocytes. The production of 3H-inostol phosphates were increased after treated with those guanine nucleotide at concentrations ranged from 10~7 mol/L to 10-4mol/L. Among them GTPYS was the most effective, it increased IP2 and IP3 by 550% and 580%, respectively. The increase of IP2 caused by CT P and GDP were 140% and 150%, respectively; and the increase of IP3 were 230% and 330%, respectively. ATP stimulated phospholipase C through the activation of P-purinergic receptor .6-N-cyclohexyl adenosine ( CHA ) , an agonist of A-purinergic receptor, inhibited 60% of the effect of ATP, and this inhibitory effect could be reversed by 8-cyclopentyl-1, 3-dimethylxanthine, a specific antagonist of CHA.These results indicated that the regulatory effects of the different subtype of purinergic receptors on phospholipase C were different, and that Beijing duck erythrocyte is a good model for the research of the coupling of receptors, G-proteins and phospholipase C.