加压素(4-8)对大鼠脑内Ca^(2+)/CaM依赖的蛋白激酶Ⅱ自身磷酸化的影响

EFFECT OF AVP(4-8) ADMINISTRATION ON Ca^(2+)/CaM-DEPENDENT PROTEIN KINASE Ⅱ AUTOPHOSPHORYLATION IN RAT BRAIN

大鼠皮下注射加压素（AVP）（4-8）1h后，大脑皮层中Ca2+／CaM依赖的蛋白激酶Ⅱ（CaMKⅡ）自身磷酸化程度与对照组比较增高192％，P＜0.001；海马中增高40％，P＜0．05。CaMKⅡ的自身磷酸化程度依赖于Ca2+及CaM的浓度。在用抗CaMKⅡα单克隆抗体对给药1h组样品和对照组样品进行免疫印迹检测时，发现皮下注射AVP（4-8）1h后，大脑皮层中CaMKⅡα亚基的蛋白量没有明显差异。AVP（4－8）的拮抗剂ZDC（C）PR可以明显阻断AVP（4-8）的作用，表明AVP（4-8）刺激CaMKⅡ的活化是通过受体介导的信号转导过程。

The extent increase of Ca2+/CaM-dependent protein kinase Ⅱ (CaMK Ⅱ)autophosphorylation in various brain regions of rat reached a maximum value, one hour after s. c. drinistration of AVP(4-8). The increase in the cortex amounted to 192% of the control (P< 0.001 ), whi1e in the hippocampus only 40% (P<0.05). The autophosphorylation of CaMKⅡ was dependent on both Ca2+ and CaM. Western blotting with anti-CaMKⅡa monoclonal antibody showed that the content of CaMK Ⅱ α in cortex did not show detectable change in 1 h as compared to the control group.ZDC(C)PR, an antagonist of AVP(4-8), markedly blocked the effect of AVP(4-8), suggesting that AVP (4-8) stimulated CaMK Ⅱautophosphorylation is mediated through its receptor.