大鼠心肌肌浆网和核被膜ryanodine受体动力学特性的比较  

COMPARISON OF RYANODINE BINDING TO CARDIAC SARCOPLASMIC RETICULUM AND NUCLEAR ENVELOPE OF RAT

作　　者：王培勇[1] 杨军[2] 董林旺[2] 庞永政[2] 唐朝枢[2] 

机构地区：[1]第三军医大学病理生理教研室,重庆400038 [2]北京大学第一医院心血管病研究所,北京100034

出　　处：《中国应用生理学杂志》2002年第1期43-46,共4页Chinese Journal of Applied Physiology

基　　金：国家自然科学基金资助课题 ( 3970 0 2 0 0;39870 392 )

摘　　要：目的 :观察大鼠心肌浆网 (sarcoplasmicreticulum ,SR)和核被膜 (nuclearenvelope ,NE)ryanodine受体 (RyR)与配体结合特点及其蛋白质磷酸化调节。方法 :采用差速和等密度梯度离心分离心肌SR和NE ,用放射受体分析法研究RyR的特征。结果 :NE上存在高亲和力RyR ,其最大结合 (Bmax)为SRRyR的 1.7% ,解离常数 (Kd)为SR的6 0 %。分别用PKA和PKC磷酸化后 ,SR上该受体的Bmax各增加 3.7和 1.2倍 ,而NE上的该受体Bmax各增加 2 .2和 3.1倍 ,Kd均无显著改变。结论 :NE上存在比SR密度低但亲和力高的RyR ,能被PKA和PKC激活 。Aim: The characteristics of ryanodine receptor in rat cardiac sarcoplasmic reticulum (SR) and nuclear envelope (NE) were studied. Methods: Velocity and isopyknic gradient centrifugation was employed to fractionate rat SR and NE. Ryanodine receptor was assayed with ryanodine saturate binding to the preparations. Results: The maximal binding (Bmax) and dissociating constant (Kd) of ryanodine receptor in rat cardiac NE were, 1.7% and 60% of those in SR respectively. Phosphorylation in vitro by PKA and PKC increased Bmax of the receptors in SR by 372% and 121%,and augmented those in NE by 221% and 306%, without any effects on Kd. Conclusion: Ryanodine receptors were present in rat myocardial NE,with lower density and higher affinity than those located in SR,which can be activated by PKA and PKC.

关 键 词：心肌 核被膜 肌浆网 RYANODINE受体 磷酸化 动力学特性 

分 类 号：R331.31[医药卫生—人体生理学] Q593.3[医药卫生—基础医学]