脑缺血及复灌中胞浆50kD蛋白反磷酸化变化

VARIATIONS OF BACK PHOSPHORYLATION OF CYTOSOL 50kD PROTEINS IN CEREBRAL ISCHEMIA/REPERFUSION

目的和方法：采用蒙古沙土鼠双侧颈总动脉结扎（ＢＣＡＯ） 前脑缺血／复灌模型，通过放射性自显影，观察脑缺血及复灌时胞浆５０ ｋＤ等蛋白在有Ｃａ２ ＋／ＣａＭ 及无Ｃａ２ ＋／ＣａＭ 两种反应条件下反磷酸化（ｂａｃｋｐｈｏｓｐｈｏｒｙｌａｔｉｏｎ） 水平的变化。结果：缺血后，总蛋白激酶介导的５０ ｋＤ蛋白反磷酸化水平逐渐下降，其中，Ｃａ２＋／ＣａＭ 依赖性蛋白激酶介导的５０ ｋＤ蛋白反磷酸化水平逐渐下降，而Ｃａ２＋／ＣａＭ 非依赖性蛋白激酶介导的５０ ｋＤ 蛋白反磷酸化水平逐渐上升；复灌后，上述变化均逐渐有所恢复。结论：脑缺血时，５０ ｋＤ 蛋白在体磷酸化水平逐渐增强，蛋白激酶活性由Ｃａ２ ＋／ＣａＭ 依赖性向Ｃａ２ ＋／ＣａＭ 非依赖性转化。

Aim and methods:By using autoradiography method, back phosphorylation of cytosol 50kD proteins was detected from mongolian gerbil cortex subjected to forebrain ischemia/reperfusion(BCAO) at various time points. Results:After ischemia, back phosphorylation of 50kD proteins gradually decreased when directed by total protein kinases; meanwhile gradually decreased when directed only by Ca 2+ /CaM dependent protein kinases, and gradually increased when directed only by Ca 2+ /CaM independent protein kinases; After reperfusion, the above changes returned towards normal level. Conclusion: During ischemia the in vivo phosphorylation level of 50 kD proteins gradually increased, and protein kinase activities changed from Ca 2+ /CaM dependent state to Ca 2+ /CaM independent state; after reperfusion all the above changes returned towards normal level.