脓毒血症时大鼠心肌G蛋白的变化

ALTERATION OF CARDIAC G PROTEINS DURING SEPSIS

目的：研究脓毒血症时大鼠心肌Ｇ蛋白的变化。方法：免疫印迹法测定大鼠心肌细胞膜Ｇｓα、Ｇｉα２和Ｇｉα３的含量，放射免疫法测定各组心肌腺苷酸环化酶的活性。结果：脓毒血症时Ｇｓα表达无明显变化。脓毒血症晚期Ｇｉα２和Ｇｉα３含量分别升高５３．５％（Ｐ＜０．０５）和６３．７％（Ｐ＜０．０１）。基础及Ｇｐｐ（ＮＨ）Ｐ刺激的腺苷酸环化酶活性在脓毒血症晚期明显抑制。结论：大鼠心肌Ｇｉ的增加参与脓毒血症时腺苷酸环化酶信号转导系统功能障碍的发生。

Objective: Alteration of G proteins in rat myocardium during sepsis was studied. Methods: levels of Gsα, Giα2 and Giα3 in sarcolemma were measured by Western blot analysis. Adenyl cyclase activities in control, early or late sepsis were determined by radioimmunoassay. Results: Expressions of Gsα were unchanged during sepsis. Levels of Giα2 and Giα3 were increased by 53.5% (P<0.05) and 63.7% (P<0.01) in late sepsis compared with control group. Basal and Gpp(NH)p stimulated adendyl cyclase activities were significantly depressed in late sepsis. Conclusion: Increase of cardiac Gi may contribute to the dysfunction of adenyl cyclase signal transduction system during sepsis.