严重烧伤早期心肌细胞动作电位和ATP酶活性的变化

Changes of Action Potentials of Myocardiocytes and ATPase Activity After Early Serious Burn Injury in Rats.

为研究严重烧伤早期心肌细胞动作电位 (AP)和ATP酶 (ATPase)活性的变化 ,用玻璃微电极记录大鼠离体心室乳头肌细胞AP ,用差速离心和蔗糖密度梯度离心分离心肌细胞膜 ,用钼蓝比色定磷法测定总ATPase、Mg2 + ATPase和Na+ K+ ATPase活性。结果 :与对照组相比 ,①烧伤后各组静息电位、AP振幅和 0相最大去极化电位均降低 ,以伤后 8h最显著 ,分别为 - 6 4± 2vs - 87± 2mV ,88.4± 0 .0 5vs 12 3.1± 2 .8mV ,88± 9vs 2 33± 37V/s,P均 <0 .0 1,伤后 2 4h有所恢复。②AP复极化时程 (APD)缩短 ,以APD50 和APD90 缩短明显 ,烧伤后 3h和 8h二者均显著缩短 ,8h尤为明显 ,而APD10 仅伤后 8h稍缩短 ,且APD10 、APD50 和APD90 于烧伤后 2 4h已基本恢复正常 ;③伤后 8h大鼠心肌细胞膜总ATPase、Mg2 + ATPase和Na+ K+ ATPase活性均显著下降。结论 :烧伤早期主要影响Na+ 、K+ 离子流 ,Na+ 、K+ 内流均被抑制 ,K+

To study action potentials of myocardiocytes and ATPase activity after early serious burn injury in rats.Conventional microelectrodes was used to record resting potentials(RP) and action potentials(AP) of ventricular papillary muscle of control group and the 1 h,3 h,8 h and 24 h after burn injured groups(35% TBSA Ⅲ°).ATPase activity was measured at 8h after burn injury.Results:①RP?APA and Vmax were all decreased significantly after early injury,and was all down to the lowest level at 8 h respectivelly -64±2 vs -87±2 mV,88.4±0.05 vs 123.1±2.8 mV,88±9 vs 233±37 V/s, P<0.01 ,then recovered gradually.②APD 50 and APD 90 were shortened at 3 h and 8 h,APD 10 shortened only at 8 h,and all recovered nearly to the control level at 24 h after injury.③Total ATPase?Mg 2+ ATPase and Na + K + ATPase activity were all reduced significantly at 8 h after injury.Conclusion:Serious burn injury accelerates K + efflux current but inhibits Na +?K + influx current.