血小板活化因子在缺血再灌注损伤中电生理作用的实验研究

Machanism of platelet activating factor on electrophysiological characteristics

目的 研究正常灌注、模拟缺血 /再灌注下血小板活化因子的电生理作用 ,初步探讨血小板活化因子的作用机制。方法 通过标准微电极技术 ,分析豚鼠左心室乳头肌在正常灌注、缺血 /再灌注时的血小板活化因子的电生理作用以及CV 6 2 0 9和格列本脲对其作用的影响。结果 血小板活化因子明显缩短了动作电位时相 ,灌注前后APD90 (90 %复极水平的动作电位时相 )分别为 (14 4 0± 5 8)ms和 (12 0 3±5 8)ms (n =8,P <0 0 0 1) ,CV 6 2 0 9(血小板活化因子受体阻断剂 )和格列本脲 (ATP敏感性K+ 通道阻断剂 )明显抑制了血小板活化因子诱发的动作电位持续时间缩短。CV 6 2 0 9组 (n =5 )、格列本脲组 (n =6 )和对照组相比较 ,血小板活化因子诱发的APD90 缩短率分别为 (5 8± 1 9) % ,(1 1± 1 9) %比 (16 4±1 8) % (P <0 0 5 ,P <0 0 0 1)。血小板活化因子引起了早期的动作电位持续时间的进一步缩短 ,相反 ,血小板活化因子引起再灌注早期的动作电位时相延长。结论 血小板活化因子明显缩短了动作电位时相 ,CV 6 2 0 9和格列本脲阻断血小板活化因子诱发的动作电位持续时间缩短 ,提示血小板活化因子受体和ATP敏感性K+ 通道 ,可能介入血小板活化因子电生理作用 ;血小板活化因子放大缺血 /再灌注时缺血区和?

Objective To investigate the effects and mechanism of platelet activating factor(PAF) on electrophysiological characteristics of papillary musckes in the different states.Methods Standard microelectrode technique was used to record and analyse transmembrane activity in guinea pig papillary muscles during normal perfusion,simulated ischemia reperfusion and under the influences of drugs in PAF induced electrophysiological effects.Results The action potential duration at 90% level of repolarization(APD 90 )was significantly shortened by PAF, P <0 001.CV 6209(PAF specific receptor blocker)and Glibenclamide(ATP sensitive K + channels blocker)inhibited the shortening of APD 90 induced by PAF.The shortening rate of APD 90 was(5 8±1 9)% and(1 1±1 9)% in CV 6209 group and Glibenclamide group,respectively.PAF induced a further shortening of action potential duration(APD) during early ischemia,but the effect of PAF was not shown during later ischemia.In contrast,PAF induced the lengthening of APD during early reperfusion.Conclusion PAF shorten the action potential duration.The shortening of the action potential duration is blocked by Glibenclamide and CV 6209.The results indicate that PAF specific receptor and ATP-sensitive K + channels might be involved in the effect of PAF.PAF amplifies heterogeneity between ischemic and normal zones during early ischemia reperfusion,which might play a vital role in ischemia reperfusion induced arrhythmias. [