Ding B C, Gao Z Y, Wu M, Pi X J, Wang H Q
Department of Physiology, Hunan Medical University, Changsha.
J Tongji Med Univ. 1990;10(4):248-52. doi: 10.1007/BF02887940.
A comparison of the effects of magnesium valproate (MV) and sodium valproate (SV) on the action potential of isolated papillary muscle from guinea pigs and dogs was made in this study. The results in both animals were as follows: MV and SV induced a slight reduction of slope plateau of action potential and prolongation of action potential duration (APD). What is more, APD50 and APD90 were prolonged significantly, thus the ratio of APD90/APD25 was increased. The effective refractory period (ERP) was prolonged significantly. MV or SV showed no effects on action potential amplitude, overshoot, resting potential and phase 0 upstroke velocity. The above results suggested that MV and SV might play an antiarrhythmic role and that their effects were analogic. The mechanism of MV and SV inducing significant prolongation of APD50, APD90, and ERP, might be closely related to the slow-down of the velocity of K+ efflux during plateau and repolarization of phase 3 by radical of valproate and the slow-down of velocity of K+ efflux of repolarization of phase 3 in particular. These results showed that there was no difference in SV and MV action on guinea pigs and dogs.
本研究比较了丙戊酸镁（MV）和丙戊酸钠（SV）对豚鼠和犬离体乳头肌动作电位的影响。两种动物的实验结果如下：MV和SV均可使动作电位平台期斜率略有降低，动作电位时程（APD）延长。此外，APD50和APD90显著延长，因此APD90/APD25比值增大。有效不应期（ERP）显著延长。MV或SV对动作电位幅度、超射、静息电位及0期去极化速度均无影响。上述结果提示，MV和SV可能具有抗心律失常作用，且二者作用相似。MV和SV导致APD50、APD90及ERP显著延长的机制，可能与丙戊酸根使平台期及复极化3期K+外流速度减慢，尤其是复极化3期K+外流速度减慢密切相关。这些结果表明，SV和MV对豚鼠和犬的作用无差异。
