八厘麻毒素对兔心脏电生理参数的影响

目的 研究八厘麻毒素(Rh)对在体和离体兔心脏电生理参数的影响。方法 使用在体兔心脏模型和Langendo rf f 离体兔心脏灌流模型,观察并记录分别用Rh 12.5μg·kg^-1 和25μg·kg^-1(iv)或用含Rh 浓度为0.34 μmol·L^-1和0.68μmol·L^-1的K-H灌注液灌注兔心脏时,对在体或离体兔心脏电生理参数的影响。结果在Rh 12.5μg·kg^-1(iv)后20、40、60和80 min,心室舒张阈值(VDT),有效不应期(ERP)和相对不应期(RRP)均无显著变化;而Rh 25μg·kg^-1(iv)在用药后的同样时间内可见ERP 和RRP 显著延长(P<0.05)。另用含Rh浓度为0.34μmol·L^-1的K-H 灌注液行Lange ndorf f 灌注,心房相对不应期(A RRP)和心房有效不应期(AERP)显著延长(P<0.05~0.01);转用含Rh浓度为0.68μmol·L^-1的K-H灌注液行Langendorff 灌注,心房舒张阈值(ADT)、VDT 均明显升高(P<0.05 ~0.01),且ARRP,AERP,心室相对不应期(VRRP)和心室有效不应期(VERP)均显著延长(P<0.05 ~0.01)。结论 Rh能直接作用于心肌,升高心房、心室舒张期阈值和延长心房、心室不应期。

Effects of rhomotoxin on electrophysiologic parameters in rabbit heart

Aim To study effect s of rhomotoxin (Rh)on electrophysiologic parameters in rabbit heart.Methods The rabbi t heart s in vivo were injected with Rh 12.5μg·kg^-1,25μg·kg^{- 1} or saline iv respectively and the isolated rabbit hearts were perfused by Krebs-Henseleit(K-H)perfusion liquid containing Rh 0.34 μmol·L^-1 or 0.68μmol·L^-1.The electrophysiologic parameters were observed before and after drug adminitration.Results At 20, 40, 60 and 80 min after inject ion of Rh 12.5μg·kg^-1 iv, the VDT,ERP and RRP had no significant changes ;but at 20, 40, 60 and 80 min after inject ion of Rh 25 μg ·kg^-1 iv a significant prolongation of ERP and (or)RRP was found (P<0.05).Perfusion gisolated heart with Rh 0.34 μmol·L^-1 prolonged ARRP and A ERP (P<0.05, P<0.01);while perfusion gisolated heart with Rh 0.68 μmol·L^-1 increased ADT and VDT(P<0.05, P<0.01)and pro longed ARRP, AERP,VRRP and VERP (P<0.05, P<0.01).Conclusion Rh might have an effect of increasing atrial and ventricular diastolic threshold, which prolongates atrial and ventricular refractory period by direct action on rabbits myocardial muscle.