环维黄杨星D对大鼠心室乳头肌电生理作用

 目的 探讨环维黄杨星D(CVB-D)对大鼠离体右心室乳头肌的电生理作用。方法 采用标准玻璃微电极技术,观察记录大鼠离体右心室乳头肌跨膜电位。结果 CVB-D具有剂量依赖效应，在0.3?3.3μmol·L^-1,CVB-D对动作电位各参数无明显影响，但在13.3?63.3 μmol·L^-1呈剂量依赖性延长动作电位复极化时程，主要延长APD₅₀APD₇₀和APD₉₀;在33.3?63.3/μmiol?L¹呈剂量依赖性抑制静息电位(RP)、动作电位幅值(APA)和0期最大去极化速度(V_max)。研究结果还显示，CVB-D还具有时间依赖效应，当20μmio·L^-1灌流心室肌10 min后开始出现作用，随着药物作用时间的延长，APD₅₀APD₇₀和APD₉₀也逐渐增大，但是到30 min左右时作用达最高峰，而且至少可持续60 min。此外，CVB-D明显延长动作电位的有效不应期（ERP)、增大ERP 与心室肌细胞动作电位时程(APD)的比值。结论 CVB-D具有延长APD及ERP以及增大ERP与APD的比值的作用。

Electrophysiological effects of cyclovirobuxine D on the ventricular papillary muscle of rats

OBJECTIVE To explore the electrophysiological effects of cyclovirobuxine D (CVB-D) on the isolated right ventricular papillary muscle of rats. METHODS Transmembrane potentials were recorded with conventional glass microelectrodes. RESULTS CVB-D did not show significant influence on all parameters of action potential within the concentration range of 0.3?3.3μmol·L^-1，while CVB-D prolongated action potential duration in dose-dependent way within the concentration range of 13.3?63.3μmol·L^-1, mainly APD₅₀APD₇₀ and APD₉₀. Within the concentration range of 33.3?63.3/μmol·L^-1, CVB-D depressed rest potential (RP), action potential amplitude(APA) and the maximum rate of depolarization (V_max) in dose-dependent manner. Meanwhile, CVB-D prolongated APD₅₀APD₇₀ and APD₉₀ time-dependentiy at 20 μmol?L^-1，i.e., the primary action was attained at 10 min, and the strongest action reached at about 30 min. Thereafter, these parameters of action potential were hold at certain levels for at least 60 min. CONCLUSION CVB-D not only prolongated APD in dose-dependent and time-dependent manner, but also prolongated ERP and the ratio of ERP/APD, which denoted its antiarrhythmic action.