碘杂环化合物对离体豚鼠心乳头肌动作电位和收缩力的作用

The Effects of Iodium-Heterocyclic Compound on the Action Potentials and Contractile Force of Isolated Guinea Pig Papillary Muscles

采用细胞内微电极记录技术,同步观察了3,6-[二甲氨基]-二苯并碘因甲酸盐(IHC-64)对豚鼠心乳头肌细胞动作电位和收缩力的作用。50μmol/L IHC-64抑制心肌收缩力,而不影响快反应动作电位。增加IHC-64浓度,动作电位0相最大峰值(APA)、除极速率(dp/dt_(max))和复极50％和90％时程(APD_(50)、APD_(90))被明显抑制。IHC-64抑制慢反应动作电位,提高细胞外钙浓度可拮抗这种抑制。结果提示,IHC-64主要抑制慢Ca^(2+)内流,同时也部分抑制快Na^+内流,它可能是一种新型B类钙通道阻滞剂。

The effects of iodium-heterocyclic compound (3,6-di-dimethylamino -di-benzopyriodonium formate, IHC-64) on the action potentials and contractile force of isolated guinea pig papillary muscles were investigated in this paper. 50μm IHC-64 only inhibited contractile force and had not any effect on APA, dp/dtmax, APD50, APD90 of fast action potentials in normal Tyrode,s solution. All of these parametres were depressed with further increased concentration of IHC-64. In K+ -rich Tyrode,s solution, the depression of IHC-64 on slow action potentials and contractile fo-ce could be antagonized by extracellular calcium. These results suggest that IHC-64 inhibit not only slow calcium influx but also fast sodium influx, and it may be a new calcium channel blocker.