2-[对-(二甲氨基)苯乙烯]氯化甲基吡啶对大鼠心电图、豚鼠左心房收缩及乳头肌动作电位的影响

2-对-(二甲氨基)苯乙烯]氯化甲基吡啶(DSPM-Cl),是由氯取代2-对-(二甲氨基)苯乙烯]碘化甲基吡啶(DSPM)上的碘而得。本文应用心电图、机械收缩描记方法及细胞内标准微电极技术,研究DSPM-Cl对大鼠心电图(ECG)、豚鼠心房肌量效曲线及对豚鼠乳头肌快反应动作电位(AP)、高钾除极慢反应动作电位(SAP)的影响。结果显示,DSPM-Cl(2mg·kg^-1)对大鼠有明显的负性频率、负性传导作用,分别使PP间期、PR间期延长达66.2%(P<0.01),17.0%(P<0.01),50μmol·L^-1能明显抑制左心房收缩力,非竟争性拮抗Iso及CaCl₂对豚鼠左心房的正性肌力作用,PD^2'分别为4.6,4.34,100μmol·L^-1DSPM-Cl延长动作电位时程APD₉₀,有效不应期(ERP),降低高钾除极豚鼠乳头肌0期最大上升速率Vmax,其作用与Ver相似,提示DSPM-Cl可能为钙拮抗剂。

EFFECTS OF 2-(P-DIMETHYLAMINOSTYRYL)PYRIDINE METHYCHOLIDE(DSPM-Cl)ON ECG,LEFT ATRIUM CONTRACTIVITY AND ON PAPILLARY MUSCLE ACTION POTENTIALS

The effects of DSPM-Cl on ECG in rats, on the dose effect curve in guinea pigleft atria and on the fast action potential(AP),high-K⁺depolarized slow action potential(SAP)inguinea pigs papillary muscle were examined electrophysiologically.DSPM-Cl(2 mg·kg^-1showedsignifieant nagative frequency, negative conductivity effect, and prolonged the PP and PR interval. DSPM-Cl(30～50μmol·L(-1)was shown to inhibit left atria contractility and shift the concentra-tion-response curve of Iso and CaCl₂ to the right with PD^2'values of 4.60and 4.13, respectively.Inaddition, DSPM-Cl was found to prolong the duration of action potential 90(APD₉₀)and effectiverefractory peried(ERP),and decrease the maximal upstroke velocity(Vmax)in K⁺-depolarizedguinea pigs papillary muscles.The results suggest that,like verpamil,DSPM-Cl might be a calciumantagonist.