【摘要】 目的:观察低浓度的毒毛旋花子苷原（Strophanthidin,Str）对离体豚鼠心脏是否有强心作用,及其与心肌细胞膜Na⁺,K⁺-ATP酶活性的关系。方法:采用Langendorff离体灌流装置经主动脉逆行灌流心脏;八道生理记录仪记录心率（HR）,左室内压（LVP）及其最大变化速率(±dP/dt_max);无机磷法测定心肌细胞膜Na⁺,K⁺-ATP酶活性。结果:Str 0.1nmol/L可兴奋Na⁺,K⁺-ATP酶活性（P<0.05）但不影响心脏的收缩功能,Str 1nmol/L仅能升高+dP/dt_max（P<0.05）并兴奋Na⁺,K⁺-ATP酶活性（P<0.01）,Str 10和100 nmol/L可升高LVP和+dP/dt_max（P<0.05或P<0.01）,对Na⁺,K⁺-ATP酶活性无明显作用,Str 1-100μmol/L虽能短暂升高LVP和±dp/dt_max（P<0.01）,但随后出现不规则收缩并使LVP和±dP/dt_max降低,其对Na⁺,K⁺-ATP酶活性则表现为剂量依赖性抑制作用（P<0.01）。结论:高浓度Str的正性肌力作用是通过抑制Na⁺,K⁺-ATP酶活性实现的,而低浓度Str的强心作用似与Na⁺,K⁺-ATP酶抑制作用无关。更多还原

【Abstract】 AIM: To evaluate the effects of strophanthidin（Str） on cardiac contractile function and sarcolemmal Na⁺, K⁺-ATPase activities in isolated guinea-pig hearts. METHODS: Isolated guinea-pig hearts were perfused through aorta in a Langendorff mode. Heart rate（HR）, left ventricular pressure（LVP）, and first derivatives(±dp/dt_max) of LVP were recorded by eight-channel physiological instrument. Cardiac sarcolemmal Na⁺, K⁺-ATPase activities were determined with colorimetry. RESULTS: Str 0.1 nmol/L stimulated the Na⁺, K⁺-ATPase activities（P<0.05）, but had no effect on HR, LVP, and ±dp/dt_max. Str 1 nmol/L increased +dp/dt_max （P<0.05） and Na⁺, K⁺-ATPase activities（P<0.01）. Str 10 and 100 nmol/L significantly increased both LVP（P<0.05） and +dp/dt_max （P<0.05 or P<0.01）, and had no significant effects on Na⁺, K⁺-ATPase activities. However, Str 1-100μmol/L at first enhanced the LVP and ±dp/dt_max （P<0.01）, then reduced them resulting from irregular contraction, and effects of Str on Na⁺, K⁺-ATPase activities revealed a concentration-dependent inhibition（P<0.01）. CONCLUSION: The positive inotropic effects and irregular contraction produced by Str at higher concentrations result from the inhibition of Na⁺, K⁺-ATPase activities, and the positive inotropic effects of Str at lower concentrations are not related to the inhibition of the Na⁺, K⁺-ATPase activities.更多还原