低浓度毒毛旋花子苷原对离体豚鼠衰竭心脏的影响

目的　研究低浓度毒毛旋花子苷原 (strophanthidin ,Str)对离体衰竭心脏心功能及心肌细胞膜Na+,K+ ATP酶活性的影响。方法　Langendorff离体心脏灌流装置制备戊巴比妥钠心衰模型 ,八道生理记录仪测定不同浓度Str对心功能的影响 ,无机磷法测定各组心肌细胞膜Na+,K+ ATP酶活性。结果　Str 1× 10 -9～ 1× 10 -7mol·L-1均能不同程度地持续增加衰竭心脏的心率、左室收缩压及左室收缩的最大速率 ,但 1× 10 -7mol·L-1对Na+,K+ ATP酶活性无明显抑制 ,1× 10 -10 ～ 1× 10 -8mol·L-1则可升高Na+,K+ ATP酶的活性 (P <0 0 5或P <0 0 1)。 1× 10 -6 ～ 1× 10 -4 mol·L-1可使心功能指标先升高、后降低 ,且伴有心脏收缩不规则和心律失常 ,也可剂量依赖性地抑制Na+,K+ ATP酶活性 (P <0 0 1)。结论　高浓度Str的正性肌力及伴有的心脏毒性作用是通过抑制Na+,K+ ATP酶实现的 ;而低浓度的正性肌力作用则和Na+,K+ ATP酶抑制无关

Effect of low concentrations of strophanthidin on isolated guinea pig failure hearts

AIM To study the effects of strophanthidin (Str) on cardiac function and Na +,K +-ATPase activity in isolated guinea pig heart failure model. METHODS Langendorff isolated heart failure models made by perfusing heart with K-H solution containing sodium pentobarbital. Eight-channel physiological recording instrument was used to determine cardiac function. Colorimetry method was used to determine cardiac sarcolemmal Na +,K +-ATPase activity. RESULTS Str increased the heart rate, left ventricular systolic pressure and the maximum rise or decline rate of left ventricular pressure in a concentration-dependent manner at 1×10 -9～1×10 -7 mol·L -1. But Str caused first a rise, then a reduction of contractility and arrhythmia accompanied by inhibition of Na +,K +-ATPase when the concentration of Str was higher than 1×10 -6 mol·L -1. Str had no obvious effect on Na +,K +-ATPase activity at 1×10 -7 mol·L -1, but increased cardiac activity at 1×10 -10～1×10 -8 mol·L -1. CONCLUSION The inotropic effect and heart toxicity of Str at higher concentration is due to inhibition of Na +,K +-ATPase, but the inotropic effect of Str at lower concentration is not the result of inhibition of Na +,K +-ATPase activity.