摘要
恒速静脉灌注中华眼镜蛇毒CTX,对在位大鼠心脏有选择性的毒性作用,表现为R波低电压,S-T段下移,T波平坦或倒置,束支传导阻滞,Q-T间期延长,继而出现室性早搏、室速,进而发展为室扑、室颤.预先静脉缓慢灌注15mg/kg CaCl_2,能提高大鼠产生室性心律失常所需的CTX量.预先静脉注射200或300mg/kg葡萄糖酸钙,对CTX中毒的小鼠亦有非常显著的保护作用.
Cardiotoxin in large constant dose has marked toxicity on in situ rat hearts.ECG alterations are first manifested by a great diminution in the R-wave voltage, and by a downward shift of the S-T segment.The J point may show a depression similar to that caused by myocardial ischemia.The normally upright T wave becomes diminished in amplitude, isoelectric or inverted in the II lead.The bundle branch conduction is blocked.The Q-T interval is prolonged.And ventricular premature impulses, ventricular tachycardia flutter and fibrillation occur subsequently.These effects occur somewhat later than the changes in the bundle branch conduction. when calcium chloride or calcium gluconate is given intravenously before CTX administration, the dose required to induce ventricular arrhythmia in the rats increased, and mice may be protected against the lethal dose of CTX.
