眼镜蛇毒心脏毒素对心肌电及机械活动的影响(一)

EFFECT OF CARDIOTOXIN FROM THE VENOM OF NAJA NAJA ATRA ON THE ELECTRICAL AND MECHANICAL ACTIVITIES OF THE MYOCARDIUM

中华眼镜蛇毒心脏毒素(Cardiotoxin,简称CTX)对离体的豚鼠心肌电及机械活动有明显而持久的影响。1mg/L CTX可提高离体的大鼠心房和离体的豚鼠心脏肌张力,减少收缩振幅,ECG的S-T段下降或抬高,T波由正常倒置型全部转为直立,电压增加。离体的大鼠心房ERP、豚鼠心脏P-R及Q-T间期、心率、冠脉流量(CF)不变。反复用生理溶液冲洗标本,不能使CTX抑制了的标本恢复正常。而5mM Ca^(+2)拮抗CTX对心肌电及机械活动的影响。

Cardiotoxin(CTX)was separated from the venom of.Naja naja atra.CTX was shown to have prominent and consistent effects on the electrical and mechanical activities in the isolated rat auricles and isolated perfused guinea pig hearts.(1)CTX lug.ml^(-1)increased the tension of the myocardium and decreased the heart muscle contraction.(2)CTX increased the T-wave and depressed or/and elevated the S-T segment.(3)CTX had no effect on the effective refractory period in the rat left atria preparation and also had no effect on the P-R interval,Q-T interval,heart rate and coronary flow in the guinea pig hearts.(4)The actions of CTX seemed to be irreversible even after repeated washing with physiological saline,but it could be antagonisted by an excess of calcium ions(5mM). The results suggested that the effects of CTX may not be related to the blockade of Na-K-ATPase.