This study is to investigate the effects of
phenytoin sodium,
lidocaine (
sodium channel blockers),
propranolol (
beta-adrenergic receptor antagonist),
amiodarone (drugs prolonging the action potential duration) and
verapamil (
calcium channel blockers) on
arrhythmia of mice induced by Bufonis Venenum (
Chansu) and isolated mouse hearts lethal dose of
Chansu.
Arrhythmia of mice were induced by
Chansu and then electrocardiograms (ECGs) were recorded. The changes of P-R interval, QRS complex, Q-T interval, T wave amplitude, heart rate (HR) were observed. Moreover,
arrhythmia rate, survival rate and
arrhythmia score were counted. Isolated mouse hearts were prefused, and the lethal dose of
Chansu was recorded. Compared with control group, after pretreatment with
phenytoin sodium, broadening of QRS complex and HR were inhibited, and the incidence of ventricular
arrhythmia was reduced dramatically, while survival rate was improved; the isolated mouse hearts lethal dose of
Chansu was increased significantly. After pretreatment with
lidocaine, the prolongation of P-R interval and broadening of QRS complex were inhibited, and the incidences of ventricular
arrhythmia were reduced dramatically, while survival rate was improved; the isolated mouse hearts lethal dose of
Chansu was increased significantly. After pretreatment with
propranolol, prolongation of P-R interval, broadening of QRS complex, prolongation of Q-T interval and HR were inhibited, and the incidences of both supraventricular and ventricular arrhythmias were reduced dramatically, while survival rate was improved. After pretreatment with
amiodarone, HR was inhibited, the incidences of
ventricular tachycardia were reduced dramatically. Lastly, after pretreatment with
verapamil, the prolongation of P-R interval and Q-T interval were inhibited and the incidences of both supraventricular and ventricular arrhythmias were reduced dramatically; the isolated mouse hearts lethal dose of
Chansu was reduced significantly. In in vivo experiments,
phenytoin sodium was most effective against the mice arrhythmias induced by
Chansu while cautious use of
verapamil for
Chansu inducing
arrhythmia should be noted. It is also concluded that mice ventricular arrhythmias induced by
Chansu might be most closely related to
sodium channel, supraventricular arrhythmias might be related to
beta-adrenergic receptor, and
calcium channel plays an important role in conduction block. In in vitro experiments,
phenytoin sodium was most effective, followed by
lidocaine and
propranolol, and
amiodarone had no obvious effect and
verapamil reduced the lethal dose of
Chansu.