Effect of befol and sufan on neurogenic atrial fibrillation

Abstract

Antiarrhythmic activity of befol in neurogenic atrial fibrillation is due to its cardiotropic and cholinolytic effects and coincides with the dynamics of the tonic component of vagal chronotropic influence. Unlike befol, sufan has no effect on the duration of atrial fibrillation despite a reduction of synchronizing component of the vagal chronotropic influence. Tonic component remains unchanged, which is probably responsible for the absence of antiarrhythmic activity of sufan. The antidepressant befol (4-chlor-N-(3-morpholinopropyl)-benzamine hydrochloride, monoamine oxidase type A inhibitor, serotonin antagonist) [1,2,8,10] and the nonglycoside cardiotonic sufan (Nsuccine-dl-tryptophan dipotassium salt) [9] diminish cardiotoxic effects of bonnecor, propranolol, verapamil, and other antiarrhythmic drugs [15]. Befol and sufan also possess intrinsic antiarrhythmic activity in various models of cardiac rhythm disturbances (CRD) and potantiate the effect of antiarrhythmic drugs.For instance, befol has an antiarrhythmie effect in atrial arrhythmia induced by damage to the sinus node, early and delayed occlusion and reperfusion ventricular CRD induced by myocardial ischemia and elevates ventricular fibrillation threshold. Befol is superior to quinidine, ethmozine, and bonnecor in antiarrhythmic activity (in isotoxie doses) [3,15]. Antiarrhythmic effects of verapamil and bonnecor in delayed ventricular CRD can be potentiated by befol+ verapamil and by befol+bonnecor [15]. Befol elicits antiarrhythmic effect in central CRD induced by injection of aconitine, barium chloride or ouabaine Department of Pharmacology, Department of Normal Physiology, Kuban' State Medical Academy', Krasnodar into the fourth brain ventricle [ 15]. The antiarrhythmic activity of befol is associated with modulation of Na/Ca 2+ exchange in cardiomyocytes [13,16], antianginal properties [15], and activation of stresslimiting systems due to accumulation of serotonin in the central nervous system [14].Sufan can prevent and stop reperfusion-, strophanthin-, and barium chloride-induced arrhythmias. Its antiarrhythmic effect is comparable to that of lidocaine. Sufan potentiates antifibrillatory effect of lidocaine in reperfusion arrhythmia [4]. Antiarrhythmic activity of sufan is mediated through modulaton of Ca 2 § exchange in cardiomyocytes [5,6].The aim of the present study was to evaluate antifibrillatory activity of befol and sufan under conditions of neurogenic atrial fibrillation (NAF), the most adequate model of natural atrial CRD. MATERIALS AND METHODSExperiments were carded out on 16 cats weighing 2.5-4.5 kg. The animals were narcotized with Chloralose-Nembutal and artificially ventilated.The method was described in details elsewhere [7,12]. Befol (n--8) and sufan (n=8) were injected intravenously in doses of 20 and 40 mg/kg, respectively.