Beta Adrenergic and Antiarrhythmic Effect of Apamin, A Component of Bee Venom

摘要

Apamin, a polypeptide, is one of three active components of bee venom having a molecular weight of 3,700. Its effects were studied in a series of 30 isolated perfused Langendorff heart preparations, and in 12 intact animals. When injected into the coronary circulation of the perfused heart, apamin produces a 50 plus or minus 10% increase in rate, a 150 plus or minus 50% increase in force of contraction and no change in coronary vascular resistance. These effects lasted for the duration of the experiment. In those hearts in which intrinsic arrhythmias are present a dose of 0.2 mg of apamin produced an immediate restoration of normal cardiac rhythm in addition to the effects on rate and force. In the intact monkey preparation this same dose of apamin produces an increase in heart rate, aortic blood flow and right ventricular force. There are no significant changes in arterial blood pressure, central venous pressure or cortical activity. In addition apamin appears to be nontoxic (LD50 = 15 mg/kg) when compared to whole bee venom (LD50 = 3.5 mg/kg). (Author)