Relationship between hemodynamic changes and endogenous catecholamine release caused by a new antiarrhythmic agent, AB-2, in cats and dogs.

An antiarrhythmic agent, AB-2, given iv produced in cats and dogs a biphasic action on blood pressure: rapid and short-lasting hypertension followed by depression of blood pressure. The first phase was accompanied by a sharp rise of serum catecholamines (6-fold increase in adrenaline, and 4.5-fold increase in noradrenaline level) and of indices of left ventricular contractility. These effects were more pronounced in cats than in dogs. In cats, but not dogs, the biphasic effect was observed also after po administration. The elevated endogenous catecholamine release was not accompanied by an increase in plasma 11-hydroxycorticosteroids levels.