Effect of Acebutolol on Plasma Catecholamine Concentrations in Anesthetized Dogs with Ouabain-Induced Arrhythmias and its Direct Actions in Vitro on the Adrenal Medulla

抄録

We have performed studies on blood hormone dynamics following intravenous administration of acebutolol, a newly synthesized, β-blocker, and its direct action on the adrenal medulla in vitro.
Intravenous injection of acebutolol into anesthetized dogs almost doubled the plasma adrenaline and noradrenaline concentrations within 5 to 15 minutes, while renin activity was reduced to approximately two-thirds of the pre-administration level.
When arrhythmia was induced in dogs with ouabain, the plasma adrenaline and noradrenaline levels increased to 220±109 and 392±84pg/ml, respectively, from the basal levels of 44±24 and 140±43pg/ml. The restoration of sinus rhythm following the administration of acebutolol was accompanied by a further increase in the plasma adrenaline and noradrenaline levels to 797±364 and 1226±263 pg/ml, respectively. A perifusion experiment indicated that acebutolol directly accelerated catecholamine release from the adrenal medulla in pigs.