Adrenaline; the effects in presence of beta blocker in isolated mammalian heart

ABSTRACT

There is no doubt that the effects of the catecholamines of the heart are mainly due to the stimulation of beta-adrenoceptors but in the mid 1960' s the first evidence was presented that a-adrenoceptors mediating positive inotrpoism exists also in the myocardium beside well established beta -adrenoceptors. In our observation adrenaline shows a positive inotropic response. The response of adrenaline in presence of metoprolol [beta1blocker] showed negative inotropic effect