Beta adrenergic receptor activity in peripheral vascular beds of the unanesthetized dog.

The effects of blockade and stimulation of beta adrenergic receptors on mesenteric, renal and hindlimb circulations have been investigated in unanesthetized resting dogs. Propranolol and isoproterenol have been used for beta blockade and stimulation, respectively. The changes in oxygen consumption in the hindlimb following beta receptor stimulation have also been studied in some experiments performed under anesthesia. Beta receptor blockade was followed by an increase in vascular resistance which was very slight in the kidney, quite marked in the mesenteric bed and still greater in the hindlimb. This effect was accompanied by moderate bradycardia and moderate arterial hypertension. Beta receptor stimulation caused, besides tachycardia and hypotension, a drop in vascular resistance in mesenteric and hindlimb circulations. In the latter, the effect was greater, it peaked considerably later and was paralleled by an increase in local oxygen consumption. The data suggest that beta adrenergi...