| a site on a cell, as of the heart, that, upon interaction with epinephrine or norepinephrine, controls heartbeat and heart contractability, vasodilation, smooth muscle inhibition, and other physiological processes. |
beta-adrenergic receptor n.
Any of various cell membrane receptors that can bind with epinephrine and related substances that activate or block the actions of cells containing such receptors. These cells initiate physiological responses such as increasing the rate and force of contraction of the heart as well as relaxing bronchial and vascular smooth muscle. Also called beta-receptor.