epinephrine ep·i·neph·rine or ep·i·neph·rin (ěp'ə-něf'rĭn)
A catecholamine hormone of the adrenal medulla that is the most potent stimulant of the sympathetic nervous system, resulting in increased heart rate and force of contraction, vasoconstriction or vasodilation, relaxation of bronchiolar and intestinal smooth muscle, glycogenolysis, lipolysis, and other metabolic effects. Also called adrenaline.
A white to brownish crystalline compound isolated from the adrenal glands of certain mammals or synthesized and used in medicine as a heart stimulant, vasoconstrictor, and bronchial relaxant.
A hormone that is secreted by the adrenal gland in response to physical or mental stress, as from fear, and is regulated by the autonomic nervous system. The release of epinephrine causes an increase in heart rate, blood pressure, and respiratory rate. Epinephrine also raises glucose levels in the blood for use as fuel when more alertness or greater physical effort is needed. Also called adrenaline. Chemical formula: C9H13NO3.