epinephrine

Pronunciation: ep′i-nef′rin

Definition: A catecholamine that is the chief neurohormone of the adrenal medulla of most species; also secreted by certain neurons. The l-isomer is the most potent stimulant (sympathomimetic) of adrenergic α- and β-receptors, 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; used in the treatment of bronchial asthma, acute allergic disorders, open-angle glaucoma, cardiac arrest, and heart block, and as a topical and local vasoconstrictor. Generally used salts are epinephrine hydrochloride and epinephrine bitartrate, the latter most frequently used in topical preparations.

Synonym(s): adrenaline

[epi- + G. nephros, kidney, + -ine]

See Also: emergency theory, fight or flight response

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