norepinephrine

l-(−)-α-(aminomethyl)-3,4-dihydroxybenzyl alcohol; a catecholamine hormone of which the natural form is d, although the l form has some activity; the base is considered to be the postganglionic adrenergic mediator, acting on α and β receptors; it is stored in chromaffin granules in the adrenal medulla, in much smaller amounts than epinephrine, and secreted in response to hypotension and physical stress; in contrast to epinephrine it has little effect on bronchial smooth muscle, metabolic processes, and cardiac output, but has strong vasoconstrictive effects and is used pharmacologically as a vasopressor, primarily as the bitartrate salt. SYN: levarterenol, noradrenaline.

- n. bitartrate (-)-α-(aminomethyl)-3,4-dihydroxybenzyl alcohol tartrate. For actions and uses, see n.. SYN: levarterenol bitartrate, noradrenaline acid tartrate, noradrenaline bitartrate.

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nor·epi·neph·rine .nȯr-.ep-ə-'nef-rən, -rēn n a catecholamine C₈H₁₁NO₃ that is the chemical means of transmission across synapses in postganglionic neurons of the sympathetic nervous system and in some parts of the central nervous system, is a vasopressor hormone of the adrenal medulla, and is a precursor of epinephrine in its major biosynthetic pathway called also arterenol, noradrenaline see LEVOPHED

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n.

see noradrenaline

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nor·epi·neph·rine (nor″ep-ĭ-nefґrin) 1. one of the naturally occurring catecholamines, a neurohormone released by the postganglionic adrenergic nerves and some brain neurons; it is a major neurotransmitter that acts on α- and β₁-adrenergic receptors. It is also secreted by the adrenal medulla in response to splanchnic stimulation and is stored in the chromaffin granules. It is a powerful vasopressor and is released in the body usually in response to hypotension or stress. Called also noradrenaline. 2. a pharmaceutical preparation of the same substance, usually used in the form of the bitartrate salt.