Норэпинефрин

Химические свойства

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Использование

Norepinephrine is used for increasing cardiac constriction and for the necessary elevation of blood pressure after sharp decline, which can result from surgical intervention or trauma.

Определение

ChEBI: The R-enantiomer of noradrenaline.

Всемирная организация здравоохранения(ВОЗ)

Vasoconstrictor agents have been in use for many years to prolong duration of action of local anaesthetics, particularly in dentistry. Combination products containing epinephrine or levarterenol in concentrations of 1:80,000 or less remain widely available. See also WHO comment for epinephrine.

Биологические функции

Most central noradrenergic neurons are located in the nucleus locus ceruleus of the pons and in neurons of the reticular formation. Fibers from these nuclei innervate a large number of cortical, subcortical, and spinomedullary fields. Many functions have been ascribed to the central noradrenergic neurons, including a role in affective disorders (see Chapter 33), in learning and memory, and in sleep–wake cycle regulation.The mammalian CNS contains both α- and β-adrenoceptors.

Общее описание

Norepinephrine (NE, Levophed) differs from DA onlyby addition of a 1-OH substituent (β-OH-DA) and from Eonly by lacking the N-methyl group. Like DA, it is polar andrapidly metabolized by both COMT and MAO, resulting inpoor oral bioavailability and short DOA (1 or 2 minutes evenwhen given intravenously). It is a stimulant of α1-, α2-, andβ1-adrenoceptors (notice that lacking the N-methyl group resultsin lacking β2- and β3-activity). It is used to counteractvarious hypotensive crises, because its α-activity raisesblood pressure and as an adjunct treatment in cardiac arrestbecause its β-activity stimulates the heart. It has limitedclinical application caused by the nonselective nature of itsactivities.

Опасность

May cause local tissue necrosis, headache, bradycardia, hypertension; poison; teratogen; mutagen.

Фармаколо?гия

Norepinephrine is the primary neurotransmitter produced and released by adrenergic neurons, and in literature it is also described as and called () noradrenaline or levarterenol. This vasopressor catecholamine reduces both the resistance and capacity of blood vessels by stimulating α-adrenoreceptors and having a direct cardiostimulatory effect, which is accomplished by activation of β1-adrenoreceptors. Norepinephrine exhibits significantly less activity than epinephrine as a drug for widening blood vessels through the activation of β2-adrenoreceptors. Elevation of both stylistic and diastolic blood pressure is a typical reaction to intravenous introduction of norepinephrine.

Профиль безопасности

Poison by ingestion, intraperitoneal, subcutaneous, and intravenous routes. An experimental teratogen. Experimental reproductive effects. Human mutation data reported. A sympathomimetic vasopressor. When heated to decomposition it emits toxic fumes of NOx.

Методы очистки

Recrystallise adrenor from EtOH and store it in the dark under N2. [pKa, Lewis Brit J Pharmacol Chemother 9 488 1954, UV: Bergstr.m et al. Acta Physiol Scand 20 101 1950, Fluorescence: Bowman et al. Science NY 122 32 1955, Tullar J Am Chem Soc 70 2067 1948.] The L-tartrate salt monohydrate has m 102-104.5o, [] D -11o (c 1.6, H2O), after recrystallisation from H2O or EtOH. [Beilstein 13 III 2382.]