Dopamine

An important neurotransmitter (messenger) in the brain. Dopamine is classified as a catecholamine (a class of molecules that serve as neurotransmitters and hormones). It is a monoamine (a compound containing nitrogen formed from ammonia by replacement of one or more of the hydrogen atoms by hydrocarbon radicals). Dopamine is a precursor (forerunner) of adrenaline and a closely related molecule, noradrenaline. Dopamine is formed by the decarboxylation (removal of a carboxyl group) from dopa. Dopa is used in the treatment of Parkinson disease. Parkinson disease is believed to be related to low levels of dopamine in certain parts of the brain. When dopa is taken by mouth, it crosses through the blood-brain barrier. Once it has crossed from the bloodstream into the brain, it is converted to dopamine. The resulting increase in dopamine concentrations in the brain is thought to improve nerve conduction and to assist in lessening the movement disorders in Parkinson disease. In 1970 the FDA (Food and Drug Administration) approved dopa in the form of L-Dopa, or levodopa, for use in the US. The drug revolutionized the treatment of Parkinson disease.
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An intermediate in tyrosine metabolism and precursor of norepinephrine and epinephrine; it accounts for 90% of the catecholamines; its presence in the central nervous system and localization in the basal ganglia (caudate and lentiform nuclei) suggest that d. may have other functions. Depletion of d. produces Parkinson disease. SYN: 3-hydroxytyramine, decarboxylated dopa.
- d. hydrochloride a biogenic amine and neural transmitter substance, used as a vasopressor agent for treatment of shock.
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dihydroxyphenylethylamine

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do·pa·mine 'dō-pə-.mēn n a monoamine C8H11NO2 that is a decarboxylated form of dopa and occurs esp. as a neurotransmitter in the brain and as an intermediate in the biosynthesis of epinephrine see INTROPIN

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n.
a catecholamines derived from dopa that functions as a neurotransmitter, acting on specific dopamine receptors and also on adrenergic receptors throughout the body, especially in the limbic system and extrapyramidal system of the brain and in the arteries and the heart. It also stimulates the release of noradrenaline from nerve endings. The effects vary with the concentration. Dopamine is used as a drug to increase the strength of contraction of the heart in heart failure, shock, severe trauma, and septicaemia. It is administered by injection in carefully controlled dosage. Possible side-effects include unduly rapid or irregular heartbeat, nausea, vomiting, breathlessness, angina pectoris, and kidney damage.
Certain drugs (dopamine receptor agonists) have an effect on the body similar to that of dopamine. They include apomorphine, bromocriptine, pergolide, ropinirole, and cabergoline (Cabaser) and are used to treat parkinsonism. Drugs that compete with dopamine to occupy and block the dopamine receptor sites in the body are known as dopamine receptor antagonists. They include some antipsychotic drugs (e.g. the phenothiazines and butyrophenone) and certain drugs (e.g. domperidone and metoclopramide) used to treat nausea and vomiting.

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do·pa·mine (doґpə-mēn) 3,4-dihydroxyphenylethylamine, a catecholamine formed in the body by the decarboxylation of dopa; it is an intermediate product in the synthesis of norepinephrine, and acts as a neurotransmitter in the central nervous system. It is also produced peripherally and acts on peripheral receptors, e.g., in blood vessels. Called also 3-hydroxytyramine.

Medical dictionary. 2011.

Look at other dictionaries:

  • Dopamine — Molécule de dopamine Général …   Wikipédia en Français

  • Dopamine —    Dopamine is a neurotransmitter belonging chemically to the class of catecholamines.    The efficacy of many antipsychotic drugs is thought to reside in their success in blocking the receptors for dopamine in the brain, especially the D2… …   Historical dictionary of Psychiatry

  • dopamine — [ dɔpamin ] n. f. • 1949; de dopa et amine ♦ Physiol. Amine précurseur de la noradrénaline, indispensable à l activité normale du cerveau. ● dopamine nom féminin Neurotransmetteur du groupe des catécholamines, précurseur de la noradrénaline,… …   Encyclopédie Universelle

  • dopamine — dopamine. См. дофамин. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • dopamine — 1959, from DOPA, the amino acid (from first letter of elements of dioxyphenylalanine), + AMINE (Cf. amine) …   Etymology dictionary

  • dopamine — ☆ dopamine [dō′pə mēn΄, dō′əmin ] n. [d(ihydr)o(xy)p(henyl) + AMINE] an amine, C8H11NO2, that is an intermediate biochemical product in the synthesis of norepinephrine, epinephrine, and melanin, and is a neurotransmitter …   English World dictionary

  • Dopamine — For other uses, see Dopamine (disambiguation). Dopamine …   Wikipedia

  • dopamine — n. a catecholamine derived from dopa that functions as a neurotransmitter, acting on specific dopamine receptors and also on adrenoceptors throughout the body, especially in the limbic system and extrapyramidal system of the brain as well as the… …   The new mediacal dictionary

  • dopamine — /doh peuh meen /, n. 1. Biochem. a catecholamine neurotransmitter in the central nervous system, retina, and sympathetic ganglia, acting within the brain to help regulate movement and emotion: its depletion may cause Parkinson s disease. Cf. dopa …   Universalium

  • dopamine — (n.f.) Substance de l organisme qui agit sur celui ci comme un véritable booster, lui fournissant adrénaline et nonadrénaline en quantité suffisante pour maintenir un état euphorique chez l individu. La dopamine est en général sécrétée… …   Dictionnaire de Sexologie

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