adrenergic receptor (redirected from Alpha adrenergic receptor)

adrenergic receptor

n.

Any of several reactive components of effector tissues most of which are innervated by adrenergic postganglionic fibers of the sympathetic nervous system and are activated by norepinephrine, epinephrine, and various adrenergic drugs. They are classified as alpha-adrenergic receptors and beta-adrenergic receptors according to their response to various adreneregic activating and blocking agents. Also called adrenoreceptor.

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Adrenergic receptor

There are three families of adrenergic receptors, alpha₁, alpha₂ and beta, and each family contains three distinct subtypes. Each of the nine subtypes are coded by separate genes, and display specific drug specificities and regulatory properties.

Mentioned in: Alpha 1 -Adrenergic Blockers

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adrenergic receptor

Etymology: L, ad + ren, kidney; Gk, ergon, work; L, recipere, to receive

a site in a sympathetic effector cell that reacts to adrenergic stimulation. Two types of adrenergic receptors are recognized: alpha-adrenergic, which act in response to sympathomimetic stimuli, and beta-adrenergic, which block sympathomimetic activity. In general, stimulation of alpha receptors is excitatory of the function of the host organ or tissue, and stimulation of the beta receptors is inhibitory.

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adrenergic receptor

Neurophysiology Any of a family of cell membrane receptors that receive neuronal impulses from postganglionic adrenergic fibers from the sympathetic nervous sytem, which are divided into α receptors, which results in an excitatory response of smooth muscle cells to catecholamines, and β receptors, which result in an inhibitory response to catecholamines; the GI tract is an exception, in that either α or β receptor stimulation results in relaxation