alpha receptor


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Related to alpha receptor: beta receptor

alpha receptor

any of the postulated adrenergic components of receptor tissues that respond to norepinephrine and to various blocking agents. The activation of alpha receptors causes physiologic responses such as increased peripheral vascular resistance, pupil dilation, and contraction of arrector muscles. Also called alpha-adrenergic receptor. Compare beta receptor.

alpha receptor

A pair of G protein-coupled cell membrane receptors in the sympathetic nervous system, which evoke an excitatory response of smooth muscle cells to catecholamines.
Alpha1 (Gq) coupled receptors cause smooth muscle contraction, resulting in vasoconstriction in the skin, GI tract, kidney and brain, as well as causing smooth muscle contraction in the ureter, vas deferens, arrector pili (hair–“goosebumps”), pregnant uterus, and elsewhere. Alpha1 receptor activation is also linked to  glycogenolysis and gluconeogenesis in fat and liver, sweating, and sodium absorption in the kidneys.
Alpha2 (Gi) coupled receptors inhibit insulin secretion, trigger glucagon release (pancreas), contract GI sphincters, inhibit presynaptic release of noradrenaline in the CNS, and increase platelet aggregation.
References in periodicals archive ?
Antiviral activity of interferon is mediated by its binding to cell-specific interferon alpha receptors (IFNAR).
Previous studies confirmed that suppression of IFN alpha receptors can be appreciated among males with high HBV-DNA and HCV-RNA replication rate leading to suppression of cell mediated immunity, poor response to pegylated-IFN therapy and increase susceptibility of progression to hepatocellular carcinoma in co-infected patients.
When estrogen binds to an alpha receptor, it usually signals the cell to start copying itself.
This means that there's no, or very little, estrogen to tell the alpha receptor to make cells multiply.
The researchers then collected blood samples and determined the density of alpha receptors on platelets, which are essential for blood coagulation, and the density of beta receptors on lymphocytes, a type of white blood cell.
The findings indicate that as type A ranking increases, the ratio of of beta to alpha receptors increases, suggesting alpha receptors are preferentially stimulated in type A individuals, Kahn told SCIENCE NEWS.