alpha 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.

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