Functions
A variety of specific physiological functions have been attributed to the sigma-1 receptor. Chief among these are modulation of Ca2+ release, modulation of cardiac myocyte contractility, and inhibition of voltage gated K+ channels. The reasons for these effects are not well understood, even though sigma-1 receptors have been linked circumstantially to a wide variety of signal transduction pathways. Links between sigma-1 receptors and G-proteins have been suggested such as sigma-1 receptor antagonists showing GTP-sensitive high affinity binding, there is also, however, some evidence against a G-protein coupled hypothesis. The sigma-1 receptor has been shown to appear in a complex with voltage gated K+ channels (Kv1.4 and Kv1.5), leading to the idea that sigma-1 receptors are auxiliary subunits. Sigma-1 receptors apparently co-localize with IP3 receptors on the endoplasmic reticulum. Also, sigma-1 receptors have been shown to appear in galactoceramide enriched domains at the endoplasmic reticulum of mature oligodendrocytes. The wide scope and effect of ligand binding on sigma-1 receptors has led some to believe that sigma-1 receptors are intracellular signal transduction amplifiers.
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Famous quotes containing the word functions:
“In today’s world parents find themselves at the mercy of a society which imposes pressures and priorities that allow neither time nor place for meaningful activities and relations between children and adults, which downgrade the role of parents and the functions of parenthood, and which prevent the parent from doing things he wants to do as a guide, friend, and companion to his children.”
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