GABAC receptor

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The correct title of this article is GABA_C receptor. It features superscript or subscript characters that are substituted or omitted because of technical limitations.

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The GABA_C receptor is a biochemical receptor for the neurotransmitter Gamma-aminobutyric acid (GABA). It is linked to chloride channels, with distinct physiological and pharmacological properties. In contrast to the fast and transient responses elicited from GABA_A receptors, GABA_C receptors mediate slow and sustained responses. GABA is about 10 times more potent at GABA_C receptors than it is at most GABA_A receptors.^[1]

GABA_C receptors exist in retina cells.^[2]

[edit] Pharmacology

There are several pharmacological differences between GABA_C receptors and the other type of ligand-gated GABA receptor, the GABA_A receptors (GABA_B receptors are metabotropic receptors). GABA_C receptors are not sensitive to the GABA_A receptor antagonist bicuculline and the GABA_B agonist baclofen. Also, they are not modulated by many GABA_A receptor modulators (such as benzodiazepines and barbiturates and neuroactive steroids). GABA_C receptors open their channels in response to binding of cis-aminocrotonic acid, a slight variation of the GABA molecule that does not activate either the GABA_A or GABA_B receptors.^[1] GABA_C receptors, like GABA_A receptors, are blocked by picrotoxin.^[1] Like other ligand-gated ion channels, the molecule is probably formed by five subunits arranged around a central pore. Like the GABA_A channel, the pore, when open, is permeable to chloride ions, though its conductance is smaller than that of GABA_A.

[edit] Genetics

In humans, GABA_C receptors are encoded by genes which are found on chromosome 6.^[1] The genes that code for the subunits of the GABA_A receptors are on chromosomes 4, 5, 15, and the X chromosome.^[1]

[edit] Reference

^ ^a ^b ^c ^d ^e Martin IL and Dunn SMJ. GABA receptors A review of GABA and the receptors to which it binds. Tocris Cookson LTD. Accessed through web archive on February 14, 2007.
^ Qian H. 2000. GABAc receptors in the vertebrate retina. Retrieved on February 14, 2007.