This is an old revision of this page, as edited by 58.78.199.193 (talk) at 15:14, 12 November 2006 (→Structure and function). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 15:14, 12 November 2006 by 58.78.199.193 (talk) (→Structure and function)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)The GABAA receptor is one of the three ligand-gated ion channels responsible for mediating the effects of Gamma-AminoButyric Acid (GABA), the major inhibitory neurotransmitter in the brain.
Agonists and antagonists
Other ligands (besides GABA) interact with the GABAA receptor to activate it (agonists), to inhibit its activation (antagonists) or to increase or decrease its response to an agonist (positive and negative allosteric modulators). Such other ligands include benzodiazepines (increase pore opening frequency; often the ingredient of sleep pills and anxiety medications), imidazopyridines (newer class of sleep medications), barbiturates (increase pore opening duration; used as sedatives), and certain steroids, called neuroactive steroids.
Among antagonists are picrotoxin (which blocks the channel pore) and bicuculline (which occupies the GABA site and prevents GABA from activating the receptor). The antagonist flumazenil is used medically to reverse the effects of the benzodiazepines.
A useful property of the many agonists and some antagonists is that they often have a greater interaction with GABAA receptors which contain specific subunits. This allows one to determine which GABAA receptor subunit combinations are prevalent in particular brain areas and provides a clue as to which subunit combinations may be responsible for behavioral effects of drugs acting at GABAA receptors. Among the behavioral effects of such drugs are relief of anxiety (anxiolysis), muscle relaxation, sedation, anticonvulsion, and anesthesia.
See also
References
- Chen K., Lia H.Z., Yea N., Zhanga J., and Wang J.J. 2005. Role of GABAB receptors in GABA and baclofen-induced inhibition of adult rat cerebellar interpositus nucleus neurons in vitro. Brain Research Bulletin, 67(4), 310-318.
- Colquhoun D. and Sivilotti L.G. 2004. Function and structure in glycine receptors and some of their relatives. Trends in Neurosciences, 27(6), 337-344.
- Martin I.L., and Dunn S.M.J. 2002. "GABA Receptors". Tocris Cookson Ltd.
- Siegel G.J., Agranoff B.W., Fisher S.K., Albers R.W., and Uhler M.D. 1999. Basic Neurochemistry: Molecular, Cellular and Medical Aspects, Sixth Edition. GABA Receptor Physiology and Pharmacology. American Society for Neurochemistry. Lippincott Williams and Wilkins.
- Cossart R, Bernard C, Ben-Ari Y. 2005. Multiple facets of GABAergic neurons and synapses: multiple fates of GABA signalling in epilepsies. TRENDS in Neurosciences, 28(2), 108-115
External links
- Basic Neurochemistry: GABA Receptor Physiology and Pharmacology
- Dr. Dreyer's GABA-R webpage (University of Fribourg, Switzerland)