title: Extrasynaptic GABAA receptors: form, pharmacology, and function.
abstract: GABA is the principal inhibitory neurotransmitter in the CNS and acts via GABA(A) and GABA(B) receptors. Recently, a novel form of GABA(A) receptor-mediated inhibition, termed "tonic" inhibition, has been described. Whereas synaptic GABA(A) receptors underlie classical "phasic" GABA(A) receptor-mediated inhibition (inhibitory postsynaptic currents), tonic GABA(A) receptor-mediated inhibition results from the activation of extrasynaptic receptors by low concentrations of ambient GABA. Extrasynaptic GABA(A) receptors are composed of receptor subunits that convey biophysical properties ideally suited to the generation of persistent inhibition and are pharmacologically and functionally distinct from their synaptic counterparts. This mini-symposium review highlights ongoing work examining the properties of recombinant and native extrasynaptic GABA(A) receptors and their preferential targeting by endogenous and clinically relevant agents. In addition, it emphasizes the important role of extrasynaptic GABA(A) receptors in GABAergic inhibition throughout the CNS and identifies them as a major player in both physiological and pathophysiological processes.
authors.affiliation: Division of Medical Sciences, Centre for Neuroscience, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, United Kingdom.
authors.forename: Delia
authors.initials: D
authors.lastname: Belelli
authors.forename: Neil L
authors.initials: NL
authors.lastname: Harrison
authors.forename: Jamie
authors.initials: J
authors.lastname: Maguire
authors.forename: Robert L
authors.initials: RL
authors.lastname: Macdonald
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Walker
authors.forename: David W
authors.initials: DW
authors.lastname: Cope
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena / Q000187:drug effects / Q000502:physiology; D002490:Central Nervous System / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D021122:Protein Subunits / Q000502:physiology; D011963:Receptors, GABA-A / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology
chemical_list: D021122:Protein Subunits; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid