Extrasynaptic GABAA Receptors: Form, Pharmacology, and Function

• Published in: The Journal of neuroscience 2009-10, Vol.29 (41), p.12757-12763
• Main Authors: Belelli, Delia, Harrison, Neil L, Maguire, Jamie, Macdonald, Robert L, Walker, Matthew C, Cope, David W
• Format: Article
• Language: English
• Subjects: Animals; Biophysical Phenomena - drug effects; Biophysical Phenomena - physiology; Central Nervous System - drug effects; Central Nervous System - physiology; Female; gamma-Aminobutyric Acid - metabolism; gamma-Aminobutyric Acid - pharmacology; Humans; Male; Neural Inhibition - drug effects; Neural Inhibition - physiology; Pregnancy; Presynaptic Terminals - drug effects; Presynaptic Terminals - metabolism; Protein Subunits - physiology; Receptors, GABA-A - physiology; Symposia and Mini-Symposia; Synaptic Transmission - drug effects; Synaptic Transmission - physiology
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/JNEUROSCI.3340-09.2009

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.