Extrasynaptic GABAA receptors: form, pharmacology, and function.
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.
Belelli
Delia
D
Division of Medical Sciences, Centre for Neuroscience, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, United Kingdom.
Harrison
Neil L
NL
Maguire
Jamie
J
Macdonald
Robert L
RL
Walker
Matthew C
MC
Cope
David W
DW
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
D021122:Protein Subunits; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid