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Summary: articles
nature neuroscience · volume 4 no 5 · may 2001 477
Ligand-gated ion channels are allosteric proteins that couple
neurotransmitter binding to the opening and subsequent
desensitization of an ion channel that is part of the receptor
protein. A complete understanding of how ligand binding con-
trols channel gating requires not only identification of bind-
ing site and channel-lining residues, but also knowledge of the
conformational movements that occur within these domains
during channel activation.
GABAA receptors are members of the ligand-gated ion chan-
nel gene superfamily that includes receptors for glycine, acetyl-
choline, serotonin and, in invertebrates, glutamate15. Drugs used
clinically for general anesthesia, and those used to treat anxiety
disorders and epilepsy, target GABAA receptors1,3,6, which are
formed by the pseudosymmetrical assembly of five homologous
subunits around a central transmembrane channel. Co-expres-
sion of and subunits mainly forms receptors with a subunit
stoichiometry of two and three 7,8; however, a small subpop-
ulation with other stoichiometries such as three and two may
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