Which drug acts through alpha subunit of GABA?
Correct Answer: Benzodiazepine
Description: The exact subunit structures of native GABA receptors are still unknown, but it is thought that most GABA receptor are composed of α, β and γ subunits that coassemble with some uncertain stoichiometry.
Binding site of GABA is on β -subunit.
Benzodiazepine site is located on the a subunit but the stabilization or completion of that site in the assembled structure requires also the γ subunit.
"The photo - affinity labeling of the benzodiazepine site has confirmed, using isoform - antibodies, to be on an α and not a γ subunit".
So, BZD binding site is present on α subunit at α - γ interface, and both α & γ units are required for BZDs action.
Barbiturates act on Picrotoxin site that is located usually on β- subunit at α -β interface. Both α & β subunit are required for barbiturates action.
GABA → β - subunit.
BZD → α subunit at α - γ interface, i.e. α / γ site.
Barbiturate → β subunit at α - β interface, i.e. α / β site.
Category:
Psychiatry
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