Sedative but not anxiolytic properties of benzodiazepines ave mediated by the GABA(A) receptor alpha(1) subtype

GInhibitory neurotransmission in the brain is largely mediated by GABA(A) r eceptors. Potentiation of GABA receptor activation through an allosteric be nzodiazepine (BZ) site produces the sedative, anxiolytic, muscle relaxant, anticonvulsant and cognition-impairing effects of clinically used BZs such as diazepam. We created genetically modified mice (alpha(1) H101R) with a d iazepam-insensitive alpha(1) subtype and a selective BZ site ligand, L-838, 417, to explore GABA(A) receptor subtypes mediating specific physiological effects. These two complimentary approaches revealed that the alpha(1) subt ype mediated the sedative, but not the anxiolytic effects of benzodiazepine s. This finding suggests ways to improve anxiolytics and to develop drugs f or other neurological disorders based on their specificity for GABA(A) rece ptor subtypes in distinct neuronal circuits.