Characterization of the Pharmacology of Recombinant Human GABAA Receptor Complexes Containing A2（α1 isoleucin 148 to valine） or A2（α1 asparatic acid 151 to asparagin） or A2 （α1 threonine 149 to glutamine） in Combination with β2γ2s Subu

Recombinant human GABAA receptors were investigated in vitro by coexpression of cDNAs coding for α1,β2 and γ2 subunits in the baculovirus/Sf-9 insect cell system,A single amino acid exchange α1(asparatic acid 151 to asparagin or α1(threonine 149 to glutamine) in the N-terminal,extracellular part of the α1 subunit induced about 10 fold decrease in an antagonist pitrazepine affinity.Other GABAA receptor ligands had little difference in their affinity.It was likely that 151 and 149 amino acid residues were essential for the binding affinity and efficacy of pitrazepine to GABAA receptor combinations containiαααααααααng an α1 subunit.