Isolation of type I and type II GABA_A-benzodiazepine receptors by immunoaffinity chromatography

Abstract

Anti-peptide α₁ (1–9) and anti-peptide α₃ (459–467) antibodies coupled to Affigel-10 were used for the isolation of GABA_A receptors containing the α₁-or α₃-subunit, respectively. Both types of GABA_A receptors exhibited a high affinity for [³H]flunitrazepam, and binding of [³H]flunitrazepam was stimulated in the presence of GABA. GABA_A receptors eluted from the anti-peptide α₁ (1–9) immunoaffinity column exhibited a high affinity and those from the anti-peptide α₃ (459–467) columns a low affinity for the type I benzodiazepine receptor-selective ligand Cl 218872, indicating the enrichment of type I and type II GABA_A-benzodiazepine receptors, respectively.