PNU-107484A is a GABA A receptor ligand that exhibits target activity mechanisms dependent on α isoforms. In the α1β2γ2 subtype, PNU-107484A acts as a positive allosteric modulator, enhancing GABA -induced Cl - currents, while it inhibits the currents in the α3β2γ2 and α6β2γ2 subtypes. The half-maximal concentrations for the α1β2γ2, α3β2γ2, and α6β2γ2 subtypes are 3.1, 4.2, and 3.5 μM, respectively. PNU-107484A can be used as a probe to investigate the physiological roles of different α isoform subtypes.