Enhancement of the binding of 3H-diazepam to rat brain membranes in vitro by SQ 20009, A novel anxiolytic, gamma-aminobutyric acid (GABA) and muscimol.

SQ 20009, a compound with anxiolytic-like activity, was found to cause an enhancement of the binding of ³H-diazepam to rat brain membranes in a concentration-dependent manner with inhibition of binding occuring at 10^?4 M. Both GABA and the GABA agonist, muscimol, were also found to enhance ³H-diazepam binding while the GABA antagonist (+)-bicuculline decreased binding. The effects of SQ 20009, the GABA agonists and (+)-bicuculline were reflected as a change in the affinity rather than number of binding sites. The effects of SQ 20009 and GABA and muscimol are discussed in terms of an interaction with an endogenous diazepam-like factor.