Fig. 2. Zuranolone increased potency and E_max of the orthosteric partial agonist P4S at the α₁β₂γ₂ GABA_A receptor.

The E_max of P4S, a GABA_A receptor partial agonist, was 25% of the maximal GABA (100 μM) response, which was doubled by the addition of 200 nM zuranolone to the bath solution. The EC₅₀ for P4S was reduced by nearly half (44.5 μM–25.2 μM) by addition of 200 nM zuranolone. GABA_A receptors were expressed in Ltk cells.