MRK-623 (Compound 14k) is a potent, orally active agonist of the GABA A receptor with high affinity for subunits α1, α2, α3, and α5, exhibiting Ki values of 0.85 nM, 3.7 nM, 4.0 nM, and 0.53 nM, respectively. Notably, MRK-623 demonstrates anxiolytic effects [1].

MRK-623 demonstrates effectiveness on human GABAA receptor subtypes, which are expressed in L(tk-) cells. This has been measured using whole cell patch-clamp electrophysiology [1].

MRK-623, administered via oral gavage at dosages of 0.3, 1, and 3 mg/kg on a single occasion, demonstrates anxiolytic effects in rats as measured by the elevated plus maze assay [1]. Specifically, at a dosage of 3 mg/kg, MRK-623 achieved 78% benzodiazepine (BZ) site occupancy, with an inhibitory dose 50 (ID 50) identified at 0.8 mg/kg.