Multiparameter Optimization of Naphthyridine Derivatives as Selective α5-GABAA Receptor Negative Allosteric Modulators.

The discovery and characterization of novel naphthyridine derivatives with selective α5-GABAAR negative allosteric modulator (NAM) activity are disclosed. Utilizing a scaffold-hopping strategy, fused [6 + 6] bicyclic scaffolds were designed and synthesized. Among these, 1,6-naphthyridinones were identified as potent and selective α5-GABAAR NAMs with metabolic stability, cardiac safety, and beneficial intellectual property (IP) issues. Relocation of the oxo acceptor function and subsequent modulation of the physicochemical properties resulted in novel 1,6-naphthyridines with improved profile, combining good potency, selectivity, ADME, and safety properties. Besides this, compound 20, having the most balanced profile, provided in vivo proof of concept (POC) for the new scaffold in two animal models of cognitive impairment associated with schizophrenia (CIAS).

Antagonism of AMPA receptors produces anxiolytic-like behavior in rodents: effects of GYKI 52466 and its novel analogues.

RATIONALE: Although emerging number of data supports the role of glutamate receptors and the potential of their antagonists in anxiety disorders, the involvement of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptors in anxiety is less well characterized. OBJECTIVE: To evaluate the anxiolytic potential of 2,3-benzodiazepine (2,3BDZ) type AMPA receptor antagonists in various models of anxiety. MATERIALS AND METHODS: Whole-cell currents, hippocampal field potentials, elevated plus maze (EPM), meta-chlorophenylpiperazine (mCPP)-induced anxiety model, Vogel test in rats and light-dark test (LD) in mice were used to determine AMPA/kainite receptor properties and anxiolytic-like activity of a series of 2,3BDZ-type compounds. RESULTS: The reference compound GYKI 52466 was proved active in two anxiety models in non-sedative doses: minimal effective dose (MED) was especially low in EPM (0.01 mg/kg) GYKI 53405 and GYKI 53655 showed anxiolytic-like activity in two tests (EPM and mCPP). EGIS-8332 was active in EPM and LD while EGIS-9637 showed anxiolytic-like potency in EPM, mCPP and Vogel model. EGIS-10608 was the most effective compound among 2,3BDZs tested in EPM and Vogel models (MEDs are 0.01 and 2.5 mg/kg, respectively). 2,3BDZs were active in anxiety models at doses lower than those produced sedative effects. NBQX showed anxiolytic-like activity in EPM only (3 mg/kg). CONCLUSIONS: The results show that non-competitive AMPA receptor antagonists can profoundly block anxiety-like behavior in rodents independently from their motor depressant activity. However, the sedative properties at higher doses might limit their therapeutic utility as new anxiolytic drugs.