Brain-penetrant, high-affinity, potent and selective glycine transporter 2 (GlyT-2; GlyT2) inhibitor with higher potency and selectivity than ALX-1393.
ORG 25543 is a brain-penetrant (free brain/plasma ratio = 0.53; 35 min post 2 or 20 mg/kg i.v. in mice), high-affinity, potent and selective glycine transporter 2 (GlyT-2; GlyT2) inhibitor (human & mouse pIC50 = 7.9/ GlyT2 vs <4/GlyT1) with great selectivity over a panel of 56 receptor and channel proteins. ORG 25543 is more potent and selective than the brain-impermeable ALX-1393 (GlyT2/GlyT1 pIC50 = 7.1/5.4) and exhibits high in vivo efficacy in a murine diabetic neuropathic pain model (ED50 = 0.07-0.16 mg/kg i.v.; Emin = 0.01 mg/kg). ORG 25543 is practically irreversible due to its tight-binding nature, suboptimal dosage should be applied in vivo to allow low target occupancy only and minimize acute toxicity.
