GLYX-13

GLYX-13 is a nootropic partial agonist of the NMDA receptor - specifically at the glycine binding site. It has been shown to enhance memory and learning in both young adult and learning-impaired, aging rat models. GLYX-13, a tetrapeptide (H-Thr-Pro-Pro-Thr-NH2), readily crosses the blood brain barrier and has been shown to increase Schaffer collateral-CA1 LTP in vitro. In concert with a learning task it has also been shown to elevate gene expression of hippocampal NR1, a subunit of the NMDA receptor, in 3-month-old rats. Neuroprotective effects have also been demonstrated in Mongolian Gerbils by delaying the death of CA1, CA3, and dentate gyrus pyramidal neurons under glucose and oxygen-deprived conditions. Preclinical data indicates that GLYX-13 has a therapeutic index of 500 or more, onset within 20 minutes of administration, and produces antidepressant-like effects lasting approximately two weeks following administration. Currently under development by Naurex Inc, the compound recently completed phase II trials as a treatment for those resistant or non-responsive to traditional antidepressants.

Additionally, GLYX-13 has demonstrated antinociceptive activity, which is of particular interest, as both competitive and noncompetitive NMDA receptor antagonists are ataxic at analgesic doses, while GLYX-13 and other glycine subunit ligands are able to elicit analgesia at sub-ataxic doses.