GRIN2B and depressive disorder: Other iGluR modulators, including GluN2B-specific NMDA receptor antagonists (CP-101/MK-0657) (Ibrahim et al. 2012; Preskorn et al. 2008) and NMDA receptor glycine-site partial agonists (D-cycloserine/GLYX-13) (Depression 2015; Phase), are also under various stages of clinical trials and the results appear to be acceptable to some extent.