Fig. 5.

HCY reduces desensitization of GluN2A and GluN2B, but not GluN2D NMDAR currents, at 1 μM GLY, without affecting NMDAR decay kinetics. A: raising the ambient [GLY] from 200 nM to 1 μM prevented HCY from modulating peak amplitude of GluN2A- and GluN2B-mediated currents in HEK cells (N = 4, 5). However, HCY continued to enhance charge transfer through GluN2A- and GluN2B-containing receptors in 1 μM GLY. GluN2D (N = 5) is completely saturated at 1 μM GLY. B: although HCY was effective in reducing desensitization in GluN2A HEK cells, it did not alter deactivation kinetics after 1-ms pulses of glutamate, indicating an effect on desensitized states only.