Figure 3

Baculovirus mediated expression of NMDAR facilitates sensitivity of NMDAR to ligands of both the glycine- and the glutamate binding sites. (A) Glycine sensitivity of NMDAR-mediated calcium flux in MDL105,519 protected cells. HEK293 cells were transduced with NR1/2 A or NR1/2B baculovirus in the presence of MDL105,519 and NMDAR-mediated calcium flux was measured as described after addition of the indicated concentration of glycine and glutamate. Data represents the mean of the maximal fluorescence ratio ± SEM of three experiments. (B) Glutamate sensitivity of NMDAR-mediated calcium flux in CGP070667 protected cells. HEK293 cells were transduced with NR1/2 A or NR1/2B baculovirus in the presence of CGP070667 and NMDAR-mediated calcium flux was analyzed as in (A). (C,D) Model of protection facilitated sensitivity of NMDAR activity to glycine (C) and glutamate (D). Protection of NMDAR by addition of ligand binding site antagonists protect NMDAR by occupying the ligand binding site and prevent binding of endogenous ligands. After washout of the antagonist, the ligand binding sites become accessible for exogenously added ligand, hence facilitating ligand-sensitivity.