Requirement of PSD-95 for dopamine D1 receptor modulating glutamate NR1a/NR2B receptor function

Aim:To elucidate the role of scaffold protein postsynaptic density (PSD)-95 inthe dopamine D1receptor (D1R)-modulated NR1a/NR2B receptor response.Methods:The human embryonic kidney 293 cells expressing D1R (tagged with theenhanced yellow fluorescent protein) and NR1a/NR2B with or without co-expres-sion of PSD-95 were used in the experiments.The Ca2+influx measured by imagingtechnique was employed to monitor N-methyl-D-aspartic acid receptors (NMDAR)function.Results:The application of dopamine (DA,100 μmol/L) did not alterglutamate/glycine (Glu/Gly)-induced NMDAR-mediated Ca2+influx in cells onlyexpressing the D1R/NR1a/NR2B receptor.However,DA increased Glu/Gly-induced Ca2+influx in a concentration-dependent manner while the cells wereco-expressed with PSD-95.D1R-stimulated Ca2+influx was inhibited by a selectiveD1R antagonist SCH23390.Moreover,pre-incubation with either the proteinkinase A (PKA) inhibitor H89,or the protein kinase C (PKC) inhibitor chelerythrineattenuated D1R-enhanced Ca2+influx induced by the N-methyl-D-aspartic acid(NMDA) agonist.The results clearly indicate that D1R-modulated NR1a/NR2Breceptor function depends on PSD-95 and is subjected to the regulation of PKAand PKC.Conclusion:The present study provides the first evidence that PSD-95is essential in D1R-regulated NR1a/NR2B receptor function.