DRD1 and drug-induced dyskinesia: PSD-95 acts as a postsynaptic scaffold, interacting with both D1R and N-methyl-D-aspartate (NMDA) glutamate receptors (Zhang et al. 2009; Fiorentini et al. 2003) (see article by Mellone and Gardoni in this issue for a detailed description of the involvement of glutamate receptors in dyskinesia).