From:  Role of dopamine receptor heteromerization in preclinical models of addiction and other psychiatric disorders

Modulation and functions of DAR-NMDAR heteromerization in response to cocaine. Schematic representation of cocaine-evoked (A) D1R-NMDAR and (C) D2R-NMDAR heteromerization and associated downstream signaling cascades. Impact of D1R-NMDAR (B) and D2R-NMDAR (D) disruption on molecular, cellular, and behavioral adaptations induced by cocaine. See main text for details. NAc: nucleus accumbens; D1R: DA receptor type 1; MSN: medium sized-spiny neurons; NMDAR: N-methyl-D-aspartate glutamate receptor; ERK: extracellular signal-regulated kinase