DRD2 and cocaine use disorder: The adenosine A2A receptor (A2AR)-dopamine D2 receptor (D2R) heteroreceptor complexes and their allosteric receptor-receptor interactions in the ventral striatal-pallidal GABA antireward neurons are of high relevance for understanding cocaine reward and cocaine use disorder (Trifilieff et al., 2011; Pintsuk et al., 2016; Borroto-Escuela et al., 2018a; Borroto-Escuela et al., 2018b; Wydra et al., 2020; Zhu et al., 2020).