The D2-like receptors (D2R) consist of D2, D3, and D4 receptors. There are two subtypes : D2-short and D2-long. The D2R are mainly located in the striatum, external globus pallidus (GPe), core of NAcc, amygdala, cerebral cortex, hippocampus, and pituitary. The D2R usually inhibits AC activity and hampers cAMP and PKA production levels. Postsynaptic D2 receptors have an essential role in mediating behavioural and extrapyramidal activity .