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Adenosine receptors (AR) are a family of G-protein coupled receptors, comprised of four members, named A₁, A_2A, A_2B, and A₃ receptors, found widely distributed in almost all human body tissues and organs. To date, they are known to participate in a large variety of physiopathological responses, which include vasodilation, pain, and inflammation. In particular, in the central nervous system (CNS), adenosine acts as a neuromodulator, exerting different functions depending on the type of AR and consequent cellular signaling involved. In terms of molecular pathways and second messengers involved, A₁ and A₃ receptors inhibit adenylyl cyclase (AC), through G_i/o proteins, while A_2A and A_2B receptors stimulate it through G_s proteins. In the CNS, A₁ receptors are widely distributed in the cortex, hippocampus, and cerebellum, A_2A receptors are localized mainly in the striatum and olfactory bulb, while A_2B and A₃ receptors are found at low levels of expression. In addition, AR are able to form heteromers, both among themselves (e.g., A₁/A_2A), as well as with other subtypes (e.g., A_2A/D₂), opening a whole range of possibilities in the field of the pharmacology of AR. Nowadays, we know that adenosine, by acting on adenosine A₁ and A_2A receptors, is known to antagonistically modulate dopaminergic neurotransmission and therefore reward systems, being A₁ receptors colocalized in heteromeric complexes with D₁ receptors, and A_2A receptors with D₂ receptors. This review documents the present state of knowledge of the contribution of AR, particularly A₁ and A_2A, to psychostimulants-mediated effects, including locomotor activity …