Adenosine A2A receptors modulate the dopamine D2 receptor-mediated inhibition of synaptic transmission in the mouse prefrontal cortex.

Abstract

Prefrontal cortex (PFC) circuits are modulated by dopamine acting on D1 - and D2 -like receptors, which are pharmacologically exploited to manage neuropsychiatric conditions. Adenosine A2A receptors (A2A R) also control PFC-related responses and A2A R antagonists are potential anti-psychotic drugs. As tight antagonistic A2A R-D2 R and synergistic A2A R-D1 R interactions occur in other brain regions, we now investigated the crosstalk between A2A R and D1 /D2 R controlling synaptic transmission between layers II/III and V in mouse PFC coronal slices. Dopamine decreased synaptic transmission, a presynaptic effect based on the parallel increase in paired-pulse responses. Dopamine inhibition was prevented by the D2 R-like antagonist sulpiride but not by the D1 R antagonist SCH23390 and was mimicked by the D2 R agonist sumanirole, but not by the agonists of either D4 R (A-412997) or D3 R (PD128907). Dopamine inhibition was prevented by the A2A R antagonist, SCH58261, and attenuated in A2A R knockout mice. Accordingly, triple-labelling immunocytochemistry experiments revealed the co-localization of A2A R and D2 R immunoreactivity in glutamatergic (vGluT1-positive) nerve terminals of the PFC. This reported positive A2A R-D2 R interaction controlling PFC synaptic transmission provides a mechanistic justification for the anti-psychotic potential of A2A R antagonists.