MOTOR DEPRESSANT EFFECTS MEDIATED BY DOPAMINE D-2 AND ADENOSINE A(2A)RECEPTORS IN THE NUCLEUS-ACCUMBENS AND THE CAUDATE-PUTAMEN

We compared hypolocomotion and catalepsy mediated by striatal dopamine D-2 and adenosine A(2A) receptors using microinfusions of the adenosi ne A(2A) receptor agonist 2-p-(2-carboxyethyl) phenethylamino-5'-N-eth ylcarboxamidoadenosine hydrochloride (CGS21680) and the dopamine D-2 r eceptor antagonist raclopride into the nucleus accumbens and the cauda te-putamen. The effective doses (ED(25/50)) of CGS21680 and raclopride which produced equivalent reductions of spontaneous locomotion after microinfusion into the nucleus accumbens were found to induce similar degrees of catalepsy after microinfusion into the caudate-putamen. Thi s comparable, little separation of the effective doses of a dopamine D -2 receptor antagonist and an adenosine A(2A) receptor agonist to prod uce locomotor inhibition and catalepsy support the idea that adenosine A(2A) receptor agonists as potential antipsychotic agents may have a similiar therapeutic profile as dopamine D-2 receptor antagonists. (C) Elsevier Science B.V.