STIMULATION OF ADENOSINE A(2A) RECEPTORS IN THE RAT STRIATUM INDUCES CATALEPSY THAT IS REVERSED BY ANTAGONISTS OF N-METHYL-D-ASPARTATE RECEPTORS

Bilateral infusion of the selective adenosine A(2a) agonist CGS 21680C (1 mu g per side) into the anterodorsal striatum of rats produced pro found catalepsy. Intraperitoneal coadministration of the non-competiti ve N-methyl-D-aspartate (NMDA) antagonist dizocilpine (0.16 mg/kg) or the competitive NMDA antagonist CGP 37849 (4 mg/kg) completely reverse d CGS 21680C-induced catalepsy, while lower doses of both NMDA antagon ists induced no or only weak anticataleptic effects. The adenosine A(2 a) receptor localization to striatopallidal neurons suggests that a se lective activation of the striatopallidal efferent pathway is involved in the expression of catalepsy induced by intrastriatal infusion of C GS 21680C. In addition, striatopallidal neurons seem to be an importan t neuronal substrate of the anticataleptic effects of NMDA antagonists .