Stimulation of adenosine A 2a receptors in the rat striatum induces catalepsy that is reversed by antagonists of N-methyl- D-aspartate receptors

Abstract

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