Adenosine A(2A) agonists: A potential new type of atypical antipsychotic

The systemic intraperitoneal (i.p.) administration of the adenosine A(2A) agonist CGS 21680 was found to dose-dependently antagonize spontaneous and amphetamine-induced (1 mg/kg i.p.) motor activity with similar ED50 values (about 0.2 mg/kg). The ratios between the ED50 values for induction of catalepsy and for antagonizing amphetamine-induced motor activity for CGS 21680, haloperidol, and clozapine were 12, 2 and >30, respectively. Furthermore, CGS 21680 was comparably much stronger than haloperidol or clozapine at antagonizing the motor activity induced by phencyclidine (2 mg/kg subcutaneously) than motor activity induced by amphetamine (1 mg/kg i.p.). In conclusion, the present results show a clear ''atypical'' antipsychotic profile of the adenosine A(2A) agonist CGS 21680 in animal models. (C) 1997 American College of Neuropsychopharmacology. Published by Elsevier Science Inc.