Modulation of striatal adenosine A1 and A2 receptors induces rotational behaviour in response to dopaminergic stimulation in intact rats.

The intraperitoneal injection of d-amphetamine (5 mg/kg i.p.), preceded (10 min before) by intrastriatal injection of an adenosine A2 receptor agonist (CGS 21680, 5-10 micrograms) or followed (5 min later) by an intrastriatal adenosine A1 receptor agonist (N6-cyclopentyladenosine, CPA, 30 micrograms), induced ipsilateral rotations in rats. The opposite effect (contralateral rotations) was observed with adenosine receptor antagonists (A2 antagonist, 3,7-dimethyl-1-propargylxanthine, DMPX, 10 micrograms; A1 antagonist, 8-cyclopentyl-1,3-dimethylxanthine, CPT, 2.5 micrograms). These results confirm that both adenosine A2 and A1 receptors modulate striatal dopaminergic neurotransmission.