Adenosinergic and dopaminergic interaction in nigrostriatum in FeCl3-induced model of parkinsonism in rats.

The effect of adenosine modulating drugs was studied in the FeCl3-induced model of parkinsonism in rats. In rats bearing unilateral FeCl3 induced lesion of the dopaminergic nigrostriatal pathway, stimulation of adenosine receptors with adenosine, dose-dependently reduced the ipsilateral rotations induced by apomorphine. A specific agonist of adenosine A2A receptor, CGS-21680, also completely blocked the rotations while the specific A2 receptor antagonist, CGS-15943A, potentiated rotations induced by apomorphine. The nonspecific adenosine antagonist, theophylline (50 mg/kg i.p.) potentiated stereotype behavior although blocking rotations. This study provides evidence for a negative postsynaptic interaction between dopamine and adenosine receptors.