D1 and D2 dopamine receptors and circling behavior in rats with unilateral lesion of the entopeduncular nucleus

PAZO JH; MURER MG; SEGAL E

BRAIN RESEARCH BULLETIN

PERGAMON-ELSEVIER SCIENCE LTD

Año: 1993 vol. 30 p. 635 - 639

0361-9230

The role of D1 and D2 striatal dopamine receptors on circling behavior was studied in a normosensitive model obtained by unilateral kainic acid lesion of the entopeduncular nucleus. In this model, the sensitivity of striatal dopamine receptors was preserved, because kainic acid destroyed the neurons of the entopeduncular nucleus and left undamage the fibers of passage and axon terminals. Systemic administration of SKF 38393 to these animals fails to induce circling activity. In contrast, administration of quinpirole elicited rotation toward the lesioned side, which was increased by concurrent injection of SKF 38393. This behavior was inhibited by pretreatment with either a specific D1 (SCH 23390) or D2 (-sulpiride) antagonist. The apomorphine also induced ipsilateral circling that was abolished by pretreatment with D1 or D2 antagonists. The above results suggest that coactivation of both D1 and D2 striatal dopamine receptors are necessary to induce rotation in this normosensitive model.