Behavioral performance at early (4 weeks) and later (6 months) stages in rats with unilateral medial forebrain bundle and striatal 6-hydroxydopamine lesions

Abstract

Our previous studies showed differences in striatal D2 receptor functional activity between two different rat parkinsonian models, with lesions induced by 6-hydroxydopamine injection in the striatum and in the medial forebrain bundle (MFB) at both early (4 weeks) and later (6 months) stages after lesioning. The present study compared behavioral changes, including rotational movements induced by metham-phetamine and bromocriptine, and the stepping test, in both models at both stages. No differences in behavioral performance were observed between the early and later stages in both striatal and MFB lesion models, whereas simultaneous D2 receptor study showed dynamic change in D2 receptors in MFB lesion rats. Behavioral characteristics might be controlled by comprehensive effects of the whole dopaminer-gic system, instead of variation in a few parameters of the dopaminergic system. More behavioral tests of different mechanisms with simultaneous molecular studies are needed for evaluation of parkinsoni-an animal models and the efficacy of treatments.