Locomotor activity and a conditioned fear response: correlation with cortical and subcortical binding of the dopamine D-1 receptor antagonist [H-3]SCH 23390

Rat behavior in the open field and conditioned fear response test was corre lated with specific binding of dopamine DI receptor antagonist [H-3]SCH 233 90 within different brain structures assayed with autoradiography. A signif icant positive correlation was found between the ligand binding in the subs tantia nigra pars reticulata and both animal motor activity (r = 0.67, p < 0.05) and the number of entries into the central sector of the open field ( r = 0.59, p < 0.05). On the other hand, rat motility and the central entrie s were negatively correlated with [3H]SCH 23390 binding within the caudate putamen (r = -0.64, p < 0.05 and r = -0.61 p < 0.05, respectively). No corr elation was revealed between the ligand binding in the examined brain areas and freezing reaction in the contextual fear conditioning test. The presen t data indicate For the first time a significant, structure-dependent corre lation between rat motor behavior and the dopamine D-1 receptor ligand bind ing within the nigrostriatal system. NeuroReport 11:3953-3956 (C) 2000 Lipp incott Williams & Wilkins.