PREFRONTAL CORTICAL AND HIPPOCAMPAL MODULATION OF HALOPERIDOL-INDUCEDCATALEPSY AND APOMORPHINE-INDUCED STEREOTYPIC BEHAVIORS IN THE RAT

Effects of prefrontal cortical or hippocampal excitotoxic lesions on b ehavioral parameters related to dopaminergic transmission in the basal ganglia were investigated in the vat. We examined haloperidol-induced catalepsy and apomorphine-induced stereotypic behaviors after iboteni c acid lesions of the medial prefrontal cortex (MPFC), dorsal (DH), or ventral hippocampus (VH) in adult rats. Haloperidol-induced (I mg/kg) catalepsy was decreased in rats with either MPFC or VH but nob DH les ions. While both DH and VH lesioned animals demonstrated a reduction i n apomorphine-induced (0.75 mg/kg) stereotypic behaviors, the VH lesio ned animals also showed an enhancement of locomotor activity. MPFC les ioned rats tended towards potentiation of stereotypic behaviors and re duced locomotion after apomorphine administration, These data indicate that loss of prefrontal cortical or hippocampal modulation leads to a n enhancement of DA transmission within the basal ganglia, though the pattern of augmentation depends on the area lesioned.