Differential behavioral activities from anterior and posterior hypothalamic lesions in the rat

Bilateral 6-hydroxydopamine injections into the anterolateral (AL) or posterolateral (PL) portions of the hypothalamus produced hypokinesia, catalepsy, rigidity and severe weight losses due to aphagia and adipsia. Subcutaneous administration of apomorphine, 1 mg/kg, 48 hr after 6-OHDA injections reversed temporarily the hypokinesia in both AL and PL 6-OHDA groups. However, qualitative and quantitative differences in the behavioral responses to the drug were observed. Motor activity as measured by photocell counts was significantly greater in AL 6-OHDA rats. Apomorphine induced stereotyped behavior in both groups; however, the predominant behavioral responses were oral stereotypies in PL 6-OHDA animals and sniffing in AL 6-OHDA rats.