Dopamine agonists produce functional recovery from septal lesions which affect hypothalamic defensive attack in cats

Effects of lesions of the lateral septum and subsequent administration of methamphetamine (MAT, 1 mg/kg, i.p.) or apomorphine (APO, 1 mg/kg, i.p.) on thresholds for defensive attack elicited by electrical stimulation of the ventromedial hypothalamic nucleus (VM) were examined. Hissing and directed attack were selected for threshold determination. Thresholds were measured under two situations: one with provocation by a human and the other without it. Electrolytic lesions of the lateral septum enhanced the facilitative influences exerted by the provocation on the thresholds, however, subsequent administration of MAT or APO abolished or tended to abolish the enhancement. The rapid recovery of function was interpreted to have taken place due to excessive dopaminergic inputs to the spared tissue of the lateral septum, and a gating mechanism of neuronal information by dopamine was suggested.