Involvement of dopaminergic systems in the ventromedial hypothalamic hyperphagia.

The effect of chronic dopamine receptor blockage on ventro-medial hypothalamic lesion induced hyperphagia and obesity was studied. Rats with electrolytic ventromedial hypothalamic (VMH) lesions were treated chronically with either haloperidol (DA antagonist) or vehicle solution. Food intake of rats with VMH lesions fell well below baseline levels. Additionally, these animals started losing body weight within 24 hours of the initiation of treatment and continued to lose weight throughout the treatment period. When the treatment was discontinued these animals resumed overeating and regained body weights. The food intakes and body weights of unlesioned rats treated with either haloperidol or vehicle, and VMH lesioned rats treated with vehicle, were not affected by these treatments.