Hyperphagia and Increased Growth in Rats After Intraventricular Injection of 5,7-Dihydroxytryptamine

Abstract

Juvenile male rats given intracerebroventricular injections of 5,7-dihydroxytryptamine, following treatment with desmethylimipramine, maintained body weight gains of 5 to 6 grams per day into adulthood and grew much larger than control rats. Biochemical analyses of brain tissue obtained 50 to 140 days after the injections revealed 60 to 86% depletions of telencephalic 5-hydroxytryptamine, with catecholamine levels unchanged. Hyperphagia did not develop despite comparable losses of 5-hydroxytryptamine when the pretreatment was withheld, perhaps because substantial depletions of norepinephrine occurred as well.