EFFECT OF NALOXONE AND ANTIDEPRESSANTS ON HYPERPHAGIA PRODUCED BY PEPTIDE-YY

Central injection of peptide YY (PYY) elicits a powerful feeding respo nse with a short latency in satiated rats. Because of this effect, PYY has been implicated as a neurochemical signal in bulimia nervosa. Ser otonin agonists and opioid antagonists induce anorectic effects upon f eeding behavior in humans and animals. Therefore, to investigate a pos sible interaction between PYY-induced eating and these anorexigenic ag ents rats were given injections of either naloxone (100 mug/3 mul, ICV , and 10 mg/kg, SC), fluoxetine (3-30 mug/3 mul and 5-10 mg/kg, IP), o r clomipramine (3-30 mug/3 mul and 5-10 mg/kg, IP) prior to fourth ven tricular injections of PYY (15 mug/18 mul). Central and peripheral nal oxone and IP but not central injections of fluoxetine blocked PYY-indu ced intake. Clomipramine had no effect. This suggests that PYY-stimula ted feeding may require the action of endogenous opioids and may be in hibited by serotonergic function.