ANORECTIC AND NEUROCHEMICAL EFFECTS OF PITUITARY ADENYLATE-CYCLASE ACTIVATING POLYPEPTIDE IN RATS

Pretreatment of rats with intrahypothalamic injections of pituitary ad enylate cyclase activating peptide (PACAP) 10 min prior to the injecti on of neuropeptide Y (NPY) significantly reduced food and water intake during the 4-h measurement period. Intrahypothalamic injection of PAC AP in schedule-fed rats also reduced food and water intake for 2 h. A smaller 1-h reduction of water intake was observed in water-deprived r ats, suggesting that the anticonsummatory effects of PACAP were primar ily against food intake. PACAP treatment did not alter hypothalamic co ncentration of NPY, nor were neurotransmitters, precursors, or metabol ites altered substantially in corpus striatum or nucleus accumbens reg ions. These results demonstrate primary anorectic effects of intrahypo thalamic injection of PACAP. The demonstration of these anorectic effe cts may suggest a role of cyclic AMP activation and inhibition in the control of satiety and hunger.