Intracerebroventricularly Administrered Neuropeptide Y and Clonidine: Effects on Feeding Behavior in the Neonatal Chick

Abstract

To clarify the relationship between neuropeptide Y (NPY) and the α₂-adrenergic system on ingestive behavior of the young chick, NPY receptor and α₂-adrenoceptor were stimulated by intracerebroventricular injection of NPY and clonidine (CLON), α₂-receptor agonist, respectively. Central injection of NPY (1, 2.5 or 5μg) significantly increased food intake in a dose-dependent manner in Experiment 1. No additive or synergistic effect was observed when NPY (1μg) and CLON (50ng) were co-administered. However, a significant interaction between NPY (2.5μg) and CLON (50ng) was observed in food intake, implying that an enhanced food intake by NPY was attenuated by co-injection with CLON. These results indicate that α2-adrenoceptors and NPY may interact and regulate food intake within the central nervous system in the young chick, depending their concentrations.