Role of Central Cannabinoidergic System on Ghrelin-Induced Hypophagia in Layer-Type Neonatal Chicken

Feeding behavior is regulated via a complex network which interacts through diverse signals from central and peripheral tissues. The main purpose of the current study was to determine the role of central cannabinoidergic (CBergic) system on ghrelin-induced hypophagia in 3-h food deprived (FD3) neonatal chicken. In experiment 1, chicks were ICV injected with control solution, ghrelin (0.6 nmol), SR141716A (selective CB1 receptors antagonist, 6.25 µg) and ghrelin + SR141716A. In experiment 2, chickens received ICV injection of (A) control solution, ghrelin (0.6 nmol), AM630 (selective CB2 receptors antagonist, 1.25 µg) and ghrelin + AM630. In experiment 3, chickens were ICV injected with control solution, 2-AG (selective CB1 receptors agonist, 2µg), GSK1614343 (selective ghrelin receptors antagonist, 6 nmol) and 2-AG + GSK1614343. In experiment 4, the birds received control solution, CB65 (selective CB2 receptors agonist, 6.25 µg), CB65 + GSK1614343. Then the cumulative food intake was measured until 120 min post injection. According to the results, ICV injection of the ghrelin, significantly decreased cumulative food intake (P<0.05). Co-injection of the ghrelin + SR141716A and/or ghrelin + AM630 significantly amplified ghrelin-induced hypophagia compared to control group (P<0.05). Hyperphagia observed by ICV injection of the 2-AG (2 µg) (P<0.05). Co-injection of the 2-AG + GSK1614343 increased food intake compared to control group (P<0.05). ICV injection of the CB65 (1.25 µg) significantly increased food intake (P<0.05). Also, co-injection of the CB65 + GSK1614343 significantly amplified cumulative food intake in FD3 neonatal layer-type chicken (P<0.05). These results suggested ghrelin-induced hypophagia mediates via CB1 and CB2 receptors in neonatal layer-type chicken