Central administration of galanin stimulates feeding behavior in chicks

Galanin is recognized as one of the orexigenic peptides in the brain of mammals and fishes. The amino acid sequence of chicken galanin and its distribution in the brain are similar to those of mammals, suggesting that the brain galanin might be related to feeding regulation in chicks. The purpose of the present study was to investigate whether intracerebroventricular (ICV) injection of galanin affected feeding behavior of chicks (Gallus gallus). The injection of galanin increased food intake of layer and broiler chicks. We also found that the galanin-induced feeding behavior was attenuated in layer chicks by the co-injection of yohimbine and beta-funaltrexamine, which are the antagonists of adrenergic alpha-2 receptor and opioid mu-receptor, respectively. It is therefore possible that the orexigenic effect of galanin is mediated by these receptors.