Recent advances in the regulation of feeding behavior by neuropeptides in fish

The hypothalamus and brain stem in vertebrates play an important role in feeding regulation. Many kinds of neuropeptides have been implicated in the regulation of food intake and energy homeostasis in rodents. In addition to rodents, however, the goldfish has been widely used as an animal model to investigate the effects of neuropeptides on feeding behavior. Although several neuropeptides exert similar effects on feeding behavior in goldfish and in rodents, marked differences have been reported for other neuropeptides. For instance, melanin-concentrating hormone, which exerts orexigenic activity in rodents, acts as an anorexigenic neuropeptide via the α-melanocyte- stimulating hormone signaling pathway by neuronal interaction in goldfish. These observations indicate that, while the same series of neuropeptides and their receptor systems are involved in the control of feeding behavior throughout the vertebrate phylum, major differences may occur in their mode of action between fish and mammals. This paper gives a mini review of recent advances in the regulation of feeding behavior by neuropeptides in fish, with a focus on recent studies in goldfish.