RESUMO
The brain-gut peptide ghrelin, a endogenous ligand for the growth hormone secretagogue hormone receptor, is mainly produced by gastric cells in the periphery, regulating energy metabolism via stimulating the appetite. Inside the brain, ghrelin is mainly expressed in the pituitary and in the hypothalamic arcuate nucleus, regulating the synthesis and secretion of neuropeptides that are correlated with feeding behavior, reproduction, and stress responses. Recently, more and more researches focused on the regulating roles of ghrelin on learning and memory, and mood regulation have indicated that ghrelin may inhibit neuronal apoptosis, improve cognitive function, and regulate the activities of neuroendocrine systems such as the hypothalamo-pituitary-adrenal axis and the hypothalamo-pituitary-gonadal axis thus get involved in the pathogenesis of neuropsychiatric diseases. The aim of this review is to summarize the main findings in this field, with the purpose of promoting further studies on the role of ghrelin in the brain.