Effects Of Phoenixin-14 On Food Intake And Gastrointestinal Motility In Mice

Phoenixin is a newly identified endogenous peptide in neural and non-neural tissue, which is highly conserved in multiple species. Phoenixin-14, one of the endogenous active iso-forms, is a C-terminally amidated peptide consisting of 14 amino acids. The initial study has revealed that phoenixin-14 can modulate the expression of the gonadotropic releasing hormone(GnRH) receptor to regulate pituitary gonadotrophin secretion, which was involved in the regulation of the reproductive system. Subsequent studies showed that phoenixin-14 also have other physiological functions. Intracerebroventricular(i.c.v.) administration of phoenixin-14 in mice relieved acetic acid-induced pain dose-dependently. Phoenixin-14 by subcutaneously injection to the neck can provoke repetitive scratching to the back of the neck in mice. Furthermore, central administration of phoenixin-14 not only promoted memory formation, but also prolonged memory retention. Recent reports suggest that phoenixin-14 is highly co-expressed with anorexia peptide nesfatin-1 in hypothalamus. However, the effects of phoenixin-14 on food intake and gastrointestinal motility have not been well characterized.The present study was designed to investigate the effects of phoenixin-14 on food intake and gastrointestinal motility in mice. After i.c.v administration of different doses phoenixin-14, the food intake and gastric emptying rate were determined at different times. Meanwhile, charcoal driving in small intestine was used to observe the percentage of pushing carbonic powder in small intestine. The results indicated that i.c.v. administration of phoenixin-14 increased food intake, gastric emptying rate and gastrointestinal transit rate in a dose-related manner in mice. An hour after injected of phoenixin-14(25, 50 and 100 nmol/mouse), food intake was increased by 13.51%,20%, 25.58%. Meanwhile, gastric emptying rate was increased by 9.92%, 18.87%, 23.56%, but had little changes in 2 h. In addition, the rate of gastrointestinal transit was facilitated by 12.49%, 19.95%, 26.23%. The effects of phoenixin-14 can be reversed by melanocortin receptor agonist MTâ…¡, suggesting that the central melanocortin system may be involved in the food intake and gastrointestinal effects induced by central injection of phoenixin-14. These results indicated that phoenixin-14 may play important roles in regulating food intake and gastrointestinal function.