Effect of food deprivation on MCH and GnRH variants in the cichlid fish Cichlasoma dimerus. A morphological and functional study

PEREZ SIRKIN, D.; CÁNEPA, M.C.; FERNANDINO, J.I.; DELGADIN, T.H.; FOSSATI, M.; PANDOLFI, M.; SOMOZA, G.M.; VIZZIO, P.G.

Buenos Aires

Simposio; 7th International Symposium on Fish Endocrinology; 2012

In vertebrates, the regulation of appetite is complex and involves the brain andperipheral signals. There are several neuropeptides implicated in the regulation ofnutrition and reproduction, suggesting a clear link between feeding and reproductivefunctions. In particular, both chicken GnRH II (GnRH-II) and MCH have been involvedin the regulation of food intake in teleost fish. The main aims of the present studywere to examine the effect of fasting over theMCH and the three GnRH variantsexpression and a possible interaction between these peptides in C. dimerus. Wefirst obtained the full length sequence of the GnRH variants. Then, we studied theeffect of fasting by RTqPCR. One-week fasted fish had lower expression levels ofboth GnRH-II and MCH compared to the fed ones; however, 3 and 4 week fasted fishshowed no statistical differences compared to the control group. Concomitantly, bydouble label immunofluorescence and confocal microscopy we could demonstratethat GnRH-II fibers are in contact with MCH neurons in the NLT. No association wasfound between MCH and the other GnRH variants. Taken together, these resultssuggest that GnRH-II and MCH may have an anorexic function in C. dimerus and thatthere is a functional association between these two neuronal systems.