Neuropeptides and the control of food intake in fish

VOLKOFF H; CANOSA LF; UNNIAPPAN S; CERDÁ-REVERTER JM; BERNIER N; KELLY SP; PETER RE

GENERAL AND COMPARATIVE ENDOCRINOLOGY

Año: 2005 vol. 142 p. 3 - 19

0016-6480

The brain, particularly the hypothalamus, integrates input from factors that stimulate (orexigenic) and inhibit (anorexigenic) foodintake. In Wsh, the identiWcation of appetite regulators has been achieved by the use of both peptide injections followed by measurementsof food intake, and by molecular cloning combined with gene expression studies. Neuropeptide Y (NPY) is the most potentorexigenic factor in Wsh. Other orexigenic peptides, orexin A and B and galanin, have been found to interact with NPY in the controlof food intake in an interdependent and coordinated manner. On the other hand cholecystokinin (CCK), cocaine and amphetamineregulatedtranscript (CART), and corticotropin-releasing factor (CRF) are potent anorexigenic factors in Wsh, the latter beinginvolved in stress-related anorexia. CCK and CART have synergistic eVects on food intake and modulate the actions of NPY andorexins. Although leptin has not yet been identiWed in Wsh, administration of mammalian leptin inhibits food intake in goldWsh.Moreover, leptin induces CCK gene expression in the hypothalamus and its actions are mediated at least in part by CCK. Otherorexigenic factors have been identiWed in teleost Wsh, including the agouti-related protein (AgRP) and ghrelin. Additional anorexigenicfactors include bombesin (or gastrin-releasing peptide),
-melanocyte-stimulating hormone (
-MSH), tachykinins, and urotensinI. In goldWsh, nutritional status can modify the expression of mRNAs encoding a number of these peptides, which providesfurther evidence for their roles as appetite regulators: (1) brain mRNA expression of CCK, CART, tachykinins, galanin, ghrelin, andNPY undergo peri-prandial variations; and (2) fasting increases the brain mRNA expression of NPY, AgRP, and ghrelin as well asserum ghrelin levels, and decreases the brain mRNA expression of tachykinins, CART, and CCK. This review will provide an overviewof recent Wndings in this Weld.