Figure 1.

Schematic model representing the main components of the HPI and HSC axis that are activated during the physiological stress response and could be involved in the reduced food intake response under stress conditions. The main factors involved in the homeostatic control of food intake in teleost fish are also represented. Black thick arrows indicate enhanced or decreased levels under stress conditions. Under stress conditions, there is an increase of the dopaminergic and serotonergic activity in the fish brain. HPI and HSC axis are activated leading to the increase of several components with known anorexigenic properties (in red). On the other hand, orexigenic components (in green) are increased (neuropeptides NPY and AgRP) or decreased (ghrelin) under stress conditions. Furhermore, nutrient signals are not properly sensed by the hypothalamus. All this information is integrated in the hypothalamus resulting in decreased food intake. ACTH, adrenocortitropic hormone; AgRP, Agouti-related peptide; AVT, arginine vasotocin; CART, cocaine- and amphetamine-related transcript; CCK, cholecystokinin;CNSS, caudal neurosecretory system; CRF, corticotrophin releasing factor; DA, dopamine; DOPAC, 3,4-dihydroxyphenylacetic Acid; E, epinephrine; GHRL, ghrelin; GLP1 glucagon like peptide 1; HPI, hypothalamus- pituitary-interrenal axis; HSC, hypothalamus-sympathetic system-chromaffin tissue; NE, norepinephrine; NLT, nucleus lateral tuberal; NPY, neuropeptide Y; ORX, orexin; POMC, pro-opio melanocortin; UI, Urotensin I; 5HIAA, 5-hydroxyindole-3-acetic acid; 5HT, serotonin.