We hypothesize that ceramides are involved in the regulation of food intake in fish. Therefore, we assessed in rainbow trout (Oncorhynchus mykiss) the effects of intracerebroventricular (ICV) treatment with C6:0 ceramide on food intake. In a second experiment, we assessed the effects in brain areas of ceramide treatment on neuropeptide expression, fatty acid sensing systems, and cellular signaling pathways. Ceramide treatment induced a decrease in food intake, a response opposed to the orexigenic effect described in mammals, which can be related to enhanced mRNA abundance of CART and POMC and decreased mRNA abundance of AgRP and NPY. Fatty acid sensing systems appear to be inactivated by ceramide treatment. The mRNA abundance of integrative sensors AMPK and SIRT-1, and the phosphorylation status of cellular signaling pathways dependent on Akt, AMPK, mTOR, and Fox01 are generally activated by ceramide treatment. However, Tthere are differences between hypothalamus and hindbrain in the response phosphorylation status of AMPK (decreased in hypothalamus and increased in hindbrain), mTOR (decreased in hypothalamus and increased in hindbrain), and Fox01 (increased in hypothalamus and decreased in hindbrain) to ceramide treatment. The results suggest that ceramides are involved in the regulation of food intake in rainbow trout through mechanisms comparable to those characterized previously in mammals in some cases but not in others.
- rainbow trout
- food intake
- Copyright © 2016, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology