Ontogeny of genetic networks underlying central appetite‐controlling systems in the teleost Atlantic cod (LB830)

Abstract

We examined the distribution of Neuropeptide Y (NPY), cocaine‐ and amphetamine‐regulated transcript (CART) and prepro‐orexin (pOX) in the brain of Atlantic cod by in situ hybridization from onset of exogenous feeding (4days post hatch, dph) to postlarval stage (76dph). All examined genes were expressed from 4dph and displayed temporal and spatial differences in expression during development. pOX mRNA was only expressed in hypothalamus. NPY and CART mRNA expressions had broad distributions in the brain, including telencephalon, diencephalon, and optic tectum. In addition, NPY transcripts were found in the preoptic region, while CART was found in medulla oblongata. New populations of CART positive neurons appeared in olfactory bulb, in the region of the nucleus of medial longitudinal fascicle, and later in midbrain tegmentum. We found several examples of co‐expression (NPY‐CART) and (CART‐pOX). Distributions of NPY and pOX transcripts suggest that telencephalon and hypothalamus are involved in stimulation of feeding in cod. Expression of CART indicates that “satiety centers” are located in hypothalamus, thalamus and medulla oblongata.Grant Funding Source: Supported by Research Council of Norway‐ CODE 199482