Neural mechanisms underlying feeding drive

Abstract

Changes in the brain activity patterns are the neural correlates underlying behavioural flexibility. Previous studies con ducted in our lab oratory have identified CART as a major anorexia inducing agent in zebrafish. CART induces neuronal activity in the medial region of dorsal telencephalon (Dm) by potentiating the NMDA receptor activit y rendering the Dm neurons hyperexcitab le . Herein , we used CART as an entry point and identified the neural circuitries that regulate feeding drive in zebrafish, Danio rerio . We found that the CART and NPY neurons , at discrete sites in hypothalamus and in the ventral telencephalon are the major gluco - responsive neurons in the brain. T hese apparently ener gy sensing neurons project to Dm and seem to modulate the activity of the constituent neurons. Both NPY and CART act through parallel , yet opposing, mechanisms and alter the neuronal activity in Dm leading to a switch - like action between the satiety and hunger states . Each of these state s last over an extended period of time and may be attributed to the biochemical modulation of the neuronal activity. Here, we describe the possible mechanisms , and their neuroanatomical correlates, through which these neuromodulators influence food intake . Sensory modalities like olfaction also play a major role in sensing the energy status and influencing energy acquisition . NPY in the olfactory system seems to mod ulat e the feeding drive in an energy dependent manner . In brief, Dm emerges as an integration centre of CART and NPY mediated interoceptive inputs, whose activity may determine the feeding state.