title: The olfactory neuron AWC promotes avoidance of normally palatable food following chronic dietary restriction.
abstract: Changes in metabolic state alter foraging behavior and food preference in animals. Here, I show that normally attractive food becomes repulsive to Caenorhabditis elegans if animals are chronically undernourished as a result of alimentary tract defects. This behavioral plasticity is achieved in two ways: increased food leaving and induction of aversive behavior towards food. A particularly strong food avoider is defective in the chitin synthase that makes the pharyngeal lining. Food avoidance induced by underfeeding is mediated by cGMP signaling in the olfactory neurons AWC and AWB, and the gustatory neurons ASJ and ASK. Food avoidance is enhanced by increased population density and is reduced if the animals are unable to correctly interpret their nutritional state as a result of defects in the AMP kinase or TOR/S6kinase pathways. The TGF-β/DBL-1 pathway suppresses food avoidance and the cellular basis for this is distinct from its role in aversive olfactory learning of harmful food. This study suggests that nutritional state feedback via nutrient sensors, population size and olfactory neurons guides food preference in C. elegans.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK olofsson@mrc-lmb.cam.ac.uk.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Olofsson
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D005247:Feeding Behavior; D009479:Neuropeptides / Q000378:metabolism; D018034:Olfactory Receptor Neurons / Q000378:metabolism*; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C117509:Dbl-1 protein, C elegans; D009479:Neuropeptides; D016212:Transforming Growth Factor beta; D006152:Cyclic GMP
keywords: Aversion; Foraging; Nutritional state; Sensory neurons; TFG-β/DBL-1 pathway