title: Metabotropic Glutamate Receptors: MODULATORS OF CONTEXT-DEPENDENT FEEDING BEHAVIOUR IN C. ELEGANS.
abstract: Glutamatergic neurotransmission is evolutionarily conserved across animal phyla. A major class of glutamate receptors consists of the metabotropic glutamate receptors (mGluRs). In C. elegans, three mGluR genes, mgl-1, mgl-2, and mgl-3, are organized into three subgroups, similar to their mammalian counterparts. Cellular reporters identified expression of the mgls in the nervous system of C. elegans and overlapping expression in the pharyngeal microcircuit that controls pharyngeal muscle activity and feeding behavior. The overlapping expression of mgls within this circuit allowed the investigation of receptor signaling per se and in the context of receptor interactions within a neural network that regulates feeding. We utilized the pharmacological manipulation of neuronally regulated pumping of the pharyngeal muscle in the wild-type and mutants to investigate MGL function. This defined a net mgl-1-dependent inhibition of pharyngeal pumping that is modulated by mgl-3 excitation. Optogenetic activation of the pharyngeal glutamatergic inputs combined with electrophysiological recordings from the isolated pharyngeal preparations provided further evidence for a presynaptic mgl-1-dependent regulation of pharyngeal activity. Analysis of mgl-1, mgl-2, and mgl-3 mutant feeding behavior in the intact organism after acute food removal identified a significant role for mgl-1 in the regulation of an adaptive feeding response. Our data describe the molecular and cellular organization of mgl-1, mgl-2, and mgl-3. Pharmacological analysis identified that, in these paradigms, mgl-1 and mgl-3, but not mgl-2, can modulate the pharyngeal microcircuit. Behavioral analysis identified mgl-1 as a significant determinant of the glutamate-dependent modulation of feeding, further highlighting the significance of mGluRs in complex C. elegans behavior.
authors: From the Centre for Biological Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom, jcd@soton.ac.uk.
authors: James
authors: J
authors: Dillon
authors: From the Centre for Biological Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom.
authors: Christopher J
authors: CJ
authors: Franks
authors: the Ramaciotti Centre for Genomics and.
authors: Caitriona
authors: C
authors: Murray
authors: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales 2052, Australia.
authors: Richard J
authors: RJ
authors: Edwards
authors: From the Centre for Biological Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom.
authors: Fernando
authors: F
authors: Calahorro
authors: the Department of Biology, Graduate School of Science, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan, and.
authors: Takeshi
authors: T
authors: Ishihara
authors: the National Institute of Genetics, Yata 1111, Mishima, Shizuoka-ken, 411-8540, Japan.
authors: Isao
authors: I
authors: Katsura
authors: From the Centre for Biological Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom.
authors: Lindy
authors: L
authors: Holden-Dye
authors: From the Centre for Biological Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom, voconno@soton.ac.uk.
authors: Vincent
authors: V
authors: O'Connor
mesh_terms: D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D017931:DNA Primers; D005247:Feeding Behavior; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D018094:Receptors, Metabotropic Glutamate / Q000145:classification / Q000235:genetics / Q000502:physiology*
chemical_list: D017931:DNA Primers; D018094:Receptors, Metabotropic Glutamate
keywords: Caenorhabditis elegans (C. elegans); electrophysiology; invertebrate; metabotropic glutamate receptor (mGluR); optogenetics