title: Dopamine receptor DOP-4 modulates habituation to repetitive photoactivation of a C. elegans polymodal nociceptor.
abstract: Habituation is a highly conserved phenomenon that remains poorly understood at the molecular level. Invertebrate model systems, like Caenorhabditis elegans, can be a powerful tool for investigating this fundamental process. Here we established a high-throughput learning assay that used real-time computer vision software for behavioral tracking and optogenetics for stimulation of the C. elegans polymodal nociceptor, ASH. Photoactivation of ASH with ChR2 elicited backward locomotion and repetitive stimulation altered aspects of the response in a manner consistent with habituation. Recording photocurrents in ASH, we observed no evidence for light adaptation of ChR2. Furthermore, we ruled out fatigue by demonstrating that sensory input from the touch cells could dishabituate the ASH avoidance circuit. Food and dopamine signaling slowed habituation downstream from ASH excitation via D1-like dopamine receptor, DOP-4. This assay allows for large-scale genetic and drug screens investigating mechanisms of nociception modulation.
authors.affiliation: DM Centre for Brain Health, University of British Columbia, Vancouver V6T 2B5, Canada.
authors.forename: Evan L
authors.initials: EL
authors.lastname: Ardiel
authors.affiliation: DM Centre for Brain Health, University of British Columbia, Vancouver V6T 2B5, Canada.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Giles
authors.affiliation: DM Centre for Brain Health, University of British Columbia, Vancouver V6T 2B5, Canada.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Yu
authors.affiliation: Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Theodore H
authors.initials: TH
authors.lastname: Lindsay
authors.affiliation: Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Shawn R
authors.initials: SR
authors.lastname: Lockery
authors.affiliation: DM Centre for Brain Health, University of British Columbia, Vancouver V6T 2B5, Canada Department of Psychology, University of British Columbia, Vancouver V6T 1Z4, Canada crankin@psych.ubc.ca.
authors.forename: Catharine H
authors.initials: CH
authors.lastname: Rankin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001362:Avoidance Learning / Q000502:physiology*; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D000075402:Channelrhodopsins / Q000235:genetics / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D005247:Feeding Behavior / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008124:Locomotion / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009043:Motor Activity / Q000502:physiology; D009154:Mutation; D009619:Nociceptors / Q000166:cytology / Q000378:metabolism*; D062308:Optogenetics; D018408:Patch-Clamp Techniques; D010363:Pattern Recognition, Automated; D010775:Photic Stimulation; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000378:metabolism*; D012677:Sensation / Q000502:physiology
chemical_list: D029742:Caenorhabditis elegans Proteins; D000075402:Channelrhodopsins; C503952:DOP-4 protein, C elegans; D017448:Receptors, Dopamine D2; C088760:cat-2 protein, C elegans; D006899:Mixed Function Oxygenases; D004298:Dopamine