title: Neuronal processing of noxious thermal stimuli mediated by dendritic Ca(2+) influx in Drosophila somatosensory neurons.
abstract: Adequate responses to noxious stimuli causing tissue damages are essential for organismal survival. Class IV neurons in Drosophila larvae are polymodal nociceptors responsible for thermal, mechanical, and light sensation. Importantly, activation of Class IV provoked distinct avoidance behaviors, depending on the inputs. We found that noxious thermal stimuli, but not blue light stimulation, caused a unique pattern of Class IV, which were composed of pauses after high-frequency spike trains and a large Ca(2+) rise in the dendrite (the Ca(2+) transient). Both these responses depended on two TRPA channels and the L-type voltage-gated calcium channel (L-VGCC), showing that the thermosensation provokes Ca(2+) influx. The precipitous fluctuation of firing rate in Class IV neurons enhanced the robust heat avoidance. We hypothesize that the Ca(2+) influx can be a key signal encoding a specific modality.
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Terada
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Matsubara
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
authors.forename: Koun
authors.initials: K
authors.lastname: Onodera
authors.affiliation: Division of Brain Circuits, National Institute for Basic Biology, Okazaki, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsuzaki
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
authors.forename: Tadashi
authors.identifier: http://orcid.org/0000-0001-7204-3606
authors.initials: T
authors.lastname: Uemura
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
authors.forename: Tadao
authors.identifier: http://orcid.org/0000-0002-0507-1495
authors.initials: T
authors.lastname: Usui
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism* / Q000528:radiation effects*; D004330:Drosophila / Q000502:physiology / Q000528:radiation effects*; D006358:Hot Temperature; D009619:Nociceptors / Q000502:physiology / Q000528:radiation effects*; D050051:Transient Receptor Potential Channels / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D002413:Cations, Divalent; D050051:Transient Receptor Potential Channels; D002118:Calcium
keywords: <i>d. melanogaster</i>; ca2+ transient; drosophila; neuroscience; nociception; nocifensive behavior; optogenetics; polymodality