title: Touch responsiveness in zebrafish requires voltage-gated calcium channel 2.1b.
abstract: The molecular and physiological basis of the touch-unresponsive zebrafish mutant fakir has remained elusive. Here we report that the fakir phenotype is caused by a missense mutation in the gene encoding voltage-gated calcium channel 2.1b (CACNA1Ab). Injection of RNA encoding wild-type CaV2.1 restores touch responsiveness in fakir mutants, whereas knockdown of CACNA1Ab via morpholino oligonucleotides recapitulates the fakir mutant phenotype. Fakir mutants display normal current-evoked synaptic communication at the neuromuscular junction but have attenuated touch-evoked activation of motor neurons. NMDA-evoked fictive swimming is not affected by the loss of CaV2.1b, suggesting that this channel is not required for motor pattern generation. These results, coupled with the expression of CACNA1Ab by sensory neurons, suggest that CaV2.1b channel activity is necessary for touch-evoked activation of the locomotor network in zebrafish.
authors.affiliation: Départment de Pathologie et Biologie Cellulaire, Groupe de Recherche sur le Système Nerveux Central et Centre d'Excellence en Neuromique de l'Université de Montéral, Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Sean E
authors.initials: SE
authors.lastname: Low
authors.forename: Ian G
authors.initials: IG
authors.lastname: Woods
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lachance
authors.forename: Joel
authors.initials: J
authors.lastname: Ryan
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Schier
authors.forename: Louis
authors.initials: L
authors.lastname: Saint-Amant
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D002038:Bungarotoxins / Q000378:metabolism; D020864:Calcium Channels, N-Type / Q000235:genetics / Q000378:metabolism*; D003472:Curare / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian; D004924:Escape Reaction / Q000187:drug effects / Q000502:physiology; D005071:Evoked Potentials / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000235:genetics*; D007930:Leucine / Q000235:genetics; D008124:Locomotion / Q000187:drug effects / Q000235:genetics; D008958:Models, Molecular; D009025:Morpholines / Q000494:pharmacology; D009043:Motor Activity / Q000235:genetics; D009046:Motor Neurons / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D016297:Mutagenesis, Site-Directed / Q000379:methods; D009154:Mutation / Q000235:genetics; D020125:Mutation, Missense / Q000235:genetics; D009415:Nerve Net / Q000502:physiology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000235:genetics; D014110:Touch / Q000235:genetics* / Q000502:physiology; D014633:Valine / Q000235:genetics; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D002038:Bungarotoxins; D020864:Calcium Channels, N-Type; D009025:Morpholines; D018733:Nicotinic Antagonists; D029961:Zebrafish Proteins; D003472:Curare; C037574:morpholine; D007930:Leucine; D014633:Valine; D000109:Acetylcholine