title: The role of acid-sensing ion channels in epithelial Na+ uptake in adult zebrafish (Danio rerio).
abstract: Acid-sensing ion channels (ASICs) are epithelial Na(+) channels gated by external H(+). Recently, it has been demonstrated that ASICs play a role in Na(+) uptake in freshwater rainbow trout. Here, we investigate the potential involvement of ASICs in Na(+) transport in another freshwater fish species, the zebrafish (Danio rerio). Using molecular and histological techniques we found that asic genes and the ASIC4.2 protein are expressed in the gill of adult zebrafish. Immunohistochemistry revealed that mitochondrion-rich cells positive for ASIC4.2 do not co-localize with Na(+)/K(+)-ATPase-rich cells, but co-localize with cells expressing vacuolar-type H(+)-ATPase. Furthermore, pharmacological inhibitors of ASIC and Na(+)/H(+)-exchanger significantly reduced uptake of Na(+) in adult zebrafish exposed to low-Na(+) media, but did not cause the same response in individuals exposed to ultra-low-Na(+) water. Our results suggest that in adult zebrafish ASICs play a role in branchial Na(+) uptake in media with low Na(+) concentrations and that mechanisms used for Na(+) uptake by zebrafish may depend on the Na(+) concentration in the acclimation medium.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
authors.forename: Agnieszka K
authors.initials: AK
authors.lastname: Dymowska
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
authors.forename: David
authors.initials: D
authors.lastname: Boyle
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
authors.forename: Aaron G
authors.initials: AG
authors.lastname: Schultz
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 greg.goss@ualberta.ca.
authors.forename: Greg G
authors.initials: GG
authors.lastname: Goss
mesh_terms: D000064:Acclimatization; D062565:Acid Sensing Ion Channels / Q000235:genetics / Q000378:metabolism*; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D004848:Epithelium / Q000378:metabolism; D020869:Gene Expression Profiling; D005880:Gills / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism; D014867:Water / Q000737:chemistry; D015027:Zebrafish / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D062565:Acid Sensing Ion Channels; D007211:Indoles; D017923:Sodium-Hydrogen Exchangers; D029961:Zebrafish Proteins; D014867:Water; C007293:DAPI; D000584:Amiloride; D012964:Sodium; D025262:Vacuolar Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase; C039614:ethylisopropylamiloride
keywords: Acid-sensing ion channels; Gill; Ionoregulation; Sodium uptake; Zebrafish