title: Electrical aspects of the osmorespiratory compromise: TEP responses to hypoxia in the euryhaline killifish (Fundulus heteroclitus) in freshwater and seawater.
abstract: The osmorespiratory compromise, the trade-off between the requirements for respiratory and ionoregulatory homeostasis at the gills, becomes more intense during environmental hypoxia. One aspect that has been previously overlooked is possible change in transepithelial potential (TEP) caused by hypoxia, which will influence branchial ionic fluxes. Using the euryhaline killifish, we show that acute hypoxia reduces the TEP across the gills by approximately 10 mV in animals acclimated to both freshwater (FW) and seawater (SW), with a higher PO2  threshold in the former. TEP becomes negative in FW, and less positive in SW. The effects are immediate, stable for at least 3 h, and reverse immediately upon return to normoxia. Hypoxia also blocks the normal increase in TEP that occurs upon transfer from FW to SW, but does not reduce the fall in TEP that occurs with transfer in the opposite direction. These effects may be beneficial in FW but not in SW.
authors.affiliation: Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL 33149, USA Department of Zoology, University of British Columbia, 4200 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4 Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, Canada L8S 4K1 woodcm@zoology.ubc.ca.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Wood
authors.affiliation: Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL 33149, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Grosell
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D005618:Fresh Water; D023781:Fundulidae / Q000502:physiology*; D005880:Gills / Q000502:physiology*; D008564:Membrane Potentials; D064587:Osmoregulation; D010100:Oxygen / Q000378:metabolism; D054712:Salinity; D012623:Seawater
chemical_list: D010100:Oxygen
keywords: Diffusion potential; Electrogenic potential; Gill permeability; PCl/PNa ratio; Transepithelial potential