TY - JOUR
T1 - TEP on the tide in killifish (Fundulus heteroclitus)
T2 - Effects of progressively changing salinity and prior acclimation to intermediate or cycling salinity
AU - Wood, Chris M.
AU - Grosell, Martin
N1 - Funding Information:
Acknowledgments We thank Sue Ebanks and Bob Gerdes for excellent maintenance of the aquatic system, and two anonymous reviewers whose constructive comments improved the MS. The experiments complied with the current laws of the United States and Canada. The research was supported by NSF grants (0416440, 0714024 and 0743903) to MG and an NSERC Discovery Grant to CMW. CMW is supported by the Canada Research Chair Program.
PY - 2009/5
Y1 - 2009/5
N2 - Transepithelial potentials (TEP) were measured in killifish, acclimated to freshwater (FW), seawater (SW), 33% SW or cycling salinities relevant to tidal cycles in an estuary, and subsequently subjected to salinity changes in progressive or random order. Random compared to progressive salinity changes in an upward or downward direction in FW- and SW-acclimated fish, respectively, did not greatly influence responses to salinity change. Fish acclimated to SW or 33% SW as well as those acclimated to cycling salinities behaved similarly (TEP more positive than +15 mV in 100% SW, decreasing to ∼0 mV at 20-40% SW, and more negative than -30 mV in FW). In contrast, FW-acclimated fish displayed a less pronounced TEP response to salinity (0 mV in FW through 20% SW, increasing thereafter to values more positive than +10 mV at 100% SW). We conclude that when evaluated under estuarine tidal conditions, the killifish gill exhibits adaptive electrical characteristics, opposing Na+ loss at low salinity and favouring Na+ extrusion at high salinity, changes explained at least in part by the Cl- to Na+ permeability ratio. Thus animals living in the estuaries can move to lower and higher salinities for short periods with little physiological disturbance, but this ability is lost after acclimation to FW.
AB - Transepithelial potentials (TEP) were measured in killifish, acclimated to freshwater (FW), seawater (SW), 33% SW or cycling salinities relevant to tidal cycles in an estuary, and subsequently subjected to salinity changes in progressive or random order. Random compared to progressive salinity changes in an upward or downward direction in FW- and SW-acclimated fish, respectively, did not greatly influence responses to salinity change. Fish acclimated to SW or 33% SW as well as those acclimated to cycling salinities behaved similarly (TEP more positive than +15 mV in 100% SW, decreasing to ∼0 mV at 20-40% SW, and more negative than -30 mV in FW). In contrast, FW-acclimated fish displayed a less pronounced TEP response to salinity (0 mV in FW through 20% SW, increasing thereafter to values more positive than +10 mV at 100% SW). We conclude that when evaluated under estuarine tidal conditions, the killifish gill exhibits adaptive electrical characteristics, opposing Na+ loss at low salinity and favouring Na+ extrusion at high salinity, changes explained at least in part by the Cl- to Na+ permeability ratio. Thus animals living in the estuaries can move to lower and higher salinities for short periods with little physiological disturbance, but this ability is lost after acclimation to FW.
KW - Diffusion potential
KW - Electrogenic potential
KW - Estuaries
KW - Gill permeability
KW - P/P ratio
KW - Salinity
KW - Tidal cycle
KW - Transepithelial potential
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U2 - 10.1007/s00360-008-0323-3
DO - 10.1007/s00360-008-0323-3
M3 - Article
C2 - 19115061
AN - SCOPUS:65249090166
VL - 179
SP - 459
EP - 467
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
SN - 0174-1578
IS - 4
ER -