Electrical aspects of the osmorespiratory compromise: TEP responses to hypoxia in the euryhaline killifish (<i>Fundulus heteroclitus</i>) in fresh water and sea water

Wood, Chris M.; Grosell, Martin

doi:10.1242/jeb.122176

Cited by 9 publications

(4 citation statements)

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“…during normoxia)? It may be because they cause other unfavourable effects, such as reductions in nitrogenous waste excretion, as seen in the oscar in freshwater (Wood et al, 2007(Wood et al, , 2009, and changes in transepithelial potential, which have been documented in the killifish in both freshwater and seawater (Wood and Grosell, 2015). Potentially, they may also interfere with the ability to acid-base regulate, though to our knowledge, this has not been tested.…”

Section: The Overall Responses In Net Water Balancementioning

confidence: 97%

The osmorespiratory compromise in the euryhaline killifish: water regulation during hypoxia

Wood

Ruhr

Schauer

et al. 2019

Journal of Experimental Biology

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Freshwater-and seawater-acclimated Fundulus heteroclitus were exposed to acute hypoxia (10% air saturation, 3 h), followed by normoxic recovery (3 h). In both salinities, ventilation increased and heart rate fell in the classic manner, while _ M O 2 initially declined by ∼50%, with partial restoration by 3 h of hypoxia, and no O 2 debt repayment during recovery. Gill paracellular permeability (measured with [ 14 C] PEG-4000) was 1.4-fold higher in seawater, and declined by 50% during hypoxia with post-exposure overshoot to 188%. A similar pattern with smaller changes occurred in freshwater. Drinking rate (also measured with [ 14 C] PEG-4000) was 8-fold higher in seawater fish, but declined by ∼90% during hypoxia in both groups, with post-exposure overshoots to ∼270%. Gill diffusive water flux (measured with 3 H 2 O) was 1.9-fold higher in freshwater fish, and exhibited a ∼35% decrease during hypoxia, which persisted throughout recovery, but was unchanged during hypoxia in seawater fish. Nevertheless, freshwater killifish gained mass while seawater fish lost mass during hypoxia, and these changes were not corrected during normoxic recovery. We conclude that this hypoxiatolerant teleost beneficially reduces gill water permeability in a salinity-dependent fashion during hypoxia, despite attempting to simultaneously improve _ M O 2 , but nevertheless incurs a net water balance penalty in both freshwater and seawater.

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Section: The Overall Responses In Net Water Balancementioning

confidence: 97%

The osmorespiratory compromise in the euryhaline killifish: water regulation during hypoxia

Wood

Ruhr

Schauer

et al. 2019

Journal of Experimental Biology

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“…There are a number of publications showing that adaptation to hypoxia at the cellular level is regulated by decreasing energy consuming processes (Boutilier, 2001). Hypoxia reduced the TEP by 10 mV in seawater-and freshwater-acclimated killifish Fundulus heteroclitus and reversed immediately after return to normoxia (Wood and Grossel, 2015). In the freshwater fish Astronotus ocellatus Na + K + -ATPase activity was decreased and subsequently Na + uptake capacity reduced as a response to acute hypoxa.…”

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confidence: 89%

The effects of hypoxia on active ionic transport processes in the gill epithelium of hyperregulating crab, Carcinus maneas

Lucu

Ziegler

2017

Comparative Biochemistry and Physiology Part A: Molecular &

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A B S T R A C TEffects of hypoxia on the osmorespiratory functions of the posterior gills of the shore crab Carcinus maenas acclimated to 12 ppt seawater (DSW) were studied. Short-circuit current (Isc) across the hemilamella (one epithelium layer supported by cuticle) was substantially reduced under exposure to 1.6, 2.0, or 2.5 mg O 2 /L hypoxic saline (both sides of epithelium) and fully recovered after reoxygenation. Isc was reduced equally in the epithelium exposed to 1.6 mg O 2 /L on both sides and when the apical side was oxygenated and the basolateral side solely exposed to hypoxia. Under 1.6 mg O 2 /L, at the level of maximum inhibition of Isc, conductance was decreased from 40.0 mS cm − 2 to 34.7 mS cm − 2 and fully recovered after reoxygenation. Isc inhibition under hypoxia and reduced 86 Rb + (K + ) fluxes across apically located K + channels were caused preferentially by reversible inhibition of basolaterally located and ouabain sensitive Na + ,K + -ATPase mediated electrogenic transport. Reversible inhibition of Isc is discussed as decline in active transport energy supply down regulating metabolic processes and saving energy during oxygen deprivation. In response to a 4 day exposure of Carcinus to 2.0 mg O 2 /L, hemolymph Na + and Cl − concentration decreased, i.e. hyperosmoregulation was weakened. Variations of the oxygen concentration level and exposure time to hypoxia lead to an increase of the surface of mitochondria per epithelium area and might in part compensate for the decrease in oxygen availability under hypoxic conditions.

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“…Consistent with previous findings by Voyles et al (2009), infected L. caerulea during the intermoult period had lower transcutaneous electrophysiological parameters (TEP, amiloride-sensitive I SC , skin resistance) and lower levels of plasma Na + and Cl − than uninfected frogs. Small changes in the electrical properties of an epithelia can have large consequences for the maintenance of physiological homeostasis (Wood and Grosell, 2008); for example, a −10 mV change in the TEP is correlated with a reduction in plasma [Na + ] by 33.5% in killifish (Wood and Grosell, 2015). The combination of reduced TEP, reduced active uptake and increased skin permeability could explain the low plasma Na + (hyponatremia) and Cl − (hypochloremia) levels seen in infected L. caerulea.…”

Section: Physiological Disruption Of the Skinmentioning

confidence: 99%

Epidermal epidemic: unravelling the pathogenesis of chytridiomycosis

Cramp

Ohmer

et al. 2018

Journal of Experimental Biology

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Chytridiomycosis, a lethal fungal skin disease of amphibians, fatally disrupts ionic and osmotic homeostasis. Infected amphibians increase their skin shedding rate (sloughing) to slow pathogen growth, but the sloughing process also increases skin permeability. Healthy amphibians increase active ion uptake during sloughing by increasing ion transporter abundance to offset the increased skin permeability. How chytridiomycosis affects the skin function during and between sloughing events remains unknown. Here, we show that non-sloughing frogs with chytridiomycosis have impaired cutaneous sodium uptake, in part because they have fewer sodium transporters in their skin. Interestingly, sloughing was associated with a transient increase in sodium transporter activity and abundance, suggesting that the newly exposed skin layer is initially fully functional until the recolonization of the skin by the fungus again impedes cutaneous function. However, the temporary restoration of skin function during sloughing does not restore ionic homeostasis, and the underlying loss of ion uptake capacity is ultimately detrimental for amphibians with chytridiomycosis.

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Electrical aspects of the osmorespiratory compromise: TEP responses to hypoxia in the euryhaline killifish (Fundulus heteroclitus) in fresh water and sea water

Cited by 9 publications

References 11 publications

The osmorespiratory compromise in the euryhaline killifish: water regulation during hypoxia

The osmorespiratory compromise in the euryhaline killifish: water regulation during hypoxia

The effects of hypoxia on active ionic transport processes in the gill epithelium of hyperregulating crab, Carcinus maneas

Epidermal epidemic: unravelling the pathogenesis of chytridiomycosis

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