Cutaneous Ion Transport in the Freshwater Teleost Synbranchus marmoratus

Stiffler, Daniel F.; Graham, John L.; Dickson, Kathryn A.; Stöckmann, Wieland

doi:10.1086/physzool.59.4.30158594

Cited by 29 publications

(7 citation statements)

References 15 publications

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“…Although some investigations have suggested that cutaneous ionic fluxes take place in emersed fish with limited water contact (Eddy et al. 1980; Stiffler et al. 1986; Fenwick and Lam 1988) there does not, as yet, appear to be any direct evidence to suggest that amphibious fish can prevent desiccation physiologically.…”

Section: Fluid and Thermal Balancementioning

confidence: 99%

Adaptations of amphibious fish for surviving life out of water

2005

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There are a small number of fish species, both marine and freshwater, that exhibit a truly amphibious habit that includes periods of aerial exposure. The duration of emersion is reflected in the level of physical and physiological adaptation to an amphibious lifestyle. Fish that are only briefly out of water retain predominantly aquatic attributes whereas there are semi‐terrestrial species that are highly adapted to prolonged periods in the aerial habitat. Desiccation is the main stressor for amphibious fish and it cannot be prevented by physiological means. Instead, amphibious fish resist excessive water loss by means of cutaneous modification and behavioural response. The more terrestrially adapted fish species can tolerate considerable water loss and may employ evaporation to aid thermoregulation. The amphibious habit is limited to fish species that can respire aerially. Aerial respiration is usually achieved through modification to existing aquatic pathways. Freshwater air‐breathers may respire via the skin or gills but some also have specialized branchial diverticula. Marine species utilize a range of adaptations that may include modified gills, specialized buccopharyngeal epithelia, the intestine and the skin. Areas of enhanced respiratory activity are typified by increased vascularization that permits enhanced perfusion during aerial exposure. As with other adaptations the mode of nitrogenous elimination is related to the typical durations of emersion experienced by the fish. Intertidal species exposed on a regular cycle, and which may retain some contact with water, tend to remain ammoniotelic while reducing excretion rates in order to prevent excessive water loss. Amphibious fish that inhabit environments where emersion is less predictable than the intertidal, can store nitrogen during the state of emersion with some conversion to ureotelism or have been shown to tolerate high ammonia levels in the blood. Finally, the more amphibious fish are more adapted to moving on land and seeing in air. Structural modifications to the pectoral, pelvic, dorsal and anal fins, combined with a well‐developed musculature permit effective support and movement on land. For vision in air, there is a general trend for fish to possess close‐set, moveable, protruberant eyes set high on the head with various physical adaptations to the structure of the eye to allow for accurate vision in both air and water.

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Section: Fluid and Thermal Balancementioning

confidence: 99%

Adaptations of amphibious fish for surviving life out of water

2005

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“…Influx and efflux rates are probably back in balance, but the internal body Na pool has been reset to a higher or lower level. When Synbranchus marmoratus (∼1‰) and P. schlosseri (∼8‰) were emersed, Na ϩ (influx and efflux) and Ca 2ϩ (influx), respectively, continued to move through the skin (Stiffler et al 1986;Fenwick and Lam 1988). It is unlikely that the kidney was involved in Na ϩ efflux in SW fish to any great extent because mostly divalent ions and few monovalent ions are released in urine (Marshall and Grosell 2006).…”

Section: Role Of Skin Versus Gill Under Terrestrial Conditionsmentioning

confidence: 99%

“…In this species, the cutaneous surface appears to be important in gas exchange (Ong et al 2007) and NH 3 excretion (Frick and Wright 2002b;Litwiller et al 2006). The FW swamp eel (Synbranchus marmoratus) also endures long periods of emersion in a damp environment and continues to take up ions (albeit at low rates) from the environment through the cutaneous surface (Stiffler et al 1986). Similarly, in the marble goby (Oxyeleotris marmorata) and the mudskipper (Periophthalmodon schlosseri), Ca 2ϩ influx (but not efflux) continued at low rates through the cutaneous surface when the fish were placed in air on wet filter paper saturated with seawater (SW; Fenwick and Lam 1988).…”

Section: Introductionmentioning

confidence: 99%

A Fish Out of Water: Gill and Skin Remodeling Promotes Osmo- and Ionoregulation in the Mangrove KillifishKryptolebias marmoratus

LeBlanc

Wood

Fudge

et al. 2010

Physiological and Biochemical Zoology

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The euryhaline, amphibious mangrove killifish Kryptolebias marmoratus is known to survive weeks out of water in moist environments. We tested the hypothesis that the skin is a site of osmo- and ionoregulation in K. marmoratus. We predicted that under terrestrial conditions, gill and skin remodeling would result in an enhanced role for skin and a diminished role for the gills in osmo- and ionoregulation. Fish were exposed to water-either freshwater (FW, 1‰) or hypersaline water (saltwater [SW], 45‰)-or air over a moist surface of FW or SW for 9 d and then recovered in water. When fish were emersed for 9 d, (22)Na and (3)H-H(2)O were exchanged across the cutaneous surface. Homeostasis of whole-body Cl(-) and water levels but not of Na(+) levels was maintained over 9 d in air. In air-exposed fish, there was a significant increase in the size of skin ionocytes (in SW), a decrease in the number of skin mucous cells (in SW), and an increase in the gill interlamellar cell mass relative to those of fish in water. Gill ionocytes were mostly embedded away from the external surface in air-exposed fish, but the number and size of ionocytes increased (in FW). Interestingly, skin ionocytes formed distinct clusters of 20-30 cells. The estimated number of ionocytes over the whole skin surface was comparable to that in the gills. Overall, the findings support the hypothesis that the skin is a site of osmo- and ionoregulation in K. marmoratus in aquatic and terrestrial environments. Reversible cellular and morphological changes to the skin and gills during air exposure probably enhanced the cutaneous contribution to ion and water balance.

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“…In the postembryonic stages, CC localization varies among species and, in some cases, according to milieu. Oncorhynchus kisutch (Salmonidae; Richman et al, 1987), lower jaw skin of Gillichthys mirabilis (Gobiidae; Marshall, 1977) and in the whole skin of Blennius pholis (Blenniidae; Nonnotte et al, 1979) and Synbranchus marmoratus (Synbranchidae: Stiffler et al, 1986). CCs have also been found in the pseudobranch (Laurent and Dunel-Erb, 1984), opercular membrane (the epithelial lining on the inside of the operculum) of Fundulus heteroclitus (Cyprinodontidae; Karnaky and Kinter, 1977), Fundulus grandis (Cyprinodontidae; Krasny and Zadunaisky, 1978), Oreochromis mossarnbicus (Foskett et al, 1981).…”

Section: Chloride Cell Distribution and Morphologymentioning

confidence: 99%