Sodium- potassium-activated adenosine triphosphatase and osmotic regulation by fishes

Lm, Jampol; Fh, Epstein

doi:10.1152/ajplegacy.1970.218.2.607

Cited by 155 publications

(35 citation statements)

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“…It has long been recognized that intestinal Na + absorption is ultimately fueled by Na + /K + -ATPase (referred to as NKA in the following), as is the case for most other absorptive epithelia (Jampol and Epstein, 1970;Colin et al, 1985). The NKA is localized to the basolateral membrane, although the columnar nature of the enterocytes dictates that the majority of the NKA protein resides in the lateral membrane, pumping Na + into the lateral interspace (lis) (Fig.…”

Section: Na + Absorption By the Marine Teleost Intestinementioning

confidence: 99%

“…1). The intestinal epithelium exhibits the highest NKA activity of the three teleost osmoregulatory tissues (gill, kidney and intestine) (Hogstrand et al, 1999;, an activity that in many cases is higher in seawateracclimated euryhaline fish than in freshwater-acclimated conspecifics (Fuentes et al, 1997;Colin et al, 1985;Jampol and Epstein, 1970;Kelly et al, 1999;Madsen et al, 1994). The electrogenic nature of NKA contributes to a strong cytosolic negative membrane potential and a low cytosolic Na + concentration in the order of 15 mmol l -1 (Zuidema et al, 1986).…”

Section: Na + Absorption By the Marine Teleost Intestinementioning

confidence: 99%

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High rates of HCO3– secretion and Cl– absorption against adverse gradients in the marine teleost intestine: the involvement of an electrogenic anion exchanger and H+-pump metabolon?

Grosell

Mager

Williams

et al. 2009

Journal of Experimental Biology

112

113

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Section: Na + Absorption By the Marine Teleost Intestinementioning

confidence: 99%

Section: Na + Absorption By the Marine Teleost Intestinementioning

confidence: 99%

High rates of HCO3– secretion and Cl– absorption against adverse gradients in the marine teleost intestine: the involvement of an electrogenic anion exchanger and H+-pump metabolon?

Grosell

Mager

Williams

et al. 2009

Journal of Experimental Biology

112

113

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“…The Na + absorption is ultimately fueled by the basolateral Na + /K + -ATPase (NKA), which extrudes 3Na + in exchange for 2K + and thereby establishes a strong cytosolic negative membrane potential and low intracellular Na + concentrations (Skou, 1990;Skou and Esmann, 1992) (Fig.·1). The NKA activity is generally high in marine fish intestine, even when compared to the gill Hogstrand et al, 1999), and is higher in euryhaline fish acclimated to seawater than in freshwater acclimated individuals (Colin et al, 1985;Fuentes et al, 1997;Jampol and Epstein, 1970;Kelly et al, 1999;Madsen et al, 1994), illustrating the osmoregulatory importance of this enzyme. Furthermore, NKA gene M. Grosell expression is elevated in the intestine of euryhaline teleost fish following transfer from freshwater to seawater, demonstrating the significance of this enzyme for successful marine osmoregulation (Cutler et al, 2000;Jensen et al, 1998;Seidelin et al, 2000).…”

Section: Intestinal Transport Processesmentioning

confidence: 99%

Intestinal anion exchange in marine fish osmoregulation

Grosell

2006

Journal of Experimental Biology

230

211

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Osmoregulation in marine fishThree distinct strategies for maintaining salt and water balance have evolved in fishes inhabiting the marine environments. (1) Osmoconformity/ionoconformity is found in the strictly marine agnathan hagfishes, which do not appear to regulate osmotic pressure and concentrations of main osmolytes to a great extent in seawater (Morris, 1958). (2) Osmoconformity and ionoregulation are seen in marine elasmobranchs (Hazon et al., 2003) and in the lobe-finned coelacanth (Griffith et al., 1974), which maintains plasma osmolality at or slightly above that of the surrounding seawater but NaCl concentrations at approximately d of ambient levels. (3) The most common strategy is osmoregulation, found in all teleosts (Marshall and Grosell, 2005) and marine lampreys (Morris, 1958), achieved by the regulation of the main extracellular electrolyte (Na + and Cl -) levels at approximately d of full strength seawater. Under steady state conditions at constant salinities, hagfish, elasmobranchs and coelacanths presumably do not need to drink to maintain water balance. It was shown, however, that the unavoidable renal and extra-renal fluid loss to the hypertonic marine environment in hypo-osmoregulating fish was compensated for by ingestion of seawater with subsequent water absorption across the gastro-intestinal tract (Smith, 1930). More recently, it was demonstrated that even the osmoconforming elasmobranchs display transient drinking when exposed to elevated ambient salinity, and evidence for components of the rennin-angiotensin system (RAS), even in the elasmobranchs (Anderson et al., 2002;Hazon et al., 2003) and hagfish (Cobb et al., 2004) as well as in lamprey (Brown et al., 2005), continues to accumulate. The drinking reflex is at least in part controlled by RAS and it thus appears that the ability to regulate ingestion of seawater and thereby the magnitude of intestinal fluid absorption is an ancestral osmoregulatory trait among fishes.The ingestion and processing of the imbibed seawater for osmoregulatory purposes have, at least in teleost fish, received much attention for three quarters of a century since the first classic studies by Smith published in 1930(Smith, 1930. It is now well established that an initial desalinization of the ingested seawater occurs in the esophagus, which absorbs Na + and Cl -through both passive and active transport pathways, Despite early reports, dating back three quarters of a century, of high total CO 2 concentrations in the intestinal fluids of marine teleost fishes, only the past decade has provided some insight into the functional significance of this phenomenon. It is now being recognized that intestinal anion exchange is responsible for high luminal HCO 3 -and CO 3 2-concentrations while at the same time contributing substantially to intestinal Cl -and thereby water absorption, which is vital for marine fish osmoregulation. In species examined to date, the majority of HCO 3 -secreted by the apical anion exchange process is derived from hydration of metabolic ...

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“…The enzyme is present in branchial tissue and usually increases in specific activity during seawater acclimation (Jampol andEpstein, 1970, Maetz andBornancin, 1975).…”

Section: Marine Teleostsmentioning

confidence: 99%

Osmotic and Ionic Regulation by Freshwater and Marine Fishes

Evans

1980

Environmental Physiology of Fishes

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Sodium- potassium-activated adenosine triphosphatase and osmotic regulation by fishes

Cited by 155 publications

References 0 publications

High rates of HCO3– secretion and Cl– absorption against adverse gradients in the marine teleost intestine: the involvement of an electrogenic anion exchanger and H+-pump metabolon?

High rates of HCO3– secretion and Cl– absorption against adverse gradients in the marine teleost intestine: the involvement of an electrogenic anion exchanger and H+-pump metabolon?

Intestinal anion exchange in marine fish osmoregulation

Osmotic and Ionic Regulation by Freshwater and Marine Fishes

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