1 The Body Compartments and the Distribution of Electrolytes

Holmes, W. N.; Donaldson, Edward M.

doi:10.1016/s1546-5098(08)60082-5

Cited by 178 publications

(139 citation statements)

References 142 publications

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“…The stingrays were held in a filtered, closed circulating, 15,000-liter holding tank. Fresh harbor water [28 o /oo (parts per thousand); ϳ850 mosmol/kgH2O] was pumped at high tide from Charleston Harbor to a settling tank from where it was then pumped to the holding tank. The salinity of the water in the holding tank was maintained at ϳ850 mosmol/kgH 2O.…”

Section: Animalsmentioning

confidence: 99%

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Effect of low environmental salinity on plasma composition and renal function of the Atlantic stingray, a euryhaline elasmobranch

Janech¹,

Fitzgibbon²,

Ploth³

et al. 2006

American Journal of Physiology-Renal Physiology

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. Effect of low environmental salinity on plasma composition and renal function of the Atlantic stingray, a euryhaline elasmobranch. Am J Physiol Renal Physiol 291: F770 -F780, 2006. First published April 11, 2006 doi:10.1152/ajprenal.00026.2006.-Marine elasmobranchs maintain internal osmolality higher than their external environment, resulting in an osmotic gradient for branchial water uptake. This gradient is markedly increased in low-salinity habitats. The subsequent increase in water uptake presents a challenge to volume homeostasis. The Atlantic stingray is a marine elasmobranch that inhabits a remarkable range of environmental salinities. We hypothesized that the ability of these stingrays to regulate fluid volume in low-salinity environments is due primarily to a renal glomerular and tubular functional reserve. We tested this hypothesis by measuring renal excretory function after a rapid and sustained 50% reduction in the osmolality of the external medium. Atlantic stingrays were maintained in harbor water [control salinity (CS) ϳ850 mosmol/kgH 2O] for 1 wk. Rays were then either transferred to diluted harbor water [low salinity (LS) ϳ440 mosmol/kgH 2O] or maintained in CS for a further 24 h. Renal excretory function was markedly higher in the rays subjected to low salinity. Glomerular filtration rate was threefold higher and urine flow rate ninefold higher in the LS group. The clearance of solute-free water was greater, and solute-free water comprised a significantly larger proportion of the urine output for the stingrays transferred to dilute harbor water. We conclude that 1) the kidneys of Atlantic stingrays have a remarkable glomerular and tubular functional reserve, and 2) the marked increase in renal function attenuates the increase in fluid volume when these fish move into low-salinity habitats. free water clearance; glomerular filtration rate; tubular urea reabsorption IN GENERAL, MARINE ELASMOBRANCH fishes (sharks, skates, and rays) maintain body fluids hyperosmotic to the ambient environment as part of their osmo-and volume-regulatory strategies. In the ocean, for example, plasma osmolality is 2-10% higher than the osmolality of the surrounding seawater (for review, see Ref. 28), this being due to their ability to maintain high Na ϩ , Cl Ϫ , and urea concentrations in the extracellular fluid (for review, see Refs. 28 and 51).Most species of marine elasmobranchs are confined to marine habitats (9) and only encounter relatively small variations in environmental salinity. However, some species are found in estuaries, as well as marine environments, and therefore can be considered marginally euryhaline (9). Furthermore, a small number of species are euryhaline; i.e., they are able to reside in marine, estuarine, riverine, and even freshwater habitats for extended periods of time. Although, these euryhaline elasmobranchs appear to migrate between habitats on a seasonal basis (48, 54), at least one species, the Atlantic stingray, Dasyatis sabina, can reproduce and complete its life cycle in freshwat...

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Section: Animalsmentioning

confidence: 99%

“…In the ocean, for example, plasma osmolality is 2-10% higher than the osmolality of the surrounding seawater (for review, see Ref. 28), this being due to their ability to maintain high Na ϩ , Cl Ϫ , and urea concentrations in the extracellular fluid (for review, see Refs. 28 and 51).…”

mentioning

confidence: 99%

Effect of low environmental salinity on plasma composition and renal function of the Atlantic stingray, a euryhaline elasmobranch

Janech¹,

Fitzgibbon²,

Ploth³

et al. 2006

American Journal of Physiology-Renal Physiology

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“…The colligative effect of the solutes in seawater (-0.45 M) depresses its freezing point to ca -l.g°C, whereas a typical teleost serum will freeze at ca -0.7OC (Holmes & Donaldson 1969). This discrepancy of ca 1°C in freezing points means that unprotected teleosts in polar and northern temperate waters would be at risk of freezing to death when their temperature fell below -0.7"C. Although there is evidence that some fish can survive at these temperatures in deep water in a supercooled state (DeVries 1980), this is not possible in shallow water or extremely cold, ice-laden deep water where contact with ice negates supercooling.…”

Section: Introductionmentioning

confidence: 99%

Antifreeze glycopeptides and peptides in Antarctic fish species from the Weddell Sea and the Lazarev Sea

Wöhrmann¹

1996

Mar. Ecol. Prog. Ser.

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Antifreeze glycopeptides and peptides have been isolated from 37 species of Antarctic fish representing the families Nototheniidae, Artedidraconidae, Bathydraconidae, Channichthyidae, Muraenolepididae. Liparididae, Zoarcidae and Myctophidae. Amino acid and carbohydrate analysis as well as antifreeze activity indicate that all investigated notothenioids contain antifreeze glycopeptides [AFGP). Pleuragramma antarcticurn, Lepidonotothen kempi, Bathydraco rnarri and Dolloidraco longedorsalis synthesize additional antifreeze molecules. The non-notothenioid species possess antifreeze peptides (AFP), except Muraenolepis marrnoratus and Macrourus holotrachys, which possess a glycosylated antifreeze pept~de similar to the AFGP found in the notothenio~d species. A novel glycopeptide comprised of the carbohydrate residue N-acetylglucosamine and the amino acids asparagine, glutamine, glycine, alanine, and traces of arginine, valine, leucine and threonine was isolated and characterized from P. antarcticum. The level of antifreeze concentration was dependent on the ambient water temperature, the depth of catch and life cycle of the species. Antifreeze activity of AFGP varies between 0.52 (Neopagetopsis ionah) and 1.20°C ( P antarctjcum) at a concentration of 20 mg ml-' Antifreeze activity of AFP is lower than 0.50°C. A linear increase in activity of the AFGP could be demonstrated concomitant with decreasing ice content. The structural diversity of antifreeze molecules and their occurrence in a wide range of Arctic and Antarctic fish species suggest that they evolved from precursor proteins before the continental drift and recently during Cenozoic glaciation into the various antifreeze molecules.

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“…15; see also 29,42). The high body fluid osmolality is achieved, in large part, by the retention of urea.…”

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confidence: 99%

Cloning and functional characterization of a second urea transporter from the kidney of the Atlantic stingray,Dasyatis sabina

Janech¹,

Fitzgibbon²,

Nowak³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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. Cloning and functional characterization of a second urea transporter from the kidney of the Atlantic stingray, Dasyatis sabina. Am J Physiol Regul Integr Comp Physiol 291: R844 -R853, 2006. First published April 13, 2006; doi:10.1152/ajpregu.00739.2005.-The cloning of cDNAs encoding facilitated urea transporters (UTs) from the kidneys of the elasmobranchs indicates that in these fish renal urea reabsorption occurs, at least in part, by passive processes. The previously described elasmobranch urea transporter clones from shark (shUT) and stingray (strUT-1) differ from each other primarily because of the COOHterminus of the predicted strUT-1 translation product being extended by 51-amino acid residues compared with shUT. Previously, we noted multiple UT transcripts were present in stingray kidney. We hypothesized that a COOH terminally abbreviated UT isoform, homologous to shUT, would also be present in stingray kidney. Therefore, we used 5Ј/3Ј rapid amplification of cDNA ends to identify a 3ЈUTR-variant (strUT-1a) of the cDNA that encodes (strUT-1), as well as three, 3ЈUTR-variant cDNAs (strUT-2a,b,c) that encode a second phloretinsensitive, urea transporter (strUT-2). The 5ЈUTR and the first 1,132 nucleotides of the predicted coding region of the strUT-2 cDNAs are identical to the strUT-1 cDNAs. The remainder of the coding region contains only five novel nucleotides. The strUT-2 cDNAs putatively encode a 379-amino acid protein, the first 377 amino acids identical to strUT-1 plus 2 additional amino acids. We conclude that 1) a second UT isoform is expressed in the Atlantic stingray and that this isoform is similar in size to the UT previously cloned from the kidney of the dogfish shark, and 2) at least five transcripts encoding the 2 stingray UTs are derived from a single gene product through alternative splicing and polyadenylation. elasmobranch; euryhaline; alternative splicing; osmoregulation MARINE ELASMOBRANCHS (sharks, skates, and rays) use a unique volume-and osmoregulatory strategy; in general, they maintain their body fluids hyperosmotic to the ambient environment (for a review, see Ref. 15; see also 29,42). The high body fluid osmolality is achieved, in large part, by the retention of urea. At ocean salinities, plasma urea concentrations average 350 mmol/l, and urea contributes 30 -50% of the plasma osmolality (for a review, see Ref. 15). The use of this strategy for body fluid volume regulation necessitates the efficient reabsorption of most of the filtered load of urea by the kidneys. For marine elasmobranchs maintained at ocean salinities, fractional urea reabsorption is 90 -98% (9, 14, 34).

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1 The Body Compartments and the Distribution of Electrolytes

Cited by 178 publications

References 142 publications

Effect of low environmental salinity on plasma composition and renal function of the Atlantic stingray, a euryhaline elasmobranch

Effect of low environmental salinity on plasma composition and renal function of the Atlantic stingray, a euryhaline elasmobranch

Antifreeze glycopeptides and peptides in Antarctic fish species from the Weddell Sea and the Lazarev Sea

Cloning and functional characterization of a second urea transporter from the kidney of the Atlantic stingray,Dasyatis sabina

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