| Freshwater Fish Gill Ion Transport: August Krogh to morpholinos and microprobes. | |
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MedLine Citation:
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PMID: 20874801 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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August Krogh proposed that freshwater fishes (and other freshwater animals) maintain body NaCl homoeostasis by extracting these ions from the environment via separate Na(+) /NH(4) (+) and Cl(-) /HCO(3) (-) exchangers in the gill epithelium. Subsequent data from other laboratories suggested that Na(+) uptake was more probably coupled to H(+) secretion via a vesicular proton pump (V-ATPase) electrically coupled to a Na(+) channel. However, despite uncertainty about electrochemical gradients, evidence has accrued that epithelial Na(+) /H(+) exchange indeed may be an alternative pathway for Na(+) uptake. The specific pathways for Na(+) uptake may be species and environment specific. An apical Cl(-) /HCO(3) (-) exchanger is generally accepted for most species (some species do not extract Cl(-) from freshwater), but the relative roles of anion exchanger-like (SLC4A1) vs. pendrin-like (SLC26Z4) exchangers are unknown, and also may be species specific. Most recently, data have supported the presence of an apical Na(+) + Cl(-) cotransporter (NCC-type), despite thermodynamic uncertainty. Ammonia extrusion may be via NH(3) diffusing through the paracellular junctions or NH(4) (+) substitution on both basolateral and apical ionic exchangers (Na(+) + K(+) -ATPase; Na(+) + K(+) + Cl(-) - cotransporter; and Na(+) /H(+) exchanger), but recent evidence suggests that Rhesus-glycoproteins mediate both basolateral and apical movement of ammonia. |
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Authors:
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D H Evans |
Publication Detail:
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Type: Journal Article Date: 2010-11-09 |
Journal Detail:
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Title: Acta physiologica (Oxford, England) Volume: 202 ISSN: 1748-1716 ISO Abbreviation: Acta Physiol (Oxf) Publication Date: 2011 Jul |
Date Detail:
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Created Date: 2011-06-14 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101262545 Medline TA: Acta Physiol (Oxf) Country: England |
Other Details:
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Languages: eng Pagination: 349-59 Citation Subset: IM |
Copyright Information:
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© 2010 The Author. Acta Physiologica © 2010 Scandinavian Physiological Society. |
Affiliation:
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Department of Biology, University of Florida, Gainesville, FL; and Mt Desert Island Biological Laboratory, Salisbury Cove, ME, USA. |
Export Citation:
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Descriptor/Qualifier:
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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