| The influence of intracellular lactate and H+ on cell volume in amphibian skeletal muscle. | |
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MedLine Citation:
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PMID: 16613877 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The combined effects of intracellular lactate and proton accumulation on cell volume, Vc, were investigated in resting Rana temporaria striated muscle fibres. Intracellular lactate and H+ concentrations were simultaneously increased by exposing resting muscle fibres to extracellular solutions that contained 20-80 mm sodium lactate. Cellular H+ and lactate entry was confirmed using pH-sensitive electrodes and 1H-NMR, respectively, and effects on Vc were measured using confocal microscope xz-scanning. Exposure to extracellular lactate up to 80 mm produced significant changes in pH and intracellular lactate (from a pH of 7.24 +/- 0.03, n = 8, and 4.65 +/- 1.07 mm, n = 6, respectively, in control fibres, to 6.59 +/- 0.03, n = 4, and 26.41 +/- 0.92 mm, n = 3, respectively) that were comparable to those observed following fatiguing stimulation (6.30-6.70 and 18.04 +/- 1.78 mm, n = 6, respectively). Yet, the increase in intracellular osmolarity expected from such an increase in intracellular lactate did not significantly alter Vc. Simulation of these experimental results, modified from the charge difference model of Fraser & Huang, demonstrated that such experimental manoeuvres produced changes in intracellular [H+] and [lactate] comparable to those observed during muscle fatigue, and accounted for this paradoxical conservation of Vc through balancing negative osmotic effects resulting from the net cation efflux that would follow a titration of intracellular membrane-impermeant anions by the intracellular accumulation of protons. It demonstrated that with established physiological values for intracellular buffering capacity and the permeability ratio of lactic acid and anionic lactate, P(LacH): P(Lac-), this would provide a mechanism that precisely balanced any effect on cell volume resulting from lactate accumulation during exercise. |
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Authors:
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Juliet A Usher-Smith; James A Fraser; Peter S J Bailey; Julian L Griffin; Christopher L-H Huang |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2006-04-13 |
Journal Detail:
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Title: The Journal of physiology Volume: 573 ISSN: 0022-3751 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 2006 Jun |
Date Detail:
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Created Date: 2006-06-15 Completed Date: 2006-08-18 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: England |
Other Details:
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Languages: eng Pagination: 799-818 Citation Subset: IM |
Affiliation:
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Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK. jau20@cam.ac.uk |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cell Size* Hydrogen-Ion Concentration Intracellular Fluid / chemistry*, metabolism Membrane Potentials Microscopy, Confocal Models, Biological Muscle Fatigue / physiology Muscle Fibers, Skeletal / chemistry, cytology*, metabolism, physiology Muscle, Skeletal / chemistry, cytology*, metabolism, physiology Protons* Rana temporaria Sodium Lactate / metabolism* Time Factors |
| Grant Support | |
ID/Acronym/Agency:
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//Wellcome Trust |
| Chemical | |
Reg. No./Substance:
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0/Protons; 72-17-3/Sodium Lactate |
| Comments/Corrections | |
Comment In:
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J Physiol. 2007 Jul 1;582(Pt 1):461-5; author reply 467-70
[PMID:
17446216
]
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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