Document Detail


Volumetric and ionic responses of goldfish hepatocytes to anisotonic exposure and energetic limitation.
MedLine Citation:
PMID:  12502772     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The relationship between cell volume and K(+) transmembrane fluxes of goldfish (Carassius auratus) hepatocytes exposed to anisotonic conditions or energetic limitation was studied and compared with the response of hepatocytes from trout (Oncorhynchus mykiss) and rat (Rattus rattus). Cell volume was studied by video- and fluorescence microscopy, while K(+) fluxes were assessed by measuring unidirectional (86)Rb(+) fluxes. In trout and rat hepatocytes, hyposmotic (180 mosmoll(-1)) exposure at pH 7.45 caused cell swelling followed by a regulatory volume decrease (RVD), a response reported to be mediated by net efflux of KCl and osmotically obliged water. By contrast, goldfish hepatocytes swelled but showed no RVD under these conditions. Although in goldfish hepatocytes a net ((86)Rb(+))K(+) efflux could be activated by N-ethylmaleimide, this flux was not, or only partially, activated by hyposmotic swelling (120-180 mosmoll(-1)). Blockage of glycolysis by iodoacetic acid (IAA) did not alter cell volume in goldfish hepatocytes, whereas in the presence of cyanide (CN(-)), an inhibitor of oxidative phosphorylation, or CN(-) plus IAA (CN(-)+IAA), cell volume decreased by 3-7%. Although in goldfish hepatocytes, energetic limitation had no effect on ((86)Rb(+))K(+) efflux, ((86)Rb(+))K(+) influx decreased by 57-66% in the presence of CN(-) and CN(-)+IAA but was not significantly altered by IAA alone. Intracellular K(+) loss after 20 min of exposure to CN(-) and CN(-)+IAA amounted to only 3% of the total intracellular K(+). Collectively, these observations suggest that goldfish hepatocytes, unlike hepatocytes of anoxia-intolerant species, avoid a decoupling of transmembrane K(+) fluxes in response to an osmotic challenge. This may underlie both the inability of swollen cells to undergo RVD but also the capability of anoxic cells to maintain intracellular K(+) concentrations that are almost unaltered, thereby prolonging cell survival.
Authors:
M V Espelt; P N Mut; G Amodeo; G Krumschnabel; P J Schwarzbaum
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  206     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2003 Feb 
Date Detail:
Created Date:  2002-12-27     Completed Date:  2003-10-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  513-22     Citation Subset:  IM    
Affiliation:
Instituto de Química y Fisicoquímica Biológicas (Facultad de Farmacia y Bioquímica), Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina.
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MeSH Terms
Descriptor/Qualifier:
Anaerobiosis
Animals
Biological Transport / physiology
Cell Size / drug effects,  physiology
Cyanides / pharmacology
Goldfish / physiology*
Hepatocytes / cytology,  drug effects,  metabolism*
Hydrogen-Ion Concentration
Hypertonic Solutions / pharmacology
Hypotonic Solutions / pharmacology
Iodoacetic Acid / pharmacology
Male
Microscopy, Fluorescence
Potassium / metabolism*
Potassium Chloride / pharmacology
Rats
Rats, Wistar
Rubidium Radioisotopes
Sodium / metabolism
Trout / physiology*
Water / physiology
Chemical
Reg. No./Substance:
0/Cyanides; 0/Hypertonic Solutions; 0/Hypotonic Solutions; 0/Rubidium Radioisotopes; 64-69-7/Iodoacetic Acid; 7440-09-7/Potassium; 7440-23-5/Sodium; 7447-40-7/Potassium Chloride; 7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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