Document Detail

Ca(2+)-induced inhibition of sodium pump: effects on energetic metabolism of mouse diaphragm tissue.
MedLine Citation:
PMID:  9834848     Owner:  NLM     Status:  MEDLINE    
Tissues of mouse diaphragms were incubated in Liley solution containing 2, 4, 6 and 10 mmol/l calcium. When diaphragm tissue was incubated in 10 mmol/l calcium, an increase of intracellular calcium concentration from 314 +/- 28 to 637 +/- 26 nmol/l was estimated by fluorescent Ca2+ indicator Fura-2/AM. Moreover, incubation of the tissue in 10 mmol/l Ca2+ led to complete inhibition of electrogenic activity of the sodium pump, as measured by intracellular microelectrodes in a single muscle cell. This inhibition was fully reversible after 5 min washing with Liley solution containing 2 mmol/l CaCl2. The Ca(2+)-induced blocking effect on electrogenic activity of the sodium pump was accompanied by inhibition of glucose incorporation into the muscle tissue. Calcium at concentrations of 6 and 10 mmol/l in bath medium significantly inhibited both CO2 production and O2 consumption. A continual decrease of respiration (CO2/O2) quotient was observed under increasing concentrations of calcium. Moreover, an exponential decrease of ATP tissue levels was observed at increasing concentrations of calcium in the bath medium. On the other hand, massive acceleration of anaerobic glycolysis induced by incubation of the tissue in a medium containing high calcium concentration is improbable. This may be deduced from the fact that only about an 50% increase of lactate content in muscle tissue was observed when diaphragms were incubated for 30 min in medium containing calcium ions at 6 and 10 mmol/l as compared with the control tissue incubated for the same time in the medium containing 2 mmol/l CaCl2. In conclusion it could be stressed that increase of Ca2+ concentration in bath medium induced in diaphragm muscle tissue an elevation of intracellular Ca2+ concentration accompanied by a depression of sodium pump electrogenic activity and a depression of energy metabolism. These changes may be involved in pathology of muscle tissue during the Ca2+ overload.
Z Sulová; F Vyskocil; T Stankovicová; A Breier
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  General physiology and biophysics     Volume:  17     ISSN:  0231-5882     ISO Abbreviation:  Gen. Physiol. Biophys.     Publication Date:  1998 Sep 
Date Detail:
Created Date:  1999-02-19     Completed Date:  1999-02-19     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8400604     Medline TA:  Gen Physiol Biophys     Country:  SLOVAKIA    
Other Details:
Languages:  eng     Pagination:  271-83     Citation Subset:  IM    
Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia.
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MeSH Terms
Calcium / physiology*
Calcium Chloride / pharmacology*
Energy Metabolism* / drug effects
Muscle, Skeletal / drug effects,  metabolism*
Sarcolemma / drug effects,  physiology
Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors*
Reg. No./Substance:
10043-52-4/Calcium Chloride; 7440-70-2/Calcium; EC ATPase

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