Abstract |
Analyses of ashed muscle tissue show that the uptake of Ca(45) by isolated frog heart ventricles from normal Ringer's solution containing 1 mM Ca reaches a maximum value in about 30 minutes of perfusion which is not exceeded after 3 hours of perfusion. The average amount of this labeled Ca taken up from normal Ringer's is 0.7 mM/kg. wet weight of muscle. In contrast to this, the amount of labeled Ca taken up by ventricles perfused with K-free Ringer's increases at a linear rate over a 60 minute period to twice the normal value coinciding with the gradual development of contracture and coinciding with a cellular K loss and Na gain of about 30 mM/kg. How much of the extra labeled Ca taken up from K-free Ringer's represents a net gain in cellular Ca content is not known. However, evidence has been obtained that some of this labeled Ca enters an intracellular compartment. EDTA in K-free Ringer's solution causes relaxation of ventricles in contracture and also renders the muscle fibers indiscriminately permeable. This indicates that a combination of Ca with sensitive intracellular sites is probably the cause of the K lack contracture.
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Authors | L J THOMAS Jr |
Journal | The Journal of general physiology
(J Gen Physiol)
Vol. 43
Pg. 1193-206
(Jul 1960)
ISSN: 0022-1295 [Print] United States |
PMID | 13838003
(Publication Type: Journal Article)
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Chemical References |
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Topics |
- Calcium
(metabolism)
- Contracture
- Heart
(physiology)
- Heart Ventricles
- Muscles
- Myocardium
(metabolism)
- Perfusion
- Potassium
- Potassium Deficiency
- Sodium
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