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Studies of Cardiac Muscle with a High Permeability to Calcium Produced by Treatment with Ethylenediaminetetraacetic Acid
| Content Provider | Semantic Scholar |
|---|---|
| Author | Winegard, Saul |
| Copyright Year | 1971 |
| Abstract | Thin strips of frog ventricle were isolated and bathed for 15 min in a solution containing 140 mM KCl, 5 mM Na(2)ATP, 3 mM EDTA, and 10 mM Tris buffer at pH 7.0. The muscle was then exposed to contracture solutions containing 140 mM KCl, 5 mM Na(2)ATP, 1 mM MgCl(2), 10 mM Tris, 3 mM EGTA, and CaCl(2) in amounts to produce concentrations of free calcium from 10(-4.8)M to 10(-9)M. The muscles developed some tension at approximately 10(-8)M, and maximum tension was achieved in 10(-5)M Ca(++). They relaxed in Ca(++) concentrations less than 10(-8)M. The development of tension by the EDTA-treated muscles was normalized by comparison with twitch tension at a stimulation rate of 9 per min before exposure to EDTA. In 10(-5)M Ca(++) tension was always several times the twitch tension and was greater than the contracture tension of a frog ventricular strip in KCl low Na-Ringer. Tension equal to half-maximum was produced at approximately 10(-6.2)M Ca(++). Intracellular recording of membrane potential indicated that after EDTA treatment the resting potential of cells in Ringer solution with 10(-5)M Ca or less was between 5 and 20 mv. Contracture solutions did not produce tension without prior treatment with EDTA. The high permeability of the membrane produced by EDTA was reversed and the normal resting and action potentials restored in 1 mM Ca-Ringer. Similar studies of EDTA-treated rabbit right ventricular papillary muscle produced a similar tension vs. Ca(++) concentration relation, and the high permeability state reversed with exposure to normal Krebs solution. |
| Starting Page | 71 |
| Ending Page | 93 |
| Page Count | 23 |
| File Format | PDF HTM / HTML |
| PubMed reference number | 4998356v1 |
| Volume Number | 58 |
| Journal | The Journal of general physiology |
| Alternate Webpage(s) | http://jgp.rupress.org/content/jgp/58/1/71.full.pdf |
| Alternate Webpage(s) | https://www.st-va.ncbi.nlm.nih.gov/pmc/articles/PMC2226010/pdf/71.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Action Potentials Anura Artificial cardiac pacemaker Bathing Buffers Calcium Chloride Calcium ion Contracture Edetic Acid Egtazic Acid Heart Ventricle Membrane Potentials Myocardium Potassium Chloride Relaxation Rest Sodium Solutions Structure of papillary muscle Tension Tetany Tissue membrane Tromethamine strip medical device |
| Content Type | Text |
| Resource Type | Article |
