| Low-sodium contractures indicating sarcolemmal Na/Ca-exchange in the frog heart. | |
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MedLine Citation:
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PMID: 2904338 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. In the frog heart, Ca2+ enters the cell by the slow inward current (Isi) and by an electrogenic, carrier-mediated, and passive Na-out/Ca-in-exchange. 2. The latter reverses to Na-in/Ca-out-exchange during depolarization and thereby controls relaxation. 3. The exchange ratio is 3 Na+ for 1 Ca2+. 4. The Na/Ca-exchange is not inhibited by organic Ca-antagonists in frog myocardium, indicating that the initiation of the heart beat may mainly depend on Isi. 5. This is not necessarily in contradiction with the Na-Ca-antagonism, since there also exists an antagonism between Na+ and Ca2+ in the slow channel. 6. However, the contractures caused by a decrease of NaO+ are mediated by the Na/Ca-exchange. |
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Authors:
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R Volkmann |
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Publication Detail:
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Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Review |
Journal Detail:
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Title: Comparative biochemistry and physiology. A, Comparative physiology Volume: 91 ISSN: 0300-9629 ISO Abbreviation: Comp Biochem Physiol A Comp Physiol Publication Date: 1988 |
Date Detail:
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Created Date: 1989-01-26 Completed Date: 1989-01-26 Revised Date: 2008-10-30 |
Medline Journal Info:
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Nlm Unique ID: 1276312 Medline TA: Comp Biochem Physiol A Comp Physiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 225-34 Citation Subset: IM |
Affiliation:
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Department of Clinical Physiology, University of Göteborg, Sweden. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Calcium / metabolism Ion Exchange Myocardial Contraction / drug effects Myocardium / metabolism* Ranidae Sarcolemma / metabolism Sodium / metabolism*, pharmacology |
| Chemical | |
Reg. No./Substance:
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7440-23-5/Sodium; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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