Publication Date:
1987-12-18
Description:
Recordings have been made of changes in intracellular calcium ion concentration ([Ca2+]i) that can be attributed to the operation of an electrogenic, voltage-dependent sodium-calcium (Na-Ca) exchanger in mammalian heart cells. Guinea pig ventricular myocytes under voltage clamp were perfused internally with fura-2, a fluorescent Ca2+-indicator, and changes in [Ca2+]i and membrane current that resulted from Na-Ca exchange were identified through the use of various organic channel blockers and impermeant ions. Depolarization of cells elicited slow increases in [Ca2+]i, with the maximum increase depending on internal [Na+], external [Ca2+], and membrane voltage. Repolarization was associated with net Ca2+ efflux and a decline in the inward current that developed instantaneously upon repolarization. The relation between [Ca2+]i and current was linear, and the slope was made steeper by hyperpolarization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Barcenas-Ruiz, L -- Beuckelmann, D J -- Wier, W G -- HL29473/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1987 Dec 18;238(4834):1720-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Maryland School of Medicine, Baltimore.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3686010" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Calcium/*metabolism
;
Carrier Proteins/*physiology
;
Cell Membrane/physiology
;
Guinea Pigs
;
Heart/*physiology
;
In Vitro Techniques
;
Kinetics
;
Membrane Potentials
;
Sodium-Calcium Exchanger
;
Ventricular Function
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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