| CaMKII is responsible for activity-dependent acceleration of relaxation in rat ventricular myocytes. | |
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MedLine Citation:
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PMID: 7864197 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We investigated the role of Ca/calmodulin-dependent protein kinase (CaMKII) in relaxation and cytosolic free [Ca] ([Ca]i) decline during steady-state (SS) and postrest (PR) twitches in intact rat ventricular myocytes. Half-time of mechanical relaxation and time constant of [Ca]i decline (tau) were twofold greater during PR than with SS at 1 Hz. This difference was 1) abolished by inhibition of sarcoplasmic reticulum (SR) Ca accumulation by thapsigargin or caffeine; 2) greater at higher stimulation frequency and extracellular [Ca], which affected only SS tau; 3) abolished by the protein phosphatase inhibitor okadaic acid (10 microM, which selectively accelerated [Ca]i decline during PR); 4) still present during stimulation or inhibition of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (PKA) by 10 microM forskolin or 1 microM H-89, respectively (SS and PR tau values were abbreviated and prolonged, respectively); and 5) suppressed by 10 microM KN-62, a selective inhibitor of CaMKII, which selectively prolonged [Ca]i decline during SS twitches. Both protein kinase inhibitors were also shown to decrease the SR Ca-uptake rate in digitonin-permeabilized rat myocytes. We conclude that CaMKII plays a major role in modulation of relaxation in rat ventricular myocytes, enhancing SR Ca uptake in a activity-dependent fashion. Our results are also compatible with a background, activity-independent stimulation of SR Ca uptake by PKA in intact rat myocytes. |
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Authors:
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R A Bassani; A Mattiazzi; D M Bers |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 268 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1995 Feb |
Date Detail:
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Created Date: 1995-03-20 Completed Date: 1995-03-20 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: H703-12 Citation Subset: IM |
Affiliation:
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Department of Physiology, Loyola University School of Medicine, Maywood, Illinois 60153. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Calcium / metabolism Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors, physiology* Electric Stimulation Intracellular Membranes / metabolism Male Myocardial Contraction / physiology* Myocardium / cytology Osmolar Concentration Rats Rats, Sprague-Dawley Rest Sarcoplasmic Reticulum / metabolism Stimulation, Chemical Ventricular Function / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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HL-30077/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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7440-70-2/Calcium; EC 2.7.11.17/Calcium-Calmodulin-Dependent Protein Kinases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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