| High extracellular K+ during hypoxic preconditioning episodes attenuates the post-ischemic contractile and ionic benefits of preconditioning. | |
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MedLine Citation:
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PMID: 10072728 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Hypoxic preconditioning improves contractile recovery and decreases calcium loading following ischemia and reperfusion. To test whether changing the trans-sarcolemmal K+ gradient during the preconditioning period changes preconditioning's benefits, isolated rat hearts were subjected to two, 5 min hypoxic intervals in the presence of normal K+ (5mM, NmlK-PC) or high K+ (10.3 mM, HiK-PC), separated by 5 min of normoxic reflow. Preconditioning with 5 mM K+ significantly improved developed pressure (DP) after 30 min of ischemia as compared to non-preconditioned control hearts (55.9+/-4.41% v 12.4+/-2.01% of baseline, P<0.05). DP recovery was diminished with 10.3 mM K+ (25.1+/-4.20% of baseline, P<0.05). At the end of reperfusion, cell Ca2+ trended lower in hypoxic preconditioned hearts compared with control hearts (12.9+/-1.9 v 19.4+/-2.6 micromol/g dry wt, P=0.09) and was significantly lower than high K+ hearts (22.9+/-1.4 micromol/g dry wt, P<0.006). Intracellular K+ during reperfusion was significantly higher in preconditioned compared with control hearts (P<0.02) and high K+ hearts (P<0.002) (231+/-10 v 166+/-17 v 155+/-14 micromol/g dry wt, respectively). Thus, the trans-sarcolemmal K+ gradient during the preconditioning period influences preconditioning effects; decreasing the gradient attenuates preconditioning's favorable influences on contractile recovery, cellular K+ loss, and calcium loading during reperfusion. |
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Authors:
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K M Baumgarten; G Gerstenblith; R G Weiss |
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Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: Journal of molecular and cellular cardiology Volume: 31 ISSN: 0022-2828 ISO Abbreviation: J. Mol. Cell. Cardiol. Publication Date: 1999 Jan |
Date Detail:
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Created Date: 1999-05-20 Completed Date: 1999-05-20 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0262322 Medline TA: J Mol Cell Cardiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 203-13 Citation Subset: IM |
Affiliation:
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The Johns Hopkins Hospital, Baltimore, MD 21205, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Anoxia / metabolism* Calcium / analysis Disease Models, Animal Dose-Response Relationship, Drug Edetic Acid / pharmacology Ischemia / metabolism Ischemic Preconditioning, Myocardial* Lidocaine / pharmacology Male Perfusion Potassium / metabolism*, pharmacology Rats Rats, Wistar Reperfusion Sarcolemma / chemistry Time Factors Ventricular Pressure / drug effects |
| Chemical | |
Reg. No./Substance:
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137-58-6/Lidocaine; 60-00-4/Edetic Acid; 7440-09-7/Potassium; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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