| Interactive effects of K+, acid, norepinephrine, and ischemia on the heart: implications for exercise. | |
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MedLine Citation:
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PMID: 9104837 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We tested the hypothesis that cardiac ischemia uncouples the beneficial interaction among hyperkalemia, acidosis, and raised plasma catecholamines when these chemicals are changed to mimic their exercise levels. Potassium chloride, lactic acid, and norepinephrine (NE) were infused intravenously for 2 min into anesthetized, artificially ventilated, thoracotomized rabbits during either occlusion of the left circumflex artery (3 min; n = 10) or after a period of prolonged ischemia (20 min; n = 7) that led to a small infarction. NE (1 microg x kg(-1) x min(-1) iv) offset the negative cardiac effects of hyperkalemia (up to 8.7 +/- 0.7 mM) and acidosis (arterial pH 7.09 +/- 0.03) in normal hearts. Cardiac performance was not significantly depressed by either acute or chronic ischemia before any infusions. However, the protective effect of NE during acute ischemia or after prolonged ischemia with hyperkalemia and acidosis was substantially reduced. These results show that cardiac ischemia attenuates the protective action of NE and increases the depressive effects of hyperkalemia and acidosis. Whether myocardial ischemia amplifies the cardiotoxic effects of hyperkalemia and acidosis during vigorous exercise by attenuating the beneficial effect of catecholamines remains to be determined. |
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Authors:
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M O'Neill; C E Sears; D J Paterson |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 82 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1997 Apr |
Date Detail:
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Created Date: 1997-06-26 Completed Date: 1997-06-26 Revised Date: 2010-08-25 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1046-52 Citation Subset: IM |
Affiliation:
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University Laboratory of Physiology, Oxford, United Kingdom. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acidosis
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physiopathology* Adrenergic alpha-Agonists / pharmacology* Animals Blood Pressure / drug effects Female Heart / drug effects, physiology* Hydrogen-Ion Concentration Hyperkalemia / physiopathology Male Myocardial Ischemia / physiopathology* Norepinephrine / pharmacology* Physical Conditioning, Animal / physiology* Physical Exertion / physiology* Potassium / pharmacology* Rabbits Ventricular Function, Left / drug effects, physiology |
| Grant Support | |
ID/Acronym/Agency:
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//Wellcome Trust |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic alpha-Agonists; 51-41-2/Norepinephrine; 7440-09-7/Potassium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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