| Effects of hypertension on cardiovascular responses to epinephrine in humans. | |
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MedLine Citation:
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PMID: 17307999 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Cardiac beta-receptor responsiveness is diminished by both aging and hypertension. However, concomitant decreases in the activity of counterregulatory mechanisms, such as the arterial baroreflex and neuronal catecholamine uptake, influence the ultimate cardiac responses to adrenergic agents in vivo. In the present study, we evaluated by echocardiography cardiac responses to intravenous infusion of epinephrine in 14 young and 18 older normotensive men and women and in 10 young and 17 older hypertensive men and women. To assess the relative contribution of intrinsic cardiac and counterregulatory components to the overall response, infusions were repeated combined with a ganglionic blocker in the young groups. Epinephrine-induced increases in heart rate were similar in the four groups. Increases in stroke volume, ejection fraction, and cardiac index were similar in the two hypertensive and two young normotensive groups. In contrast, they were attenuated in the older normotensive group, resulting in higher left ventricular responses in older hypertensive than in normotensive subjects. Heart rate and left ventricular responses to epinephrine in the presence of ganglionic blockade did not differ between the two young groups. Increases in plasma norepinephrine due to epinephrine infusion were larger in hypertensive than in normotensive subjects. One may conclude that compared with young normotensive subjects, in hypertensive subjects mechanisms increasing versus decreasing cardiac responses to epinephrine may remain in balance, and, compared with older normotensive subjects, older hypertensive subjects exhibit enhanced cardiac responses to sympathetic stimulation. |
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Authors:
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Frans H H Leenen; Anne Fourney; Elizabeth Coletta; Roselyn White |
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Publication Detail:
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Type: Clinical Trial; Comparative Study; Journal Article; Research Support, Non-U.S. Gov't Date: 2007-02-16 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 292 ISSN: 0363-6135 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2007 Jun |
Date Detail:
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Created Date: 2007-06-12 Completed Date: 2007-08-02 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H3025-31 Citation Subset: IM |
Affiliation:
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Hypertension Unit, University of Ottawa Heart Institute, H360, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada. fleenen@ottawaheart.ca |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic beta-Agonists
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administration & dosage*,
blood Adult Age Factors Aged Aging* Baroreflex / drug effects Blood Pressure / drug effects* Dose-Response Relationship, Drug Epinephrine / administration & dosage*, blood Female Ganglionic Blockers / administration & dosage Heart Rate / drug effects* Humans Hypertension / blood, physiopathology*, ultrasonography Infusions, Intravenous Male Middle Aged Norepinephrine / blood Stroke Volume / drug effects Sympathetic Nervous System / drug effects*, physiopathology Trimethaphan / administration & dosage Vascular Resistance / drug effects Ventricular Function, Left / drug effects* |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic beta-Agonists; 0/Ganglionic Blockers; 51-41-2/Norepinephrine; 51-43-4/Epinephrine; 7187-66-8/Trimethaphan |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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