| Vasodilator reserve in respiratory muscles during maximal exertion in ponies. | |
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MedLine Citation:
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PMID: 3710976 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Eight healthy adult grade ponies were studied at rest as well as during maximal exertion carried out with and without adenosine infusion (3 microM X kg-1 X min-1 into the pulmonary artery) on a treadmill to compare levels of blood flow in respiratory muscles with those in other vigorously working muscles and to ascertain whether there remained any unutilized vasodilator reserve in respiratory muscles of maximally exercising ponies. Radionuclide-labeled 15-micron-diam microspheres, injected into the left ventricle, were used to study tissue blood flows. During maximal exertion, there were increases above base-line values in heart rate (336%), mean aortic pressure (41%), cardiac output (722%), and arterial O2 content (56%). The whole-body O2 consumption was 123 +/- 11 ml X min-1 X kg-1, and the stride/respiratory frequency of the galloping ponies was 138 +/- 4/min. With adenosine infusion during maximal exertion, mean aortic pressure decreased (P less than 0.05), but none of the above variables was different from maximal exercise alone. During maximal exertion, blood flow in the adrenal glands, myocardium, respiratory, and limb muscles increased, whereas that in the kidneys decreased and the cerebral perfusion remained unaltered. With adenosine infusion during maximal exercise, renal vasoconstriction intensified, whereas adrenal and coronary beds exhibited further vasodilatation. During maximal exertion, blood flow in the equine diaphragm (265 +/- 36 ml X min-1 X 100 g-1) was not different from that in the gluteus medius (253 +/- 36) and biceps femoris (233 +/- 29); both are principal muscles of propulsion in the equine subjects) or the triceps brachii (227 +/- 26) muscles.(ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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M Manohar |
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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: 60 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1986 May |
Date Detail:
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Created Date: 1986-07-08 Completed Date: 1986-07-08 Revised Date: 2008-11-21 |
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: 1571-7 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine
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pharmacology Animals Diaphragm / blood supply, physiology Female Hemodynamics Horses / physiology Intercostal Muscles / blood supply, physiology Male Muscle, Smooth / blood supply*, physiology Physical Exertion* Regional Blood Flow / drug effects Vascular Resistance / drug effects Vasodilation* Work of Breathing* |
| Chemical | |
Reg. No./Substance:
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58-61-7/Adenosine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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