Distribution of cardiac output during induced isometric exercise in dogs

S. C. Crayton, R. Aung-Din, David E Fixler, Jere H Mitchell

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Abstract

Studies were designed to characterize the distribution of cardiac output during induced isometric exercise in anesthetized dogs. The response to isometric exercise involved significant increases in heart rate (+12 ± 3%(SE)), mean arterial pressure (+13 ± 2%), cardiac output (+26 ± 8%), and respiratory minute volume (+75 ± 26%); total peripheral resistance did not change significantly. Significant changes in blood flow were observed during isometric exercise in kidneys (-18 ± 6%) and contracting limb muscles (+453 ± 154%). Flow to liver (hepatic artery), spleen, brain, and myocardium remained near control values. Section of spinal dorsal roots L6-L7 abolished the responses to isometric exercise except for the increase in flow to exercising limb muscles. Alpha-adrenergic receptor blockade abolished the decrease in renal blood flow during isometric exercise; however, the increase in flow to exercising limb muscles was not affected by either alpha- or beta-adrenergic blockade.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume5
Issue number2
Publication statusPublished - 1979

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ASJC Scopus subject areas

  • Physiology

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