title: Distribution of cardiac output during induced isometric exercise in dogs.
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.
mesh_terms: D000818:Animals; D002302:Cardiac Output; D003714:Denervation; D004285:Dogs; D004558:Electric Stimulation; D005727:Ganglia, Spinal / Q000502:physiology*; D007537:Isometric Contraction; D008863:Microspheres; D009132:Muscles / Q000502:physiology; D005082:Physical Exertion; D011868:Radioisotopes
chemical_list: D011868:Radioisotopes