The presence of an alpha-adrenoceptor--mediated coronary vasoconstrictor reflex during acute systemic hypoxia was examined in thirteen chloralose-anesthetized dogs. Local vasodilator effects were avoided by perfusing the left common coronary artery (LCC) with normoxic blood, while the dogs were ventilated with 5% 02-95% N2 . Left ventricular afterload was held constant and positive cardiac inotropic responses and beta two-adrenoceptor-mediated coronary vasodilation were blocked by propranolol. Parasympatheticmediated bradycardia and coronary vasodilation were blocked with atropine. Systemic hypoxia decreased LCC flow to normoxic myocardium by 19.4+2.6 %. Although myocardial oxygen extraction increased 9.7+2.9 %, myocardial oxygen consumption decreased 16.5+2.6 %. Intracoronary prazosin prevented the reflex vasoconstriction during repeated hypoxia.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc501191 |
| Date | 12 1900 |
| Creators | Grice, Derald Preston |
| Contributors | Downey, H. Fred, Jones, Carl E., Quist, Eugene, Jacobson, Myron |
| Publisher | North Texas State University |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | ix, 107 leaves: ill., Text |
| Rights | Public, Grice, Derald Preston, Copyright, Copyright is held by the author, unless otherwise noted. All rights reserved. |
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