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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1975-11-1
pubmed:abstractText
The purpose of this study was to determine the relative effects of acute hypoxemia on constrictor responses to norepinephrine and angiotensin in two vascular beds, the coronary and skeletal muscle. The left circumflex coronary and gracilis muscle arteries of anesthetized dogs were perfused at constant flow. Practolol or propranolol was administered to block indirect myocardial effects of norepinephrine on coronary resistance. When Po2 of arterial blood perfusing the coronary and muscle beds was reduced from 101 to 44 mm while systemic Pco2 remained normal, constrictor responses to both norepinephrine and angiotensin were inhibited in coronary vessels but not in muscle vessels. When local Po2 was reduced to 27 mm Hg, inhibition of responses was again observed in the coronary circulation with both drugs; in the muscle, responses to angiotensin but not to norepinephrine were depressed significantly. Since intracoronary infusion of adenosine increased, rather than inhibited, vasoconstrictor responses to angiotensin, it is unlikely that release of adenosine during hypoxemia accounts for inhibition of vasoconstriction in the coronary circulation. Indomethacin did not alter the inhibition of coronary vasoconstrictor responses to angiotensin during hypoxemia, which suggests that releease of prostglandins during htpoxemia is not the primary mechanism for inhibition of coronary vascular responses. When contractions in the gracilis muscle were produced by electrical stimulation, vasconstrictor responses to norepinnephrine were inhibited during hypoxemia. We conclude that depression of constrictor responses by hypoxemia is more pronounced in the coronay circulation than in resting muscle, but when muscle is contracting, vasoconstrictor responses are impaired during hypoxemia.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
193
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
941-50
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Effect of hypoxemia on responses to norepinephrine and angiotensin in coronary and muscular vessels.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.