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Endothelium-dependent relaxations in canine coronary arteries are enhanced in early heart failure and persist in recovery.

Authors
  • Larosa, G
  • Armstrong, P W
  • Forster, C
Type
Published Article
Journal
Canadian journal of physiology and pharmacology
Publication Date
Oct 01, 1994
Volume
72
Issue
10
Pages
1148–1154
Identifiers
PMID: 7882178
Source
Medline
License
Unknown

Abstract

In vitro coronary artery responsiveness to noradrenaline, phenylephrine, and BHT-920 together with functional relaxation to acetylcholine was assessed in dogs at the early onset of pacing-induced heart failure (1 week) and in dogs recovered from heart failure (3 weeks paced, followed by 4 weeks discontinued pacing). alpha-Adrenoceptor stimulation produced contractile responses that were unaltered in early congestive heart failure and recovery. Contractions to noradrenaline and BHT-920 were always less than those produced by phenylephrine. Endothelium-intact arteries demonstrated relaxations in response to noradrenaline and BHT-920, but not phenylephrine. Relaxations to noradrenaline were enhanced 24% in early heart failure and 47% following recovery from heart failure, compared with control. BHT-920 produced relaxations that were augmented 21 and 76% in early heart failure and recovery, respectively. Contractile sensitivity to noradrenaline increased 5-fold in early heart failure and was not different in recovery, compared with control. Contractile sensitivity to BHT-920 and phenylephrine was unaltered throughout. Acetylcholine produced relaxations that were increased 21% in early heart failure and 13% after recovery from congestive heart failure. Furthermore, acetylcholine sensitivity was significantly enhanced in early heart failure and recovery. The current study reveals a progressive adaptation of the coronary endothelium in congestive heart failure, possibly directed towards protection against excessive vasoconstriction due to circulating catecholamines.

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