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Professor Malin Malmsjö, MD, PhD. Photo.

Malin Malmsjö

Professor

Professor Malin Malmsjö, MD, PhD. Photo.

Enhanced acetylcholine and P2Y-receptor stimulated vascular EDHF-dilatation in congestive heart failure

Author

  • Malin Malmsjö
  • Anders Bergdahl
  • X H Zhao
  • X Y Sun
  • T Hedner
  • Lars Edvinsson
  • David Erlinge

Summary, in English

OBJECTIVE: Congestive heart failure (CHF) is accompanied by impaired peripheral blood flow and endothelial dysfunction with decreased release of nitric oxide (NO). Strong evidence supports the existence of another vasodilatory substance, endothelium derived hyperpolarising factor (EDHF), which has not previously been studied in CHF. METHOD: CHF was induced by left coronary artery ligation resulting in a reproducible myocardial infarction in Sprague Dawley rats. Vasodilatory responses to acetylcholine and extracellular nucleotides (ATP, ADP beta S, ADP and UTP) were examined in cylindrical segments of the mesenteric artery, precontracted with noradrenaline. The combined NO- and EDHF-dilatation (after inhibition of cyclo-oxygenase pathways) was called "total dilatation", as indomethacin had only minor effects in this system. NO-dilatation was studied in segments pretreated with indomethacin and the potassium channel inhibitors charybdotoxin (10(-7.5) M) and apamin (10(-6) M), while EDHF-dilatations were studied in the presence of indomethacin (10(-5) M) and L-NOARG (10(-3.5) M). RESULTS: EDHF-dilatations in CHF were strongly up-regulated for ACh (36% vs. 73%; sham vs. CHF operated rats), ADP beta S (10% vs. 42%), ADP (0% vs. 21%) and UTP (3% vs. 35%). These dilatations were abolished by a combination of charybdotoxin and apamin, confirming that they were mediated by EDHF. The NO-dilatations on the other hand were down-regulated in CHF as compared to sham operated rats for ACh (93% vs. 76%; sham vs. CHF operated rats), ADP beta S (61% vs. 37%). ADP (60% vs. 30%), ATP (49% vs. 34%) and UTP (65% vs. 47%), while a minor decrease was seen in the total dilatation for ACh (87% vs. 75%; sham vs. CHF operated rats), ADP beta S (47% vs. 42%), ADP (59% vs. 39%), ATP (52% vs. 39%) and UTP (59% vs. 44%). CONCLUSION: In this model of non-atherosclerotic CHF there was a minor decrease in the total dilatation and a marked down-regulation of the NO-mediated dilatation, while the EDHF-dilatation was up-regulated. Increased EDHF-activity in CHF may represent a compensatory response to decreased NO-activity to preserve endothelial function and tissue perfusion.

Department/s

  • Medicine, Lund
  • Cardiology

Publishing year

1999

Language

English

Pages

200-209

Publication/Series

Cardiovascular Research

Volume

43

Issue

1

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Cardiac and Cardiovascular Systems

Keywords

  • Regional bloodflow
  • Nitric oxide
  • Heart failure
  • Adenosine
  • Endothelial function

Status

Published

ISBN/ISSN/Other

  • ISSN: 1755-3245