Importance of basal nitric oxide synthesis in regulation of myocardial blood flow

Zoltán Benyó, Gergely Kiss, Csaba Szabo, Csilla Csáki, Arisztid G.B. Kovách

Research output: Contribution to journalReview article

50 Scopus citations

Abstract

Study objective - The aim was to investigate whether basal coronary vascular tone and myocardial perfusion depend upon endothelial nitric oxide (NO) synthesis.Design - Myocardial blood flow and vascular resistance of the left and right ventricles were studied before and after intravenous infusions of either NG-nitro-L-arginine (L-NA), a specific inhibitor of NO synthase, or L-arginine, the precursor of NO synthesis. Radiolabelled microspheres were used to study myocardial blood flow in small tissue sections.Experimental material - 14 anaesthetised male cats, weight 2.1-3.5 kg, were used.Measurements and main results - Measurements were made before and 15 and 40 min after L-NA treatment (30 mg·kg-1 bolus followed by 1 mg·kg-1·min-1 infusion; n=8), and before and 15 min after L-arginine treatment (30 mg·kg-1 bolus followed by 10 mg·kg-1·min-1 infusion; n=6). L-NA significantly reduced coronary blood flow to the left and right ventricle, by 30(SEM 9) and 48(6)% respectively, after 15 min, but only to the right ventricle, by 45(8)%, after 40 min. Mean arterial pressure and myocardial vascular resistance were raised during the L-NA infusion. In contrast, L-arginine did not elicit any change in the variables studied.Conclusions - The conductance of the coronary vascular bed and the resting myocardial blood flow is regulated by L-arginine derived nitric oxide, and exogenous L-arginine availability is not a limiting factor in this NO generation.

Original languageEnglish (US)
Pages (from-to)700-703
Number of pages4
JournalCardiovascular Research
Volume25
Issue number8
DOIs
StatePublished - Jan 1 1991
Externally publishedYes

Keywords

  • Blood pressure
  • Cat
  • Endothelium
  • In vivo
  • L-arginine
  • Myocardial blood flow
  • NG-nitro-L-arginine
  • Nitric oxide

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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