Effects of dietary L-arginine on the reactivity of canine coronary arteries

Edward C. Ray, Michael E. Landis, Virginia M. Miller

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Experiments were designed to determine the effects of supplemental dietary L-arginine on the endothelial and smooth muscle function of canine coronary arteries. One group of dogs was fed the standard laboratory chow while another group was supplemented with 250 mg/kg per day L-arginine. All dogs had undergone bilateral reversed interposition saphenous vein grafting and received 325 mg/day oral aspirin. After 5 weeks of arginine feeding, left circumflex coronary arteries were removed, cut into rings, and suspended for the measurement of isometric force in organ chambers. Concentration-response curves were obtained to L-arginine, UK-14,304 (α2-adrenergic agonist) and A23187 (calcium ionophore) in the absence and presence of N(G)-monomethyl-L- arginine (L-NMMA) and tetraethylammonium (TEA) alone or in combination. Serum concentrations of L-arginine increased by about 20% following 2 weeks of arginine feeding and remained elevated throughout the study. In rings with and without endothelium contracted with prostaglandin F(2α), L-arginine caused concentration-dependent contractions in rings from control animals but no significant change in tension in rings from arginine-fed animals. Contractions to L-arginine in control animals were reduced by either L-NMMA or TEA. Endothelium-dependent relaxations to the α2-adrenergic agonist were decreased with arginine feeding while relaxations to the calcium ionophore and the endothelium-derived factor nitric oxide were similar among groups. Relaxations to UK-14,304 were reduced by L-NMMA in both groups but by TEA only in rings from control animals. These results suggest that dietary supplementation with L-arginine modifies reactivity of endothelium and smooth muscle by at least two mechanisms: one associated with activation of potassium channels and the other with receptor-coupled release of nitric oxide.

Original languageEnglish (US)
Pages (from-to)211-217
Number of pages7
JournalVascular Medicine
Volume4
Issue number4
DOIs
StatePublished - 1999

Keywords

  • Arginase
  • Endothelium
  • Endothelium-derived factors
  • L-NMMA
  • Monomethyl-L- arginine
  • Nitric oxide
  • Nitric oxide synthase
  • Smooth muscle

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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