This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Ray, E. C Articles by Miller, V. M Search for Related Content PubMed PubMed Citation Articles by Ray, E. C Articles by Miller, V. M Social Bookmarking                         What's this?

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

Mayo Graduate School of Medicine, Mayo Foundation, Rochester, MN, USA, Department of Surgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642-8410, USA

Michael E Landis

Department of Surgery, Mayo Foundation, Rochester, MN, USA

Virginia M Miller

Department of Surgery Mayo Foundation, Rochester, MN, USA, Physiology and Biophysics, Mayo Foundation, Rochester, MN, USA

Experiments were designed to determine the effects of supplemental dietary l-argi-nine 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 (a₂-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_2a, 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 a₂-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.

Key Words: arginase • endothelium • endothelium-derived factors • l-NMMA • monomethyl-l-argi-nine • nitric oxide • nitric oxide synthase • smooth muscle

Vascular Medicine, Vol. 4, No. 4, 211-217 (1999)
DOI: 10.1177/1358836X9900400402


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?