Intravenous Administration of L-Arginine Increases Retinal and Choroidal Blood Flow - 18/08/11
Résumé |
Purpose |
Nitric oxide (NO) is among the most important regulators of ocular perfusion. L-arginine, an amino acid, is the precursor of NO synthesis. The aim of the present study was to determine whether administration of L-arginine affects ocular blood flow.
Design |
L-arginine (1 g/min) or placebo was administered intravenously for 30 minutes in 12 healthy volunteers in a randomized, double-masked, two-way cross-over design.
Methods |
Ocular hemodynamics were measured before, in the last 10 minutes of the infusion period, as well as 30 minutes after cessation of the administration. Retinal vessel diameters were measured with a retinal vessel analyzer, red blood cell velocities with bidirectional laser Doppler velocimetry, and pulsatile choroidal blood flow was measured using laser interferometry.
Results |
L-arginine significantly decreased mean arterial pressure by −8 ± 5% and −6 ± 7% at the two time points (P < .01), respectively. Intravenous administration of L-arginine increased choroidal blood flow by +10 ± 6% and +12 ± 7%, respectively. Retinal venous diameters decreased by −2.5 ± 2.1% and −1.4 ± 2.7%, respectively, whereas red blood cell velocity significantly increased after administration of L-arginine by +22 ± 23% and +20 ± 19% at the two time points. Thus, calculated blood flow in retinal veins, increased by +21 ± 18% and +21 ± 19% before and after the end of L-arginine infusion.
Conclusions |
Intravenous administration of L-arginine increases retinal and choroidal blood flow in healthy volunteers. Whether this effect is related to an increased NO-production or an unidentified mechanism remains to be clarified. However, administration of L-arginine might be an interesting new approach to therapeutically increase ocular blood flow in ocular vascular disease.
Le texte complet de cet article est disponible en PDF.Plan
Vol 140 - N° 1
P. 69.e1-69.e9 - juillet 2005 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
L’accès au texte intégral de cet article nécessite un abonnement.
Déjà abonné à cette revue ?