Scientific article
English

Lactate-induced retinal arteriolar vasodilation implicates neuronal nitric oxide synthesis in minipigs

Published inInvestigative ophthalmology & visual science, vol. 49, no. 11, p. 5060-5066
Publication date2008
Abstract

PURPOSE: To investigate the role of neuronal nitric oxide (NO) synthesis in the retinal vasodilatory response to lactate in minipigs. METHODS: Thirteen eyes of 13 minipigs were evaluated. Ten eyes received an intravenous infusion of N(omega)-nitro-L-arginine methyl ester (L-NAME). After 1 hour, the same eyes received an intravitreous juxta-arteriolar microinjection of 30 microL of L-lactate 0.5 M (pH 7.4) through a micropipette. Ten minutes later, 9 of 10 eyes received an intravitreous juxta-arteriolar microinjection of 30 microL of L-NAME 0.01 M (pH 7.4), and 1 received physiologic saline solution (PSS). The remaining three eyes received a microinjection of 30 microL of L-lactate 0.5 M (pH 7.4), without intravenous or intravitreous L-NAME. RESULTS: The three eyes that received juxta-arteriolar injection of L-lactate only showed a reproducible increase in retinal arteriolar diameter that persisted during the entire study period (maximum effect at 20 minutes, 40.9% +/- 3.2%). Retinal arteriolar diameter decreased by 4.1% 1 hour after intravenous L-NAME when compared with baseline but the difference did not reach significance. The juxta-arteriolar injection of L-lactate induced a significant increase in retinal arteriolar diameter (22.7% and 28.7% at 5 and 10 minutes, respectively; P < 0.01), followed by a significant decrease (8.6%; P < 0.01) 10 minutes after juxta-arteriolar injection of L-NAME. Injection of PSS had no effect on retinal arteriolar diameter. CONCLUSIONS: Juxta-arteriolar administration of L-lactate induced vasodilation, which was also observed with continuous intravenous infusion of L-NAME. Moreover, juxta-arteriolar L-NAME microinjection significantly suppressed the vasodilatory effect of L-lactate. These data suggest that neuronal-derived NO is an important mediator of lactate-induced vasodilation in minipigs.

Keywords
  • Animals
  • Arterioles/cytology/drug effects/physiology
  • Blood Pressure/physiology
  • Dose-Response Relationship, Drug
  • Endothelium, Vascular/cytology/metabolism
  • Enzyme Inhibitors/administration & dosage
  • Infusions, Intravenous
  • Microinjections
  • NG-Nitroarginine Methyl Ester/administration & dosage
  • Nitric Oxide/biosynthesis
  • Retinal Artery/cytology/drug effects/physiology
  • Swine
  • Swine, Miniature
  • Vasodilation/drug effects
  • Vitreous Body
Affiliation entities Not a UNIGE publication
Citation (ISO format)
MENDRINOS, Efstratios et al. Lactate-induced retinal arteriolar vasodilation implicates neuronal nitric oxide synthesis in minipigs. In: Investigative ophthalmology & visual science, 2008, vol. 49, n° 11, p. 5060–5066. doi: 10.1167/iovs.08-2087
Main files (1)
Article (Accepted version)
accessLevelRestricted
Identifiers
Journal ISSN0146-0404
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