The Role of Nitric Oxide in Hyperaemic Response to Flicker in the Retina and Optic Nerve in Cats

Acta Ophthalmol Scand. 1997 Jun;75(3):232-5. doi: 10.1111/j.1600-0420.1997.tb00762.x.

Abstract

Purpose: To elucidate the role of nitric oxide (NO) in the eye and the flicker-induced vascular response.

Methods: The blood flow in the retina and different parts of the optic nerve was compared in cats treated with the NO-synthase blocker, N(G)-nitro-L-arginine methyl ester and in control animals. In both groups, one of the eyes was dark-adapted, the other was subjected to 8 Hz flickering light. The regional blood flow was measured with the microsphere method.

Results: In control animals, flickering light increased blood flow in the retina and optic nerve head by 39% and 256%, respectively. Pretreatment with N(G)-nitro-L-arginine methyl ester prevented this increase in retinal blood flow and markedly reduced the blood flow in the optic nerve heads.

Conclusion: NO release may mediate much of the vasodilating effect of flicker in cats, and play a role in maintaining normal vascular tone in the optic nerve head.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Blood Flow Velocity / radiation effects
  • Cats
  • Dark Adaptation / physiology
  • Enzyme Inhibitors / pharmacology
  • Hyperemia / etiology
  • Hyperemia / physiopathology*
  • Light*
  • Microspheres
  • Nitric Oxide / physiology*
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitroarginine / pharmacology
  • Optic Disk / blood supply
  • Optic Nerve / blood supply
  • Optic Nerve / drug effects
  • Optic Nerve / physiology*
  • Optic Nerve / radiation effects
  • Photic Stimulation
  • Regional Blood Flow
  • Retina / drug effects
  • Retina / physiology*
  • Retina / radiation effects
  • Retinal Vessels / drug effects
  • Retinal Vessels / physiology
  • Retinal Vessels / radiation effects
  • Vasodilation / drug effects
  • Vasodilation / radiation effects

Substances

  • Enzyme Inhibitors
  • Nitroarginine
  • Nitric Oxide
  • Nitric Oxide Synthase