[Nitric oxide donors and retinal vein occlusion].
OBJECTIVE
The development of extended territories of nonperfused capillaries after branch vein occlusion (b.v.o.) is correlated to the secondary constriction of the arteriole crossing the occluded territory. Local NO release is impaired soon after b.v.o. and accounts for the secondary arteriolar constriction. In this report we present evidences showing that administration of an NO donor can reverse the secondary arteriolar vasoconstriction observed after b.v.o.


METHODS
Simultaneous preretinal NO profiles and arteriolar diameter measurements were performed in miniature pigs after experimental b.v.o. The effect of preretinal microinjections of the NO-donor Sodium Nitroprusside on the arteriolar diameter was studied.


RESULTS
A significant arteriolar vasoconstriction occurring in parallel with a preretinal [NO] decrease was observed 4 hours after b.v.o. Microinjection of the NO-donor SNP caused a segmental, reversible arteriolar dilatation.


CONCLUSIONS
The present results, suggest that local NO supply in the first hours following b.v.o. may contribute to protect the retina against ischemic injury.
Donati
G
G
Clinique d'Ophtalmologie, Dpt. des Neurosciences cliniques, Genève.
Kapetanios
A D
AD
Pournaras
C J
CJ
D000818:Animals; D008845:Microinjections; D020030:Nitric Oxide Donors / Q000008:administration & dosage*; D009599:Nitroprusside / Q000008:administration & dosage*; D012039:Regional Blood Flow / Q000187:drug effects; D012161:Retinal Artery / Q000187:drug effects; D012169:Retinal Vein / Q000187:drug effects; D012170:Retinal Vein Occlusion / Q000188:drug therapy*; D013552:Swine; D013556:Swine, Miniature; D014655:Vascular Resistance
D020030:Nitric Oxide Donors; D009599:Nitroprusside
Donneurs de NO et occlusion veineuse rétinienne.