Role of nitric oxide during the initial phase of reperfusion after retinal ischemia in the rat.
The onset of reperfusion and the recovery of the ERG b-wave following retinal ischemia was examined among three groups of rats: group 1 (n = 12) and group 2 (n = 6) received pretreatment with NG-nitro-L-arginine (20 mg/kg, i.p., 2 h before ischemia) followed by intravenous injection of saline (group 1) or of 200 mg/kg L-arginine (group 2) 5 min before the end of ischemia; group 3 (n = 7) received saline pretreatment followed by intravenous injection of saline as a control. Group 1 showed delayed onset of reperfusion compared to the other two groups and a reduction in the rate of the b-wave recovery compared to the control on the 1st day after reperfusion (group 1 vs. group 3; p = 0.0357). The L-arginine posttreatment significantly increased the b-wave recovery (group 2 vs. group 1; p = 0.0005 on day 1 and p < 0.0006 on day 3). The rate of the b-wave recovery in group 1 was inversely proportional to the time to establish complete reperfusion. Inhibition of nitric oxide synthase during the initial phase of reperfusion may worsen the recovery of the b-wave following retinal ischemia, at least in part, by inhibiting establishment of reperfusion.
Hangai
M
M
Department of Ophthalmology and Visual Science, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Yoshimura
N
N
Hiroi
K
K
Mandai
M
M
Honda
Y
Y
D000818:Animals; D004195:Disease Models, Animal; D004596:Electroretinography / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007511:Ischemia / Q000188:drug therapy / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D012164:Retinal Diseases / Q000188:drug therapy / Q000201:enzymology / Q000503:physiopathology*; D012171:Retinal Vessels / Q000187:drug effects / Q000201:enzymology / Q000503:physiopathology*; D016896:Treatment Outcome
D004791:Enzyme Inhibitors; D019335:Nitroarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester