The effects of naloxone on retinal ischemia in rats.
The efficacy of naloxone (NL), a broad spectrum opioid antagonist, on retinal ischemia, was evaluated in a rat model of retinal ischemia with histopathologic and morphometric criteria. Two intraperitoneal injections of naloxone 3 mg/kg given immediately and 6 hr after reperfusion showed beneficial effects to the retina as evaluated at 2, 7, and 14 days after reperfusion. Morphologically, the naloxone-treated group showed better-preserved ganglion cells, nerve fiber layer, and inner nuclear layer. Morphometrically, in the treated groups, inner retinal thickness at all three time points and ganglion cell counts at 7 days showed higher values than vehicle controls. This beneficial effect of naloxone was dose-dependent with a minimal effective total dose of 6 mg/kg. A possible role of opiate receptors in retinal ischemia is suggested.
Lam
T T
TT
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago.
Takahashi
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Tso
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MO
D000818:Animals; D002452:Cell Count; D004305:Dose-Response Relationship, Drug; D007274:Injections, Intraperitoneal; D007511:Ischemia / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D009270:Naloxone / Q000494:pharmacology / Q000627:therapeutic use*; D009412:Nerve Fibers / Q000187:drug effects / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000648:ultrastructure; D051381:Rats; D011917:Rats, Inbred Lew; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000648:ultrastructure; D012171:Retinal Vessels
D009270:Naloxone