Calcium antagonists in N-methyl d-aspartate-induced retinal injury.
OBJECTIVE
To detect the neuroprotective role of nimodipine and dantrolene in N-methyl- d-aspartate (NMDA)-induced retinal injury.


METHODS
In this study we used two calcium antagonists which have two different modes of action, nimodipine and dantrolene, to prevent NMDA-induced retinal ischemia in guinea pigs. In 40 animals we injected nimodipine (n=10), dantrolene (n=10), a combination of both (n=10) or sterile 0.9% NaCl solution as a placebo (n=10) before intravitreal injection of NMDA. We enucleated one eye of each animal after 48 hours and performed histopathologic examination. We also measured malondialdehyde (MDA) levels in retinal homogenates as a marker of ischemic injury.


RESULTS
Our results indicate that ganglion cells of the retina were preserved mostly by nimodipine, followed by combined nimodipine-dantrolene, and dantrolene respectively. The ganglion cell count was statistically significantly higher in cases where we used calcium antagonists than in the control group (p<0.05). We also found that MDA was significantly reduced by calcium antagonists compared to the control group (p<0.05).


CONCLUSIONS
Our data show that nimodipine and dantrolene both have potential neuroprotective effects; nimodipine preserved retinal ganglion cells to a greater extent than dantrolene from NMDA-induced retinal injury.
Kaya
Murat
M
Department of Ophthalmology, Abant Izzet Baysal University Düzce Medical School, Konuralp-Düzce, Turkey. mtunc@isbank.net.tr
Tunç
Murat
M
Ozdemir
Talha
T
Altuntaş
Irfan
I
D000818:Animals; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D002452:Cell Count; D003620:Dantrolene / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D006168:Guinea Pigs; D007511:Ischemia / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D016202:N-Methylaspartate / Q000633:toxicity*; D009553:Nimodipine / Q000627:therapeutic use; D012160:Retina / Q000187:drug effects; D012164:Retinal Diseases / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D012171:Retinal Vessels / Q000187:drug effects* / Q000378:metabolism
D002121:Calcium Channel Blockers; D018690:Excitatory Amino Acid Agonists; D008315:Malondialdehyde; D009553:Nimodipine; D016202:N-Methylaspartate; D003620:Dantrolene