Abstract
Abstract: :
Purpose:This study was designed to investigate a nitric oxide (NO) donative effect of topical nipradilol, an α1, ß-blocker, on the interactions in the retinal microcirculation. Methods:Male Brown-Norway rats were given NG-nitro-l-arginine methyl ester (L-NAME) in drinking water for 2 weeks to inhibit production of intrinsic NO in the retinal endothelium. Rats in group A received one eyedrop of 1% nipradilol twice daily. Rats in group B received one eyedrop each of 0.5% timolol and 0.125% bunazosin twice daily during the 2 weeks. Animals in group C had vehicle instillation only in the same way. Control animals were given drinking water without L-NAME and had vehicle instillation. The leukocyte velocity in the retinal capillaries and the number of leukocytes trapped in the retina were evaluated with acridine orange digital fluorography. Results:The number of trapped leukocytes was significantly greater in groups A, B and C than in control (22.78±0.36, 26.04±0.31, 27.13±0.55 and 5.43±0.26 cells/mm2, respectively, p<0.001). The rats received nipradilol showed less trapped leukocytes than the other groups (p<0.01).there were no significant differences in leukocyte velocities among all groups. Conclusion:The results suggest that the inhibition of NO production causes a disturbance of leukocyte circulation in the retina and that topical nipradilol appears to have a NO donative effect of alleviating leukocyte-endothelial interaction in the retinal microcirculation.
Keywords: 390 drug toxicity/drug effects • 491 nitric oxide • 554 retina