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Abstract #50567 Published in IGR 14-2
Changes in optic nerve head circulation in response to vasoactive agents: inter-eye comparison in monkeys with experimental unilateral glaucoma
Mayama C; Ishii K; Ota T; Tomidokoro A; Araie MInvestigative Ophthalmology and Visual Science 2012; 53: 5771-5778
PURPOSE: To investigate circulatory changes in the optic nerve head (ONH) in response to vasoactive agents including calcium antagonists, a substrate of nitric oxide (NO), and an inhibitor of NO synthase (NOS) in monkeys with experimental unilateral glaucoma. METHODS: Argon laser cautery to the trabecular meshwork was used to create experimental unilateral glaucoma in nine monkeys. The effects of systemic lomerizine or nilvadipine, calcium-antagonists, L-arginine (a substrate of NO), and with NG-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor), on the ONH tissue blood velocity (NBONH) was determined by the laser speckle method in both eyes of the nine monkeys after establishment of unilateral laser-induced glaucoma. RESULTS: Lomerizine and nilvadipine significantly increased NBONH in the non-laser treated eyes (P = 0.039 and 0.008, respectively), while significant but less relative increases were found in the contralateral experimental glaucomatous eyes with significant inter-eye differences (P = 0.036 and 0.011, respectively). L-arginine significantly increased NBONH in both eyes (P = 0.71). L-NAME had no significant effects on NBONH in the experimental glaucoma eyes; however, it produced a significant decrease in the non-laser treated eyes (P = 0.036). CONCLUSIONS: In experimental glaucomatous eyes the reactivity of ONH vessels to calcium-antagonists was preserved, but was significantly reduced. The effects of a NOS inhibitor disappeared; however reactivity to a substrate of NO was normal. These date indicate that in experimental glaucoma, vasodilator reactivity in the peripheral vasculature of the ONH is preserved, but with functional alterations in reactivity to the NO system.
Department of Ophthalmology, The University of Tokyo Graduate School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
Full articleClassification:
5.2 Primates (Part of: 5 Experimental glaucoma; animal models)
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)