Skip to main content Accessibility help

Alteration of retinal intrinsic survival signal and effect of α2–adrenergic receptor agonist in the retina of the chronic ocular hypertension rat

  • HWA SUN KIM (a1), YONG IK CHANG (a1), JIE HYUN KIM (a1) and CHAN KEE PARK (a1)


The purpose of this study is to examine the retinal expression of intrinsic cell survival molecules and to elucidate the effect of an α2-adrenergic receptor agonist in the chronic ocular hypertensive rat model. Chronic ocular hypertension was induced in both eyes of each rat by episcleral vein cauterization. Two five-microliter drops of the selective α2-adrenoceptor agonist brimonidine 0.2% (Alphagan; Allergan Inc., Irvine, CA, USA) were topically administered twice daily for up to eight weeks in one eye. The fellow eye received balanced salt solution as a control. Protein and mRNA expression were evaluated at 1, 4, and 8 weeks after injury. Retinal expression of BDNF, Akt, and GFAP was assessed using immunohistochemistry. Retinal levels of mRNA for BDNF, bcl-2, and bcl-xL were determined using semi-quantitative RT-PCR. Retinal ganglion cell (RGC) density was evaluated after retrograde labeling with 4-Di-10-ASP (DiA). A significant decrease in RGC density was observed in ocular hypertensive eyes. Cauterized eyes showed an increase in GFAP expression from one week after injury, and the expression of bcl-2, bcl-xL, and BDNF mRNA was also increased. Treatment of ocular hypertensive eyes with brimonidine resulted in a reduction in RGC loss, a decrease in the level of GFAP immunoreactivity, and an increment in BDNF mRNA and p-Akt expression. Brimonidine appears to protect RGCs from neurodegeneration through mechanisms involving α2-adrenergic receptor mediated survival signal activation and up-regulation of endogenous neurotrophic factor expression in the chronic ocular hypertensive rat retina.


Corresponding author

Address correspondence and reprint requests to: Chan Kee Park, Department of Ophthalmology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-ku, Seoul 137-701, Korea. E-mail:


Hide All


Adams, J.M. & Cory, S. (1998). The Bcl-2 protein family: arbiters of cell survival. Science 281, 13221326.
Akman, A., Cetinkaya, A., Akova, Y.A. & Ertan, A. (2005). Comparison of additional intraocular pressure-lowering effects of latanoprost vs brimonidine in primary open-angle glaucoma patients with intraocular pressure uncontrolled by timolol-dorzolamide combination. Eye 19, 145151.
Baptiste, D.C., Hartwick, A.T., Jollimore, C.A., Baldridge, W.H., Chauhan, B.C., Tremblay, F. & Kelly, M.E. (2002). Comparison of the neuroprotective effects of adrenoceptor drugs in retinal cell culture and intact retina. Investigative and Ophthalmology & Visual Science 43, 26662676.
Bennett, J.L., Zeiler, S.R. & Jones, K.R. (1999). Patterned expression of BDNF and NT-3 in the retina and anterior segment of the developing mammalian eye. Investigative Ophthalmology Visual Science 40, 29963005.
Cory, S. & Adams, J.M. (2002). The Bcl2 family: Regulators of the cellular life-or-death switch. Nature Reviews. Cancer 2, 647656.
Dolcet, X., Egea, J., Soler, R.M., Martin-Zanca, D. & Comella, J.X. (1999). Activation of phosphatidylinositol 3-kinase, but not extracellular-regulated kinases, is necessary to mediate brain-derived neurotrophic factor-induced motoneuron survival. Journal of Neurochemistry 73, 521531.
Dolcet, X., Soler, R.M., Gould, T.W., Egea, J., Oppenheim, R.W. & Comella, J.X. (2001). Cytokines promote motoneuron survival through the Janus kinase-dependent activation of the phosphatidylinositol 3-kinase pathway. Molecular and Cell Neuroscience 18, 619631.
Encinas, M., Iglesias, M., Llecha, N. & Comella, J.X. (1999). Extracellular-regulated kinases and phosphatidylinositol 3-kinase are involved in brain-derived neurotrophic factor-mediated survival and neuritogenesis of the neuroblastoma cell line SH-SY5Y. Journal of Neurochemistry 73, 14091421.
Evan, G. & Littlewood, T. (1998). A matter of life and cell death. Science 281, 13171322.
Facchinetti, F., Dawson, V.L. & Dawson, T.M. (1998). Free radicals as mediators of neuronal injury. Cellular and Molecular Neurobiology 18, 667682.
Faden, A.I. (1987). Pharmacotherapy in spinal cord injury: a critical review of recent developments. Clinical Neuropharmacology 10, 193204.
Gao, H., Qiao, X., Cantor, L.B. & WuDunn, D. (2002). Up-regulation of brain-derived neurotrophic factor expression by brimonidine in rat retinal ganglion cells. Archives of Ophthalmology 120, 797803.
Hetman, M., Kanning, K., Cavanaugh, J.E. & Xia, Z. (1999). Neuroprotection by brain-derived neurotrophic factor is mediated by extracellular signal-regulated kinase and phosphatidylinositol 3-kinase. The Journal of Biological Chemistry 274, 2256922580.
Ishii, Y., Kwong, J.M. & Caprioli, J. (2003). Retinal ganglion cell protection with geranylgeranylacetone, a heat shock protein inducer, in a rat glaucoma model. Investigative Ophthalmology & Visual Science 44, 19821992.
Kent, A.R., Nussdorf, J.D., David, R., Tyson, F., Small, D. & Fellows, D. (2001). Vitreous concentration of topically applied brimonidine tartrate 0.2%. Ophthalmology 108, 784787.
Kermer, P., Klocker, N., Labes, M. & Bahr, M. (1998). Inhibition of CPP32-like proteases rescues axotomized retinal ganglion cells from secondary cell death in vivo. Journal of Neuroscience 18, 46564662.
Kermer, P., Klocker, N., Labes, M. & Bahr, M. (2000). Insulin-like growth factor-I protects axotomized rat retinal ganglion cells from secondary death via PI3-K-dependent Akt phosphorylation and inhibition of caspase-3 In vivo. Journal of Neuroscience 20, 28.
Kermer, P., Klocker, N., Labes, M., Thomsen, S., Srinivasan, A. & Bahr, M. (1999). Activation of caspase-3 in axotomized rat retinal ganglion cells in vivo. FEBS Letters 453, 361364.
Kim, H.S. & Park, C.K. (2005). Retinal ganglion cell death is delayed by activation of retinal intrinsic cell survival program. Brain Research 1057, 1728.
Klocker, N., Kermer, P., Weishaupt, J.H., Labes, M., Ankerhold, R. & Bahr, M. (2000). Brain-derived neurotrophic factor-mediated neuroprotection of adult rat retinal ganglion cells in vivo does not exclusively depend on phosphatidyl-inositol-3'-kinase/protein kinase B signaling. Journal of Neuroscience 20, 69626967.
Ko, M.L., Hu, D.N., Ritch, R., Sharma, S.C. & Chen, C.F. (2001). Patterns of retinal ganglion cell survival after brain-derived neurotrophic factor administration in hypertensive eyes of rats. Neuroscience Letters 305, 139142.
Levkovitch-Verbin, H., Quigley, H.A., Martin, K.R., Valenta, D., Baumrind, L.A. & Pease, M.E. (2002). Translimbal laser photocoagulation to the trabecular meshwork as a model of glaucoma in rats. Investigative Ophthalmology & Visual Science 43, 402410.
Levkovitch-Verbin, H., Quigley, H.A., Martin, K.R., Zack, D.J., Pease, M.E. & Valenta, D.F. (2003). A model to study differences between primary and secondary degeneration of retinal ganglion cells in rats by partial optic nerve transection. Investigative Ophthalmolology & Visual Science 44, 33883393.
Lynch, D.R. & Dawson, T.M. (1994). Secondary mechanisms in neuronal trauma. Current Opinions in Neurology 7, 510516.
Maier, C., Steinberg, G.K., Sun, G.H., Zhi, G.T. & Maze, M. (1993). Neuroprotection by the alpha 2-adrenoreceptor agonist dexmedetomidine in a focal model of cerebral ischemia. Anesthesiology 79, 306312.
Martin, K.R., Levkovitch-Verbin, H., Valenta, D., Baumrind, L., Pease, M.E. & Quigley, H.A. (2002). Retinal glutamate transporter changes in experimental glaucoma and after optic nerve transection in the rat. Investigative & Ophthalmology Visual Science 43, 22362243.
Martin, K.R., Quigley, H.A., Zack, D.J., Levkovitch-Verbin, H., Kielczewski, J., Valenta, D., Baumrind, L., Pease, M.E., Klein, R.L. & Hauswirth, W.W. (2003). Gene therapy with brain-derived neurotrophic factor as a protection: Retinal ganglion cells in a rat glaucoma model. Investigative Ophthalmology & Visual Science 44, 43574365.
Matsuzaki, H., Namikawa, K., Kiyama, H., Mori, N. & Sato, K. (2004). Brain-derived neurotrophic factor rescues neuronal death induced by methamphetamine. Biological Psychiatry 55, 5260.
McKinnon, S.J. (1997). Glaucoma, apoptosis, and neuroprotection. Current Opinions in Ophthalmology 8, 2837.
Miller, D.B., Blackman, C.F. & O'Callaghan, J.P. (1987). An increase in glial fibrillary acidic protein follows brain hyperthermia in rats. Brain Research 415, 371374.
Moore, C.G., Epley, D., Milne, S.T. & Morrison, J.C. (1995). Long-term non-invasive measurement of intraocular pressure in the rat eye. Current Eye Research 14, 711717.
Moore, C.G., Milne, S.T. & Morrison, J.C. (1993). Noninvasive measurement of rat intraocular pressure with the Tono-Pen. Investigative Ophthalmology & Visual Science 34, 363369.
Morrison, J.C., Moore, C.G., Deppmeier, L.M., Gold, B.G., Meshul, C.K. & Johnson, E.C. (1997). A rat model of chronic pressure-induced optic nerve damage. Experimental Eye Research 64, 8596.
Nakamura, T., Komiya, M., Gotoh, N., Koizumi, S., Shibuya, M. & Mori, N. (2002). Discrimination between phosphotyrosine-mediated signaling properties of conventional and neuronal Shc adapter molecules. Oncogene 21, 2231.
Nakamura, T., Muraoka, S., Sanokawa, R. & Mori, N. (1998). N-Shc and Sck, two neuronally expressed Shc adapter homologs. Their differential regional expression in the brain and roles in neurotrophin and Src signaling. Journal of Biological Chemistry 273, 69606967.
Nakamura, T., Sanokawa, R., Sasaki, Y., Ayusawa, D., Oishi, M. & Mori, N. (1996). N-Shc: A neural-specific adapter molecule that mediates signaling from neurotrophin/Trk to Ras/MAPK pathway. Oncogene 13, 11111121.
Nakazawa, T., Tamai, M. & Mori, N. (2002b). Brain-derived neurotrophic factor prevents axotomized retinal ganglion cell death through MAPK and PI3K signaling pathways. Investigative Ophthalmology & Visual Science 43, 33193326.
Naskar, R., Wissing, M. & Thanos, S. (2002). Detection of early neuron degeneration and accompanying microglial responses in the retina of a rat model of glaucoma. Investigative Ophthalmology & Visual Science 43, 29622968.
Neufeld, A.H. (1999). Nitric oxide: a potential mediator of retinal ganglion cell damage in glaucoma. Survey of Ophthalmology 43 (Suppl. 1), S129135.
Oltvai, Z.N., Milliman, C.L. & Korsmeyer, S.J. (1993). Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death. Cell 74, 609619.
Pease, M.E., McKinnon, S.J., Quigley, H.A., Kerrigan-Baumrind, L.A. & Zack, D.J. (2000). Obstructed axonal transport of BDNF and its receptor TrkB in experimental glaucoma. Investigative Ophthalmology & Visual Science 41, 764774.
Rudzinski, M., Wong, T.P. & Saragovi, H.U. (2004). Changes in retinal expression of neurotrophins and neurotrophin receptors induced by ocular hypertension. Journal of Neurobiology 58, 341354.
Shareef, S.R., Garcia-Valenzuela, E., Salierno, A., Walsh, J. & Sharma, S.C. (1995). Chronic ocular hypertension following episcleral venous occlusion in rats. Experimental Eye Research 61, 379382.
Tatton, W., Chen, D., Chalmers-Redman, R., Wheeler, L., Nixon, R. & Tatton, N. (2003). Hypothesis for a common basis for neuroprotection in glaucoma and Alzheimer's disease: Anti-apoptosis by alpha-2-adrenergic receptor activation. Survey in Ophthalmology 48 (Suppl. 1), S2537.
Tatton, W.G., Chalmers-Redman, R.M., Sud, A., Podos, S.M. & Mittag, T.W. (2001). Maintaining mitochondrial membrane impermeability. an opportunity for new therapy in glaucoma? Survey in Ophthalmology 45 (Suppl. 3), S277283; discussion S295–276.
Ueda, J., Sawaguchi, S., Hanyu, T., Yaoeda, K., Fukuchi, T., Abe, H. & Ozawa, H. (1998). Experimental glaucoma model in the rat induced by laser trabecular photocoagulation after an intracameral injection of India ink. Japan Journal of Ophthalmology 42, 337344.
Vijayan, V.K., Lee, Y.L. & Eng, L.F. (1990). Increase in glial fibrillary acidic protein following neural trauma. Molecular Chemical Neuropathology 13, 107118.
Vincent, A.M., Mobley, B.C., Hiller, A. & Feldman, E.L. (2004). IGF-I prevents glutamate-induced motor neuron programmed cell death. Neurobiological Disorders 16, 407416.
Vorwerk, C.K., Naskar, R., Schuettauf, F., Quinto, K., Zurakowski, D., Gochenauer, G., Robinson, M.B., Mackler, S.A. & Dreyer, E.B. (2000). Depression of retinal glutamate transporter function leads to elevated intravitreal glutamate levels and ganglion cell death. Investigative Ophthalmology & Visual Science 41, 36153621.
Wagey, R., Lurot, S., Perrelet, D., Pelech, S.L., Sagot, Y. & Krieger, C. (2001). Phosphatidylinositol 3-kinase activity in murine motoneuron disease: The progressive motor neuropathy mouse. Neuroscience 103, 257266.
Wheeler, L.A., Gil, D.W. & WoldeMussie, E. (2001). Role of alpha-2 adrenergic receptors in neuroprotection and glaucoma. Survey of Ophthalmology 45 (Suppl. 3), S290294; discussion S295–296.
Wheeler, L.A., Lai, R. & Woldemussie, E. (1999). From the lab to the clinic: activation of an alpha-2 agonist pathway is neuroprotective in models of retinal and optic nerve injury. European Journal of Ophthalmology 9 (Suppl. 1), S1721.
Wheeler, L.A. & Woldemussie, E. (2001). Alpha-2 adrenergic receptor agonists are neuroprotective in experimental models of glaucoma. European Journal of Ophthalmology 11 (Suppl. 2), S3035.
Whitson, J.T., Henry, C., Hughes, B., Lee, D.A., Terry, S. & Fechtner, R.D. (2004). Comparison of the safety and efficacy of dorzolamide 2% and brimonidine 0.2% in patients with glaucoma or ocular hypertension. Journal of Glaucoma 13, 168173.
Wirt, H., Draeger, J., Rumberger, E., Deutsch, C. & Dauper, J. (1989). Comparative studies of the calibration of new electronic automatic tonometers. Fortschritte der Ophthalmologie 86, 403406.
WoldeMussie, E., Ruiz, G., Wijono, M. & Wheeler, L.A. (2001). Neuroprotection of retinal ganglion cells by brimonidine in rats with laser-induced chronic ocular hypertension. Investigative Ophthalmology & Visual Science 42, 28492855.
Zamzami, N., Brenner, C., Marzo, I., Susin, S.A. & Kroemer, G. (1998). Subcellular and submitochondrial mode of action of Bcl-2-like oncoproteins. Oncogene 16, 22652282.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed