Neuroprotection of retinal ganglion cell function and their central nervous system targets

Technological advances have enabled the observation of a large number of retinal ganglion cells (RGCs) in an objective manner. In animal models, it has been shown how retinal ischaemia induces profound functional and structural alterations of the inner retinal and RGC layers by 3 months. These findings reflect degeneration of the inner retinal layers, the RGC population and of the retinotectal projection. Functionally, this implies a permanent disconnection of the retina from its main retinorecipient target region in the brain. Brimonidine, a selective α-2 adrenergic agonist, has been shown to activate α-2 adrenergic receptors in the retina and promote the survival and function of RGCs post-injury. This agent may prevent or diminish ischaemia-induced alterations in the inner and RGC areas as well as in the main retinofugal projection. Understanding the pattern of degeneration that occurs in the major retinofugal pathway following retinal ischaemia will benefit ongoing studies conducted to develop neuroprotectant-based treatment strategies for progressive neuropathies such as glaucoma.