Possible role of excitotoxicity in the pathogenesis of glaucoma

Abstract

Excitotoxicity describes the process of neuronal injury by excess stimulation of amino acid receptors. This form of insult was first described in the retina, and subsequently has been shown to be an important component of the pathogenesis of ischaemic and traumatic injury in the central nervous system. Furthermore, there is increasing evidence that excitotoxicity is involved in several chronic neurological conditions, and anti-excitotoxic treatment has already been approved for some of these conditions. A large-scale trial is currently underway that will determine the efficacy of an anti-excitotoxic drug (memantine) in the management of glaucoma. This review provides an overview of neurotransmission and the mechanisms of excitotoxicity. The evidence for excitotoxicity as a component of certain neurological diseases, including glaucoma, is discussed.

Evaluation of corpus geniculatum laterale and vitreous fluid by magnetic resonance spectroscopy in patients with glaucoma; a preliminary study

“…16,17 Glutamate is a transmitter that exists widely in the brain and medulla spinalis, and is responsible for 75% of excitatory transmission. 1,[4][5][6] Glutamate triggers oxidative injury and free radical injury. It is also able to stimulate nitric oxide formation, which is an important free radical precursor, by activating nitric oxide synthase (iNOS or NOS-2) enzyme.…”

“…3 Glutamate is an important transmitter existing widely in the central nervous system (CNS) and is responsible for excitatory transmission. 1,[4][5][6] Its neurotoxic effect (excitotoxicity) was first seen through experimental studies on mice. 4 In further studies, it was determined that glutamate may be effective in the pathogenesis of some neurodegenerative diseases of CNS.…”

“…1,[4][5][6] Its neurotoxic effect (excitotoxicity) was first seen through experimental studies on mice. 4 In further studies, it was determined that glutamate may be effective in the pathogenesis of some neurodegenerative diseases of CNS. 4 In the light of the apoptosis theory indicated as a factor in glaucoma pathophysiology, an increase in the level of glutamate known for its neurotoxic effects, is expected on the optic disc vitreous and LGB region.…”

“…4 In further studies, it was determined that glutamate may be effective in the pathogenesis of some neurodegenerative diseases of CNS. 4 In the light of the apoptosis theory indicated as a factor in glaucoma pathophysiology, an increase in the level of glutamate known for its neurotoxic effects, is expected on the optic disc vitreous and LGB region. Research carried out on glaucoma patients showed discrepancies in their glutamate levels in the vitreous.…”

Wallerian-like axonal degeneration in the optic nerve after excitotoxic retinal insult: an ultrastructural study

“…Excitotoxicity, the mechanism involved in the pathogenesis of neurological diseases, including stroke, motor neuron disease (MND), Alzheimer's disease (AD), retinal ischemia and glaucoma [1-12], is classically considered as a somatodendritic insult due to prolonged or excessive activation of excitatory amino acid receptors. Studies have also indicated axonopathy as an early feature in neurodegenerative diseases associated with excitotoxicity [13-16].…”