Resumo

LEE-RIVERA, Irene  e  LOPEZ-COLOME, Ana María. Structure-function relationship of NMDA receptors in the retina. TIP [online]. 2005, vol.8, n.2, pp.71-81. ISSN 1405-888X.

The multiple actions of glutamate in the retina, as a neurotransmitter, a trophic factor or a neurotoxin, are directly related to the heteromeric composition of the NMDA type of glutamate receptors present in this tissue. The tetrameric NMDARs include two NR1 subunits which form the calcium-permeable cation channel, in addition to NR2 and NR3 subunits which modulate its activity.

Recent results demonstrate that retinal NMDARs might include tissue-specific NR1 splice variants and NR2 subunits, in both mature and embryonic tissue, which determine structural and functional differences with brain receptors. As a consequence, drugs shown to protect brain neurons from glutamate-induced neuronal death, are ineffective in the retina.

The clarification of the precise subunit composition of NMDARs in the retina will allow the future design of drugs aimed to prevent neuronal loss in pathological conditions such as glaucoma, vascular occlusion, optic neuropathy and ischemia, in which glutamate excitotoxicity seems to be involved.

Palavras-chave : Embryonic development; neurotransmission; NR1; NR2; glutamate receptors.