title: NMDA receptor activation modulates programmed cell death during early post-natal retinal development: a BDNF-dependent mechanism.
abstract: Glutamate is a classical excitotoxin of the central nervous system (CNS), but extensive work demonstrates neuroprotective roles of this neurotransmitter in developing CNS. Mechanisms of glutamate-mediated neuroprotection are still under scrutiny. In this study, we investigated mediators of glutamate-induced neuroprotection, and tested whether this neurotransmitter controls programmed cell death in the developing retina. The protective effect of N-methyl-d-aspartate (NMDA) upon differentiating cells of retinal explants was completely blocked by a neutralizing antibody to brain-derived neurotrophic factor (BDNF), but not by an antibody to neurotrophin-4 (NT-4). Consistently, chronic activation of NMDA receptor increased the expression of BDNF and trkB mRNA, as well as BDNF protein content, but did not change the content of NT-4 mRNA in retinal tissue. Furthermore, we showed that in vivo inactivation of NMDA receptor by intraperitoneal injections of MK-801 increased natural cell death of specific cell populations of the post-natal retina. Our results show that chronic activation of NMDA receptors in vitro induces a BDNF-dependent neuroprotective state in differentiating retinal cells, and that NMDA receptor activation controls programmed cell death of developing retinal neurons in vivo.
authors.affiliation: Laboratorio de Neurogenese, Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brazil. martinsr@biof.ufrj.br
authors.forename: Rodrigo A P
authors.initials: RA
authors.lastname: Martins
authors.forename: Mariana S
authors.initials: MS
authors.lastname: Silveira
authors.forename: Marco R
authors.initials: MR
authors.lastname: Curado
authors.forename: Angela I
authors.initials: AI
authors.lastname: Police
authors.forename: Rafael
authors.initials: R
authors.lastname: Linden
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000502:physiology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000235:genetics / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D020813:Receptor, trkB / Q000235:genetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*; D012160:Retina / Q000254:growth & development / Q000502:physiology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D009414:Nerve Growth Factors; D018696:Neuroprotective Agents; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D020813:Receptor, trkB; C073922:neurotrophin 4