Expression Of NMDA Receptor In The Rat And Carp Retina

Objective:N-methyl-D-aspartate receptors (NMDARs), are one of the ionotropic glutamate receptors, which play key roles in the neuronal communication in the retina. The aim of this study is to investigate NMDA receptor subunit1(NR1) protein expression and distribution in the rat retina.Methods:We examined the qualitative expression and spatial distribution of NR1protein in the rat retina by western blot analysis and immunofluorescence double labeling respectively.Results:Western blot analysis declared that NR1protein was present in the rat retina, and the specificity of the NR1antibody. We showed that labeling for NR1was diffusely distributed in the outer plexiform layer (OPL) and throughout full thickness of the inner plexiform layer (IPL). The NR1-immunoreactivity (IR) was also displayed in a variety of cells in the inner nuclear layer (INL) and the ganglion cell layer (GCL). Interestingly, NR1was expressed in both rod and cone bipolar cells identified by specific bipolar cell markers Chx10, protein kinase C (PKC) and recoverin. All the amacrine cells that we studied, including cholinergic, dopaminergic, GABAergic and glycinergic amacrine cells, were NR1-IR positive. In the ganglion cell layer, NR1-IR was expressed in all cells that were positive for the ganglion cell maker Brn3a.Conclusion:Our work suggests that the NR1subunit is expressed more widely than was previously appreciated, which providing additional evidence for a role of NR1in neuronal transmitter and synaptic plasticity. We provide important evidence showing that retina bipolar cells could have NMDA receptor expression, that involve in modulation of vertical retina signal transmission. Objective:The aim of this study is to investigate ionotropic glutamate receptors NMDA receptor regulation subunits3A and3B (NR3A-NR3B) protein expression and distribution.in the carp retina.Methods:We examined the qualitative expression and spatial distribution of NR3A and NR3B protein in the carp retina by western blot analysis and immunofluorescence labeling respectively.Results:Western blot analysis declared that NR3A and NR3B proteins were present in the carp retina, and the specificity of these two antibodies. We showed that labeling for NR3A was diffusely distributed in the outer plexiform layer (OPL) and a punctate or diffusion-like distribution in the inner plexiform layer (IPL). The NR3A-immunoreactivity (IR) was also displayed in a variety of cells in the inner nuclear layer (INL) and the ganglion cell layer (GCL). Interestingly, NR3A was strongly expressed in the cell bodies, axons and axon terminals of the outer nuclear layer (ONL). The NR3B immunoreactive positive products were diffusely distributed in the OPL and IPL, also in a few cells in the INL and GCL, but the positive signals were weak. Some cells of ONL have a stronger immune positive reaction.Conclusion:Our work suggests that the NR3A and NR3B subunits are widely expressed in the carp retina, which providing additional evidence for a role of NR3in neuronal transmitter and synaptic plasticity. We provide important evidences showing that NR3subunits expression in photoreceptor cells may be involved in the excitotoxicity in the course of age-related macular degeneration and inherited retinal degenerative diseases, and their expression in ganglion cells indicate that NR3subunits is also likely to participate in the ganglion cell apoptosis caused by excitotoxicity in glaucoma or retinal ischemic diseases.