Expression of ionotropic glutamate receptors in the retina of the rdta transgenic mouse.
BACKGROUND
The expression of retinal CaMKII is up-regulated in the retina of the rdta mouse in which rod photoreceptors are genetically ablated. As ionotropic glutamate receptors are known substrates of CAMKII, this study set out to determine if the protein levels of ionotropic glutamate receptors in the rdta mouse retina are also affected.


RESULTS
The NMDA receptor subunits (NR1, NR2A/B) and the GluR1; AMPA receptor subunit (GluR1) were examined in immunolabeled western blots. The results demonstrate that the amounts of NR1 and NR2A/B receptor subunits are significantly increased in crude synaptic membrane fractions isolated from retinae of the rdta mice when compared to their normal, littermate controls. The GluR1 receptor subunit and its phosphorylation are simultaneously increased in retinae of the rdta mice.


CONCLUSIONS
These data indicate that the NMDA receptors and AMPA (GluR1) receptors are altered in the retinae of rdta mice that lack rod photoreceptors. Because the rods are lost at an early stage in development, it is likely that these results are indicative of synaptic reorganization in the retina.
Liu
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Department of Ophthalmology and Visual Science, University of Louisville School of Medicine, Louisville, Kentucky, USA. 10liu002@gwise.louisville.edu
Laabich
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A
Hardison
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Cooper
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D000199:Actins / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D051379:Mice; D008822:Mice, Transgenic; D010766:Phosphorylation; D018091:Receptors, AMPA / Q000032:analysis / Q000096:biosynthesis; D017470:Receptors, Glutamate / Q000032:analysis / Q000096:biosynthesis*; D016194:Receptors, N-Methyl-D-Aspartate / Q000032:analysis / Q000096:biosynthesis; D012160:Retina / Q000737:chemistry / Q000378:metabolism*; D012164:Retinal Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D017948:Retinal Rod Photoreceptor Cells / Q000473:pathology; D013570:Synaptic Membranes / Q000737:chemistry / Q000378:metabolism
D000199:Actins; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor