Ionotropic glutamate receptors during the development of the chick retina

Abstract

Glutamate is the main neurotransmitter of photoreceptors, bipolar cells, and ganglion cells of the vertebrate retina. Three main classes of ionotropic glutamate receptors comprising different subunits can be distinguished: AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxasolepropionate), KA (kainate), and NMDA (N-methyl-D-aspartate). This study was undertaken to characterize the AMPA (GluR1, GluR2/3, and GluR4), KA (GluR5/6/7), and NMDA (NR1) ionotropic glutamate receptor subunits and to determine their distribution during the development of the chick retina by Western blotting and immunohistochemistry. Western blotting analysis at 1 day after hatching indicated that the antibodies against GluR1, 2/3, 4, and 5/6/7 and NR1 recognized specifically a single band of 100-110 kDa. In turn, immunohistochemistry at P1 showed that all subunits were expressed in cells of the inner nuclear and ganglion cell layers of the chick retina, mostly amacrine and ganglion cells, and their processes in the inner plexiform layer. In addition, stained processes in the outer plexiform layer were observed with the antibodies against GluR2/3, GluR4, and GluR5/6/7. Although all subunits appeared around E5-E6 in the prospective ganglion cell layer, and later in the prospective inner nuclear layer, the distribution of cells containing these glutamate receptor subunits revealed distinct ontogenetic patterns. This multiplicity of glutamate receptors may contribute to different processes that occur in the chick retina during development.

The Reactivity, Distribution and Abundance of Non-Astrocytic Inner Retinal Glial (NIRG) Cells Are Regulated by Microglia, Acute Damage, and IGF1

“…Thus, it seems likely that both NIRG cells and microglia express IGF1-receptors and that IGF1 acts directly on these cells. By contrast, the effects of NMDA on the microglia and NIRG cells are likely to be indirect; studies have failed to provide evidence that NMDA receptors are expressed by cells scattered in the IPL [27], [28], [29].…”

Molecular dynamics of photoreceptor synapse formation in the developing chick retina

“…Mouse monoclonal calbindin antibody (Sigma, St. Louis, MO; CL300) was made against chicken gut calbindin D‐28 and recognizes its 45 Ca‐binding spot in a two‐dimensional gel (manufacturer's observation); it has also been analyzed by indirect immunofluorescence, immunoenzymatic labeling, and radioimmunoassay and in a comparison of retinas from wild‐type and calbindin −/− mice (Wässle et al,1998). Polyclonal antibodies against the rat GluR4 peptide sequence (RQSSGLAVIASDLP) recognize a single band of ∼110 kDa in size (Silveira dos Santos Bredariol and Hamassaki‐Britto,2001). Lim1/2 monoclonal antibodies against amino acid residues 1–360 of rat Lim2 have shown specificity by immunohistochemistry and in situ hybridization (Tsuchida et al,1994).…”

The Molecular Pharmacology and Cell Biology of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptors

“…Developmental changes in the expression levels of AMPARs in hippocampal organotypic slice cultures (Fabian-Fine et al, 2000) and living cultured hippocampal neurons have also been reported (Pickard et al, 2000; Molnar et al, 2002), concluding that maturation of synapses may be retarded in vitro. AMPAR expression is also developmentally regulated in the spinal cord (Jakowec et al, 1995; Kalb and Fox, 1997), the visual system (Silveira dos Santos Bredariol and Hamassaki-Britto, 2001; Batista et al, 2002; Hack et al, 2002), and the auditory system (Sugden et al, 2002). During neonatal development, AMPAR incorporation into the plasma membrane occurs prior to synaptogenesis when GluR1-containing AMPARs cluster at potential postsynaptic sites (Martin et al, 1998).…”