Synaptic localization of P2X7 receptors in the rat retina
- 10 March 2004
- journal article
- Published by Wiley in Journal of Comparative Neurology
- Vol. 472 (1), 13-23
- https://doi.org/10.1002/cne.20045
Abstract
The distribution of P2X7 receptor (P2X7R) subunits was studied in the rat retina using a subunit‐specific antiserum. Punctate immunofluorescence was observed in the inner and outer plexiform layers. Double labeling of P2X7 and the horizontal cell marker, calbindin, revealed extensive colocalization in the outer plexiform layer (OPL). Significant colocalization of P2X7R and kinesin, a marker of photoreceptor ribbons, was also observed, indicating that this receptor may be expressed at photoreceptor terminals. Furthermore, another band of P2X7R puncta was identified below the level of the photoreceptor terminals, adjacent to the inner nuclear layer (INL). This band of P2X7R puncta colocalized with the active‐zone protein, bassoon, suggesting that “synapse‐like” structures exist outside photoreceptor terminals. Preembedding immunoelectron microscopy demonstrated P2X7R labeling of photoreceptor terminals adjacent to ribbons. In addition, some horizontal cell dendrites and putative “desmosome‐like” junctions below cone pedicles were labeled. In the inner plexiform layer (IPL), P2X7R puncta were observed surrounding terminals immunoreactive for protein kinase C‐α, a marker of rod bipolar cells. Double labeling with bassoon in the IPL revealed extensive colocalization, indicating that P2X7R is likely to be found at conventional cell synapses. This finding was confirmed at the ultrastructural level: only processes presynaptic to rod bipolar cells were found to be labeled for the P2X7R, as well as other conventional synapses. These findings suggest that purines play a significant role in neurotransmission within the retina, and may modulate both photoreceptor and rod bipolar cell responses. J. Comp. Neurol. 472:13–23, 2004.Keywords
This publication has 47 references indexed in Scilit:
- Neuron‐specific distribution of P2X7 purinergic receptors in the monkey retinaJournal of Comparative Neurology, 2003
- Synaptic localization of NMDA receptor subunits in the rat retinaJournal of Comparative Neurology, 2000
- Localization of metabotropic glutamate receptors mGluR1? and mGluR2/3 in the cat retinaJournal of Comparative Neurology, 1999
- The Cytolytic P 2Z Receptor for Extracellular ATP Identified as a P 2X Receptor (P2X 7 )Science, 1996
- Localization and developmental expression of the NMDA receptor subunit NR2A in the mammalian retinaJournal of Comparative Neurology, 1994
- Immunocytochemical localization of glycine receptors in the mammalian retinaJournal of Comparative Neurology, 1993
- Electron microscopic analysis of the rod pathway of the rat retinaJournal of Comparative Neurology, 1993
- The rod bipolar cell of the mammalian retinaVisual Neuroscience, 1991
- Synaptic connections of rod bipolar cells in the inner plexiform layer of the rabbit retinaJournal of Comparative Neurology, 1990
- Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.Proceedings of the National Academy of Sciences, 1979