Localization and Possible Function of P2X Receptors in Normal and Diseased Retinae.
Purines, when present in the extracellular space, can mediate fast neurotransmission in the retina and central nervous system. Over the last decade there has been emerging evidence for the expression of P2X and P2Y receptors in a range of retinal neuronal subtypes. These results have highlighted important roles for purines in modulating specific retinal circuits, including the rod pathway and amacrine cell circuits. Traditionally, synaptic release of adenosine triphosphate (ATP) involves the novel anion vesicular nucleotide transporter, VNUT, which has recently been identified in a single wide-field amacrine cell population. In addition, nontraditional, conductive mechanisms of release have also been described in the retina. In the synapse, the enzymes involved in rapid degradation of purines are present in both plexiform layers of the retina. A role for P2X receptors in retinal diseases has also emerged recently. High concentrations of ATP lead to photoreceptor loss, through mechanisms involving P2X7receptors. In addition, activation of P2X7receptors is associated with activation of the inflammasome, a protein complex important for the release of proinflammatory cytokines. P2X receptors, especially P2X7, are emerging as targets to combat retinal disease.
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Tracy
T
Ho
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Felix P
FP
Aplin
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Andrew I
AI
Jobling
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Joanna A
JA
Phipps
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Robb U
RU
de Iongh
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Ursula
U
Greferath
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Kirstan A
KA
Vessey
Department of Anatomy and Neuroscience, The University of Melbourne , Parkville, Australia .
Erica L
EL
Fletcher
D000818:Animals; D006801:Humans; D058469:Receptors, Purinergic P2X / Q000032:analysis / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*
D058469:Receptors, Purinergic P2X
P2X; purinergic; retina; retinal degeneration; rod pathway