title: OFF-cholinergic-pathway-selective localization of P2X2 purinoceptors in the mouse retina.
abstract: It is known that, in the retina, extracellular adenosine triphosphate (ATP) inhibits acetylcholine (ACh) release from cholinergic neurons, but the types of purinoceptors on cholinergic neurons have not been examined. In the present work, we immunohistochemically examined the distribution of the purinoceptors P2X1, P2X2, P2X4, and P2X7 in relation to the cholinergic system of the retina in wild-type mice and transgenic mice expressing green fluorescent protein (GFP). Immunoreactivity for P2X2 was very strong in sublamina a of the inner plexiform layer but very weak in sublamina b of the inner plexiform layer of the retina. Immunoreactivity for P2X2 was colocalized with that for choline acetyltransferase (ChAT). When transgenic mice were treated with the immunotoxin-mediated cell-targeting technology to ablate cholinergic amacrine cells selectively, immunoreactivity for P2X2 and the signals for GFP disappeared in parallel and selectively in the OFF pathway. The distribution of immunoreactivity for P2X1, P2X4, and P2X7 differed from that of ChAT immunoreactivity. The selective distribution of P2X2 purinergic receptors in OFF-type cholinergic amacrine cells indicates that the P2X2 purinergic signaling systems in the ON and OFF pathways of the inner plexiform layer of the mouse retina are functionally different. The distribution of P2X2 purinoceptors may be responsible for the selective regulation of ACh release in the OFF pathway.
authors.affiliation: Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan. mkaneda@sc.itc.keio.ac.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Kaneda
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Ishii
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Morishima
authors.forename: Takumi
authors.initials: T
authors.lastname: Akagi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Shigetada
authors.initials: S
authors.lastname: Nakanishi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hashikawa
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D025042:Amacrine Cells / Q000378:metabolism*; D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D002799:Cholinergic Fibers / Q000378:metabolism*; D003714:Denervation; D049452:Green Fluorescent Proteins; D007150:Immunohistochemistry; D000922:Immunotoxins; D008164:Luminescent Proteins; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D012160:Retina / Q000166:cytology / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D014795:Visual Pathways / Q000166:cytology / Q000378:metabolism*
chemical_list: D000922:Immunotoxins; D008164:Luminescent Proteins; C546402:P2rx2 protein, mouse; C548227:P2rx4 protein, mouse; C546469:P2rx7 protein, mouse; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D049452:Green Fluorescent Proteins; D000255:Adenosine Triphosphate; D002795:Choline O-Acetyltransferase; D011493:Protein Kinase C; D000109:Acetylcholine