抄録
In the retina, while it is known that extracellular ATP inhibits ACh release from cholinergic neurons, the types of purinoceptors on the cholinergic neurons have not been examined. We reported that immunoreactivity for P2X2 localized asymmetrically between the ON and OFF pathways in the cholinergic amacrine cells in the mouse retina. In the present study, we recorded the responses to ATP in the cholinergic amacrine cells of the transgenic mouse retina. Both straburst amacrine cells and displaced amacrine cells responded to 100 μM ATP. ATP induced an inward current. However, part of displaced amacrine cells did not respond to 100 μM ATP. Both types of cells did not respond to 100 μM α,β-methylene ATP. Responses to ATP were inhibited by 100 μM PPADS. When cells received GABAergic-IPSP, 100 μM ATP augmented GABAergic IPSP. These results indicate that inhibitory action of ACh released by ATP is mediated by the presynaptic mechanisms. [Jpn J Physiol 54 Suppl:S162 (2004)]
