Extracellular ATP also induces increases in extracellular H+ fluxes from the end feet of isolated Müller cells and the inner plexiform layer in retinal slices that are reduced by PPADS and suramin.

<p>(A) An isolated Müller cell with an H+-selective microelectrode positioned by the end foot of the cell; scale bar, 20 μm. (B) A representative trace showing the increase in H+ flux measured from the end foot of a Müller cell in response to application of 100 μM ATP. (C) Mean responses of isolated Müller cells to 100 μM ATP; N = 9, asterisk denotes background control taken 200 μm above the cell. (D) Retinal slice with red box highlighting the inner plexiform layer (IPL). (E) A representative trace showing the response observed to application of 100 μM ATP from a self-referencing H+-selective microelectrode from a retinal slice when the microelectrode was positioned just above the IPL; asterisk indicates a background control reading taken 600 μm above the retinal slice. (F) Mean data from two populations; ATP induced a significant increase in H+ flux that was significantly smaller in the presence of suramin and PPADS (N = 6) than it did in normal Ringer’s solution (N = 6). The data from the two populations are separated by the gap on the x-axis and were compared via an unpaired 2-way t test.