ASIC1a-G430C activation by MTS-reagents at neutral pH.

<p><b>A-C</b>. Oocytes expressing G430C were perfused at pH 7.8 (blue line); current was first elicited at pH 5.5 (red line) before returning the extracellular pH 7.8 with amiloride (dashed line). Then, the extracellular pH was set at 7.4 or 7.0, and the oocytes perfused for 40 s. with solutions containing 100 μM (crosshatching red line) of either MTSET (<b>A</b>), MTSPTrEA (<b>B</b>), or MTSES (<b>C</b>); removal of MTS and addition of amiloride were done at pH7.8. A second acidic pulse at pH 5.5 (red line) was performed that included, sequentially, the removal of amiloride, the acidification at pH 5.5 and the re-addition of amiloride (300 μM) at pH 7.8. <b>D</b>. pH-dependence of ASIC1-G430C activation by MTSET (open circles) and MTSPTrEA (filled circles). Values obtained 30s. after addition of the MTS were normalized for the maximal current obtained during the second acidic pulse at pH 5.5. Values on the graph are mean ±SE from 15 to 53 measurements. Dashed lines represent the best fits for the pH dependency.