Figure 3.

PcTx1 shifted pH activation of ASIC1a/2a toward lower proton concentrations in CHO cells. (a) Current traces from a single cell showing activation of ASIC1a/2a at various test pHs (pH6.8–5.7) in the absence of PcTx1. (b) Current traces from the same cell as in (a) showing activation of ASIC1a/2a at the same test pHs in the presence of 100 nM PcTx1. (c) Average current responses as a function of test pH in the absence (solid squares) and presence (open circles) of 100 nM PcTx1. Current amplitudes were normalized to that at pH5.7 for each cell in the absence (n = 6) and presence (n = 4) of PcTx1, respectively. The solid and dashed lines are best fits to the data in the absence (pH₅₀ = 6.19) and presence (pH₅₀ = 6.31) of 100 nM PcTx1, respectively. PcTx1 significantly (P < 0.05) shifted the pH activation curve to lower H⁺ concentrations. The conditioning pH was 7.1 for all the experiments in Fig. 3.