Subunit Specificity of Agmatine (AGM) and Arcaine (ARC) in CHO Cells Transfected with One or Two Different ASIC Subunits. (A, B) Representative traces showing the response of AGM (1 mM) or ARC (1 mM) on CHO cells transfected with one (A) or two (B) different ASIC subunits. (C, D) Polled data as shown in (A, B). AGM (1 mM) and ARC (1 mM) directly activate ASIC3 homomeric channels (A, C) and heteromeric ASIC3 + 1b channels (B, D) but not ASIC1a nor ASIC1b nor ASIC2a homomeric channels (A, C), nor heteromeric ASIC3 + 1a, ASIC3 + 2a, ASIC3 + 2b channels (B, D) at the neutral pH (pH = 7.4). Data are means ± S.E.M. n = 3-5. **p < 0.001 vs. baseline level.