Figure 9.

Conductance and block of ASIC1 channels by guanidinium. (A) I-V relationships with NaCl replaced in part or in full by guanidinium·Cl, in the nominal absence of Ca²⁺. Currents were normalized to values obtained at V_m = −100 mV with 110 mM NaCl (I₀). Data represent means ± SEM for 8–15 measurements. (B) Chord conductance as a function of [guanidinium⁺] at constant [Na⁺] + [guanidinium⁺]. Data represent means ± SEM for 5–15 measurements and were fit by Eq. 3 (see Materials and methods), which yielded a best fit values of G_guan,max = 0.33 and K_guan = 2.2 mM.