Figure 2.
Desensitization of ASIC-1as. a, Representative ASIC currents activated by successive 3-s-long acidic puffs of a pH 6.0 solution at 10 s intervals, showing ASIC desensitization (transient ASIC-1a currents with progressively lower peak amplitudes). b, ASIC current amplitudes as a function of time during repetitive activation of ASICs, normalized to the first evoked IASIC. Desensitization time constant (τD) calculated by fitting to a single-exponential equation was τD = 5.7 ± 0.8 s (n = 6). c, After the desensitization of ASIC currents by three successive 3-s-long acidic puffs of pH 6.0 (10 s interval), recovery was determined by returning the pH of the extracellular solution to 7.4 for different time intervals (from 20 to 120 s) and then applying a test 3-s-long puff at pH 6.0. Recovery was quantified as the ratio between the peak current amplitude in response to the test pH 6.0 puff and the first peak current amplitude before desensitization (control). d, Time course of recovery of ASIC current amplitudes after desensitization, fitted by a sigmoid function: I = 1/[1 + exp((t − τR)/k)]. The time for half-recovery (τR) was 39.5 ± 0.7 s, and the slope k was 10.8 ± 0.7 s (n = 6).