Neutral substitutions at the acidic pocket do not alter diminazene block.

<p>(A) Cartoon representation of the acidic pocket of cASIC1 (PBD 4NYK). (B) Diminazene dose response curves for wild type ASIC1a and the 6NQ (E219Q/D237N/E238Q/D345N/D349N/D407N) mutant. Whole-cell currents were evoked by a change in extracellular pH from 8.0 to 6.5. The relative response represents the ratio of the pH-elicited peak current after diminazene to the pH-elicited peak current before diminazene. Diminazene IC₅₀ for ASIC1a was 2.42 μM (CI 1.56–3.75 μM, n = 10–14) and for the 6NQ mutant was 2.03 μM (CI 0.88–5.31 μM, n = 10–21).