Figure 7. Strong depolarization changed the kinetics of ATP responses by a mechanism that was not dependent on extracellular Ca²⁺.

The data shown in A are the averaged, normalized current to ATP (10 μM) obtained when ATP was applied to cells (irrespective of capsaicin sensitivity) in the absence of any other treatment compared to the current obtained in cells that had been exposed to a 2–5 min conditioning step to +40 mV and then repolarized to −60 mV 2 min prior to ATP application. The data in C are equivalent to the data in A except that the conditioning pre-pulse was applied in the absence of extracellular Ca²⁺. The data in B and D are plots of probability values obtained from unpaired t tests applied at 10 ms intervals comparing the current traces in A and C, respectively. V_h was −60 mV. The horizontal dashed lines in B and D indicate a value of P = 0.05.