Inflammatory soup, but not singly applied inflammatory mediators, potentiates the NaN/Nav1.9 current. (A) Effects of BK (1 μM), PGE2 (2 μM), GTPγ-S (500 μM), and inflammatory soup (50 nM BK, 500 nM PGE2, 1 μM His, 500 nM NE, 2 μM ATP) on TTX-R Na⁺ currents evoked by 50-ms depolarizing voltage steps from −100 to −50 mV. Control recordings on the left represent the average of three consecutive sweeps recorded either 2 min after patch rupturing (GTPγ-S) or immediately before drug application (e.g., BK, PGE2, and inflammatory soup). (right) Currents were evoked every 5 s. For clarity sake, only one sweep every 10 s (BK, PGE2, and inflammatory soup, 26 sweeps) or 25 s (GTPγ-S, 23 sweeps) is shown. (B) Mean NaN/Nav1.9 currents evoked at −50 mV before (black bar) and after (white bar) exposure to mediators or inflammatory soup (IS), as indicated. For comparison, increase in NaN/Nav1.9 induced by dialysis of fluoride or GTPγ-S is also shown. ***, P < 0.001, paired t test. The inset compares averaged time course of NaN/Nav1.9 current in neurons exposed (filled circles, n = 7) or not (open circles, n = 12) to the inflammatory soup. Currents were evoked as in A. The arrow indicates the start of the application of the inflammatory soup. (C) Potentiation of the capsaicin-induced TRPV1 inward current recorded at −80 mV by 1 μM BK. ***, P < 0.001, paired t test. Recordings made using the intracellular solution 3 (Table I; 130 mM CsCl, 0 mM CsF, 0 mM KCl).