Figure 4

pBQ and NAPQI directly activate TRPV1 from the intracellular side. (A) Single channel recordings from inside-out patches show an increased open state probability of TRPV1 channels during 10 µM pBQ application (b) which is decreased by co-application of 100 nM BCTC (c). Sections a,b,c and d represent episodes of 1 s of the upper trace with an expanded time scale. (B,C,D) Amplitude histograms calculated from 20 s sections of the full trace in Fig. 4A show two peaks for the open states of two channels in the patch and a small closed state peak during application of pBQ (C). Histograms (B and D) display a prominent closed state probability of TRPV1 channels before pBQ treatment (buffer, B) and after pBQ treatment with co-application of BCTC (D). (E) Representative trace for single channel recordings from inside-out patches with increased open state probability of TRPV1 during application of 10 µM NAPQI (b) and decreased open state probability by co-application of 100 nM BCTC (c) Sections a, (b,c) and d represent 1 s episodes of the upper trace with an expanded time scale. (F,G) and (H). Amplitude histograms calculated from 20 s sections of the full trace in Fig. 4E showing two peaks for the open states of two channels in the patch and a small closed state peak during application of NAPQI (G). TRPV1 channels reside predominantly in the closed state before NAPQI treatment (buffer, F) and during co-application of NAPQI and BCTC (H).