Fig. 6: Exendin 9–39 noncompetitively inhibits CAP-induced TRPV1 activation by binding to the extracellular side in CHO K1 cells expressing human TRPV1. | Experimental & Molecular Medicine

Fig. 6: Exendin 9–39 noncompetitively inhibits CAP-induced TRPV1 activation by binding to the extracellular side in CHO K1 cells expressing human TRPV1.

From: GLP-1 and its derived peptides mediate pain relief through direct TRPV1 inhibition without affecting thermoregulation

Fig. 6

a Currents evoked by 100 nM CAP were partially blocked by sequential application of 10 and 20 nM BCTC (left). The remaining currents between the arrows were CAP-induced currents inhibited by BCTC. Summary analysis of the inward currents reduced by BCTC alone (mean ± S.E.M.). Two-tailed unpaired t test (ns, not significant). b Currents evoked by 100 nM CAP were partially blocked by the sequential application of 10 nM BCTC and 100 nM exendin 9–39 (Exe 9–39). The remaining currents between the arrows were CAP-induced currents inhibited by BCTC or exendin 9–39. Summary of inward currents reduced by BCTC alone and BCTC followed by exendin 9–39 (mean ± S.E.M.). Two-tailed unpaired t test (***p < 0.001). c Representative traces from single-channel recordings of TPRV1 channels in the cell-attached configuration. The cells were held at −60 mV. Exendin 9–39 (100 nM) was delivered via either the external (intracellular) or internal (extracellular) solution in the presence of 10 nM CAP externally. c closed state, o open state. d Schematic illustration of cell-attached patch recordings. e Average single-channel open time (left) and open probability (right) (mean ± S.E.M.). One-way ANOVA followed by Dunnett’s multiple comparison test (***p < 0.001, compared with no exendin 9–39). f Representative traces from single-channel recordings of TPRV1 channels in the inside-out configuration. The cells were held at −60 mV. Exendin 9–39 (100 nM) was delivered via either the external (intracellular) or internal (extracellular) solution in the presence of 10 nM CAP externally. c closed state, o open state. g Schematic of inside-out patch recordings. h Average single-channel open time (left) and open probability (right) (mean ± S.E.M.). One-way ANOVA followed by Dunnett’s multiple comparison test was used (**p < 0.01, compared with no exendin 9–39). ANOVA analysis of variance, BCTC N-(4-tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl) tetrahydropyrazine-1(2H)-carboxamide, CAP capsaicin, CHO K1 Chinese hamster ovary, S.E.M. standard error of the mean, TRPV1 transient receptor potential vanilloid 1.

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