Figure 1.

Capsaicin inhibition of secretagogues-induced intestinal I_scvia a TRPV4-dependent but TRPV1-independent manner.A–C, representative time courses and summary data showing the inhibitory effect of capsaicin (Cap) on carbachol (CCh, 100 μM, n = 6)- or caffeine (Caf, 10 mM, n = 6)-stimulated jejunal I_sc after mucosal (m), serosal (s) addition, and mucosal plus serosal (m+s) addition of capsaicin (30 μM). D–F, representative time courses and summary data showing the inhibitory effect of Cap on CCh (n = 6)- or Caf (n = 6)-stimulated distal colonic I_sc after capsaicin addition as in A–C. G and H, summary data showing the inhibitory effect of capsaicin (Cap, 30 μM) on carbachol (CCh, 100 μM, n = 5)- or caffeine (Caf, 10 mM, n = 5)-stimulated distal colonic I_sc in the absence or the presence of SB705498 (SB, 5 μM) to both sides in WT mice. I and J, summary data showing the inhibitory effect of capsaicin on CCh (n = 7)- or Caf (n = 7)-stimulated jejunal I_sc in TRPV1 KO mice. K and L, representative time courses and summary data showing the inhibitory effect of capsaicin on CCh (n = 5)- or Caf (n = 5)-stimulated distal colonic I_sc in the absence or the presence of HC067047 (HC, 10 μM) to both sides in WT mice. M–O, representative time courses and summary data showing the inhibitory effect of capsaicin on CCh (n = 5)- or Caf (n = 5)-stimulated distal colonic I_sc in TRPV4 KO mice. P and Q, summary data showing the inhibitory effect of capsaicin on CCh (n = 5)- or Caf (n = 5)-stimulated jejunal I_sc in TRPV4 KO mice. Ctrl represents as the control without capsaicin treatment, and m or s in parentheses represents mucosal or serosal addition of capsaicin, respectively. CCh and Caf both add to serosal side. The data are presented as mean ± SD. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001 were performed by Student’s t test. ns, no significant differences. Caf, caffeine; CCh, carbachol; I_sc, short-circuit current; TRPV, transient receptor potential vanilloid.