Figure 5.

Capsaicin promotion of jejunal Na⁺absorption by rather blocking TRPV4 channels than activating TRPV1 channels.A and B, representative time courses and summary data showing the effect of capsaicin (Cap, 30 μM, n = 5) on glucose-induced jejunal I_sc after its serosal (s) addition or serosal plus mucosal (s+m) addition in WT mice. C and D, summary data showing the effect of SB705498 (SB, 5 μM, n = 5) on glucose-induced jejunal I_sc and the effect of Cap on the I_sc (n = 5) in the absence or the presence of SB in WT mice. E and F, representative time courses and summary data showing the effect of Cap on glucose-induced jejunal I_sc (n = 5) after its serosal (s) addition or serosal plus mucosal (s+m) addition in TRTPV4 KO mice. G, representative time courses and summary data comparing the glucose-induced jejunal I_sc (n = 5) between WT mice and TRPV4 KO mice. H and I, summary data comparing the effect of Cap on glucose-induced jejunal I_sc (n = 5) between WT mice and TRPV4 KO mice after its serosal (s) addition or serosal plus mucosal (s+m) addition. The data are presented as mean ± SD. ∗p < 0.05 and ∗∗p < 0.01 were performed by Student’s t test. ns, no significant differences. I_sc, short-circuit current; TRPV, transient receptor potential vanilloid.