Pharmacological activation mechano-gated K2P channels relaxes CCh and KCl pre-contracted mouse ileum and colon tissues. Top, representative traces showing the time course of the addition of mechano-gated K2P channel activators 30 μM CDC (A1) and 60 μM BL-1249 (B1) to mouse ileum, pre-contracted with 10 μM carbachol (CCh). Scale bars represent 0.4 g (vertical), and 1 min (horizontal). Mean concentration-response relationships in CCh pre-contracted ileum (black circles) and colon (gray triangles) for Cinnamyl 1-3,4-dihydroxy-alpha-cyanocinnamate (CDC) (A2) and the fenamate BL-1249 (B2) are shown below the corresponding traces. All data was fitted with non-linear regression giving predicted IC50's of CDC (8.5 ± 1.0 μM in ileum vs. 18.6 ± 3.5 μM in colon); BL-1249 (13.7 ± 1.4 μM in ileum vs. 60.8 ± 4.2 μM in colon). (A2)
inset, mean normalized relaxation in CCh pre-contracted ileum (black bar) and colon (gray bar) to Zileuton (10 μM). (B2)
inset, mean normalized relaxation in CCh pre-contracted ileum (black bar), and colon (gray bar) to aspirin (100 μM). (C,D) mean normalized relaxation of CCh (C) and KCl (D) pre-contracted ileum (black bars) and colon (gray bars) by Riluzole (100 μM), BL-1249 (30 μM), fluflenamic acid (FFA) (100 μM) and CDC (30 μM). Error bars represent standard deviation (SD). Lower panels, (E1) mean normalized relaxation in ileum to 10 μM BL-1249 in the absence (gray bar) and presence (white bar) of 1 mM barium chloride (Ba2+), (E2) mean normalized relaxation in colon to 30 μM BL-1249 in the absence (black bar) and presence (white bar) of 1 mM barium chloride (Ba2+). All data represents n = 6 animals. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, two-way ANOVA followed by the Bonferroni post-hoc test (A2,B2), unpaired t-test (C,D), paired t-test (E1,E2).