Fig. 4.

TGR5 agonism relaxes gallbladder smooth muscle ex vivo. A, Ex vivo tensiometry was performed using gallbladder tissue from female wild-type (WT) (top panels) or Tgr5^−/− mice (lower panels). Gallbladders were precontracted with 1 nm CCK for 20 min, washed, and subsequently treated with either vehicle (DMSO), LCA (10 μm), INT-777 (10 μm), or forskolin (FSK) (2 nm) for 20 min. DMSO, LCA, and INT-777 treatments were followed by a second wash and treatment with forskolin (2 nm) for 20 min to ensure integrity of the tissue. Representative tension tracings are shown with treatment times indicated by arrows. B, Quantification of gallbladder relaxation using tissue derived from WT or Tgr5^−/− mice treated with vehicle (DMSO), LCA, INT-777, or forskolin as in A. Data are the mean ± sem of experiments performed in quadruplicate and are expressed as percent relaxation of CCK-induced contraction. ***, P < 0.001. C, Intracellular cAMP concentrations were measured in gallbladder tissue from WT or Tgr5^−/− mice treated ex vivo with vehicle (DMSO) (open bars) or INT-777 (25 μm) (closed bars) for 15 min. Experiments repeated in male mice produced similar results. Data are the mean ± sem of assays performed six to seven times. *, P < 0.01.