Can bile salts affect the contractile oesophageal activity associated with gastroesophageal reflux disease?

Table 1 List of studies dealing with the impacts of bile salts on smooth muscle activity

Ref.	Bile salts	Receptor	Impacts on motility	Sample
Lavoie et al[37]	CDC, 50-100 μM; LCA, 10 μM	TGR5	Reduction of intracellular calcium levels and rhythmic discharge of intracellular Ca2+, stimulating relaxation and filling of gallbladder smooth muscle	Gallbladder
Poole et al[25]	DCA, 1-100 μM	TGR5	Rapid and sustained inhibition of spontaneous phasic activity by a neurogenic, cholinergic and nitrergic mechanism	Ileum and colon
Alemi et al[34]	DCA, 100 μM	TGR5	Inhibition of colon longitudinal muscle contractility by TGR5 activation in inhibitory motoneurons and nitric oxide release	Colon
Rajagopal et al[38]	OA, 10 μM	TGR5	Relaxation of gastric smooth mediated through inhibition of RhoA/Rho kinase pathway leading to stimulation of MLCP activity and MLC20 dephosphorylation	Gastric muscle cells
Renga et al[39]	CDCA, CA, and LCA (10-8-10-4 M)	TGR5	Vasodilation caused by LCA was GPBAR1-dependent and abolished by 5’-cholanic acid, a TGR5 antagonist	Aortic rings
Li et al[40]	LCA, 10 μM, INT-777	TGR5	Increased cAMP concentrations and smooth muscle relaxation in a TGR5-dependent manner	Gallbladder
Gadelha et al[19]	TDCA (2 mmol/L)		Exposure of the oesophageal lumen to TDCA at pH 7.4 or 1 decreased the responsiveness of oesophageal preparations to KCL	Oesophagus
Chang et al[41]	DCA (0.1-100 μM), UDCA (0.1-100 μM), SBI-115 (100 μM)	TGR5	TGR5 inhibition decreased ERK phosphorylation and led to decreases in contractility, phosphorylated MLC and total MLC	Ileum

LCA: Lithocholic acid; CDC: Tauro-chenodeoxycholate; TGR5: Takeda G protein-coupled bile acid receptor 5; DCA: Deoxycholic acid; OA: Oleanolic acid; MLCP: Myosin light chain phosphatase; MLC: Myosin light chain; CDCA: Chenodeoxycholic acid; CA: Cholic acid; GPBAR1: G protein-coupled bile acid receptor 1; TDCA: Tauro-deoxycholic acid; UDCA: Ursodeoxycholic acid; ERK: Extracellular signal-regulated kinase.