Table 1.

The composition of Ringer solutions

	Serosa		Lumen
	Cl−/HCO3− HCO3−-free		Cl−-free	Cl−	SCFA
Cl−	123	123		123
HCO3−	25
Isethionate		25	147	25	122
Isobutyrate					25
SO4−				1	1

Compositions of constituents of all solutions are provided in mM; pH of all Cl⁻-containing solutions was adjusted to 7.4 with HCl, whereas that of Cl⁻-free solutions was adjusted with H₂SO₄. HCO₃⁻-containing solutions were gassed with 95% O₂-5% CO₂; HCO₃⁻-free solutions were gassed with 100% O₂. All solutions contained (in mM) 140.8 Na⁺, 5 glucose, 5.2 K⁺, 0.5 Ca²⁺, and 0.5 Mg²⁺. Of note, the anion isethionate is not a short-chain fatty acid (SCFA) and was used to substitute Cl⁻ and/or HCO₃⁻.