Figure 1. Effect of Cl⁻ withdrawal from the bath solution on unidirectional and net Na⁺ fluxes in rabbit descending colon.

Both the solutions used for the above study contained equimolar amounts of isethionate in place of Cl⁻. Basal as well as butyrate-stimulated Na⁺ absorption took place even in the absence of Cl⁻. Butyrate induced a significant increase in J_Na,net (*P = 0.006) and J_Na,sm (**P = 0.002) compared with basal values.