Effect of GSNO or GDNF on the paracellular permeability of mouse and human ileal resections. GSNO or GDNF decreased the passage of 51Cr-EDTA through a 4.9-mm2 ileal mucosal surface from either mice (n = 5 or 6) (A) or humans (n = 4) (B) over 120 min. (C) Infection did not alter the permeability of ileal resections from infected mice (n = 5 or 6 pooled replicates from two animals). Ussing chamber experiments were run for 120 min; samples (300 μl) were collected at 0, 60, and 120 min. Data are the means with SD from two-way ANOVA, followed by Tukey’s (A and B) or Bonferroni’s (C) multiple-comparison test. *, P < 0.05; **, P < 0.01; ***, P < 0.001.