Effects of sulfasalazine, 5-ASA, and sulfapyridine on toxin A-induced colonic luminal fluid accumulation and MPO activity. Sulfasalazine was administered in the drinking water at a dose of 100 mg/kg·day for 5 days. 5-ASA and sulfapyridine were administered as pretreatments for 30 minutes before toxin A was injected into isolated colonic segments. (a) Toxin A stimulation of colonic luminal fluid accumulation and the inhibition of this effect by chronic treatment with sulfasalazine or acute treatment with 5-ASA or sulfapyridine. (b) Toxin A stimulation of colonic MPO activity and the inhibition of this effect by chronic treatment with sulfasalazine or acute treatment with 5-ASA or sulfapyridine. * versus no treatment; ** versus no treatment; **** versus no treatment; #### versus toxin A.
