Fluorescein-5-isothiocyanate/analogs & derivatives; Intestinal Absorption/drug effects; Macromolecular Substances/metabolism; Nitric Oxide Donors/metabolism; 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt/metabolism; 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt/pharmacology; Adenosine Triphosphate/metabolism; Animals; Benzoates/administration & dosage; Benzoates/metabolism; Benzoates/pharmacokinetics; Colon/drug effects; Colon/metabolism; Colon/pathology; Dextrans/chemistry; Dextrans/metabolism; Dextrans/pharmacology; Drug Synergism; Fluorescein-5-isothiocyanate/chemistry; Fluorescein-5-isothiocyanate/metabolism; Fluorescein-5-isothiocyanate/pharmacology; Free Radical Scavengers/metabolism; Free Radical Scavengers/pharmacology; Hydrazines/antagonists & inhibitors; Hydrazines/metabolism; Hydrazines/pharmacology; Hydroxyl Radical/metabolism; Imidazoles/administration & dosage; Imidazoles/metabolism; Imidazoles/pharmacokinetics; Intestinal Absorption/physiology; Macromolecular Substances/administration & dosage; Macromolecular Substances/pharmacokinetics; Male; Nitrates/metabolism; Nitric Oxide/metabolism; Nitric Oxide/pharmacology; Nitric Oxide Donors/classification; Nitric Oxide Donors/pharmacology; Nitroso Compounds/metabolism; Nitroso Compounds/pharmacology; Rats; Rats, Wistar; Superoxides/metabolism; Triazenes/metabolism; Triazenes/pharmacology