Localization and activity of nitric oxide synthases in the gastrointestinal tract of Trypanosoma cruzi-infected mice

Chagas' disease, caused by the protozoan parasite, Trypanosoma cruzi, is as sociated with gastrointestinal abnormalities. Since nitric oxide (NO) has b een shown to be a factor influencing intestinal function we evaluated the d istributions and activities of the NO synthase (NOS) isoforms, in the gut o f mice infected with T. cruzi. Ca2+-dependent (NOS1/NOS3) activity was decr eased, whereas Ca2+-independent (NOS2) activity was increased in infected m ice. NOS2-immunoreactivity was demonstrated in cells within the muscle laye rs and epithelium in infected mice and NOS1 immunoreactivity was seen in ne rve structures. These data indicate that alterations in the NO-system may b e important in the pathogenesis of the gastrointestinal manifestations in C hagas' disease. (C) 1999 Elsevier Science B.V. All rights reserved.