Fig. 4. Electrophysiological responses (amplitude of contractility) were obtained by stimulation of colon tissue circular strips in the presence of acetylcholine (ACh), L-NAME, and L-NAME + ACh. Control and infected groups were evaluated in the acute phase (AP) [11 days] and chronic phase (CP) [3, 7, 12, and 15 months post-infection (m.p.i)] of Trypanosoma cruzi infection. To the colon tissue fragments in an organ bath system was added (A) Acetylcholine (ACh), followed by inhibition with (B) Nω-nitro-L-arginine methyl ester (L-NAME) and then (C) ACh. Statistical analysis: two-way ANOVA and Student–Newman–Keuls. n = 5, for each group, except for control CP12, CP15, and infected CP3 and CP12, n = 4. Control (○); Infected (●). The symbols (*) represent differences in the relation to the group (control vs infected) and the letters (a, b) represent the difference in the frequency, regarding the same group. aDifferent from AP. bDifferent from CP3. P ≤ 0.05. Data presented as mean ± SD. In the schematic drawing next to the graphs, the arrows indicate the ACh time point administration.
© J Neurogastroenterol Motil
