Fig. 5. Electrophysiological responses (amplitude of contractility) obtained by stimulation of colon tissue circular strips with inhibition of muscarinic, neural, and nicotinic pathways; and expression of nicotinic and muscarinic receptors. Control and infected groups were evaluated in the acute phase (AP; 11 days) and chronic phase (CP; 15 months post-infection [m.p.i]) of Trypanosoma cruzi. Colon fragments were incubated with acetylcholine (ACh; 10 μM), atropine (muscarinic blocker; 1 μM), tetrodotoxin (neuronal blocker; 100nM), d-tubocurarine chloride (nicotinic blocker; 50 μM) methyl ester of N (ω) -nitro-L-arginine (L-NAME, nitric oxide [NO] blocker; 300 μM). (A) ACh + Muscarinic receptor block. (B) Neural block + Muscarinic receptor block. (C) Neural block + Nicotinic receptor block. (D) Neural block + NO block. n = 4 for contraction amplitude. (E and F) The colon tissue expression of proteins of muscarinic type 3 receptor (anti-M3r) and nicotinic alpha 7 receptor (anti-α-7) of the control and the infected groups of the AP and the CP15 m.p.i. were measured by Western blot. β-actin was used as a control protein. n = 5 for Western blot analysis. Statistical analysis: Student’s t tests. Control (○); Infected (●). The symbols (*) represent differences between the groups (control vs infected). The symbols (#) represent differences between the groups infected. P ≤ 0.05. Data presented as mean ± SD.
© J Neurogastroenterol Motil
