Cholinergic innervation of the lower esophageal sphincter in Chagas' disease.

1. The effect of 12 micrograms/kg iv atropine on the lower esophageal sphincter (LES) pressure was studied by continuous perfusion manometry in 14 Chagasic patients, 9 controls, and 3 patients with achalasia, and the effect of 3 ml iv saline was studied in 7 Chagasic patients. 2. Resting LES pressure did not differ between Chagasic patients (11.5 +/- 4.1 mmHg) and controls (15.9 +/- 4.9 mmHg, P greater than 0.05). 3. Atropine caused a significant decrease in LES pressure in both Chagasics and controls, but the reduction in controls was significantly greater (56%) than in Chagasics (25%). 4. Saline did not change the LES pressure of Chagasics. Atropine caused a similar reduction of LES pressure in achalasia patients (49%) and in controls (56%). 5. These results suggest that the cholinergic excitatory nerves are impaired in Chagas' disease, but not in achalasia, where they were either normal or only minimally impaired.