Histological, biochemical and pharmacological characterization of the gastric muscular layer in Chagas disease.
OBJECTIVE
To assess in vitro the correlation between the number of neurons and the sensitivity to cholinergic drugs and acetylcholinesterase activity in chagasic patients.


METHODS
A 3 x 1 cm strip of the muscle layer of the anterior part of the stomach, always close to the angular incisure, was removed from 10 chronic chagasic patients (6 men) submitted to megaesophagus or megacolon surgery and from 10 non-chagasic patients (4 men) submitted to other types of surgery (control group), aged on average 52.3 and 50.1 years, respectively, for histological and pharmacological studies. The action of cholinergic drugs was investigated in isolated preparations according to the superfusion method of Ferreira and Costa, and acetylcholinesterase activity was determined by the method of Ellman. For neuron count, the strips were cut into 8 µm sections according to the method standardized by Alcântara.


RESULTS
There was a difference in number of neurons between the chagasic (5,6) and control (7,3) groups. Acetylcholinesterase activity, in moles of hydrolyzed substrate per minute per gram tissue, was reduced in chagasic patients (4,32) compared to the controls (7,30). No hypersensitivity of the gastric musculature to cholinergic drugs was detected, with a reduced maximum response to carbachol and betanechol in the chagasic group.


CONCLUSIONS
The reduction of neurons in the myenteric plexus of the stomach of chronic chagasic patients can be demonstrated even in the absence of clinical chagasic gastropathy. The hypersensitivity of the gastric musculature to cholinergic drugs probably depends on intense denervation. The reduced acetylcholinesterase activity demonstrates the involvement of the cholinergic innervation in the stomach of chronic chagasic patients. There was no correlation between number of neurons, sensitivity to cholinergic drugs and acetylcholinesterase activity in the gastric musculature of chagasic and non-chagasic patients.
Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
Wagner
W
Carlucci
Reginaldo
R
Ceneviva
Sérgio Henrique
SH
Ferreira
Orlando Castro de
OC
Silva
D000109:Acetylcholine / Q000494:pharmacology; D000110:Acetylcholinesterase / Q000378:metabolism*; D000328:Adult; D002217:Carbachol / Q000494:pharmacology; D016022:Case-Control Studies; D002452:Cell Count; D014355:Chagas Disease / Q000188:drug therapy* / Q000201:enzymology; D018678:Cholinergic Agents / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology; D004931:Esophageal Achalasia / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology / Q000294:innervation*; D009197:Myenteric Plexus / Q000473:pathology*; D009474:Neurons / Q000166:cytology; D013270:Stomach / Q000187:drug effects / Q000201:enzymology / Q000294:innervation*
D018678:Cholinergic Agents; D018679:Cholinergic Agonists; D002217:Carbachol; D000110:Acetylcholinesterase; D000109:Acetylcholine