Background-Antral motility and the hormone cholecystokinin (CCK) are m
ajor determinants of the rate of gastric emptying. The relation betwee
n CCK and antral neurons in regulating gastric emptying is uncertain.
Benzalkonium chloride (BAG) causes selective lesions in gut myenteric
neurons after serosal application Aim-To develop a model of antral den
ervation using BAC to enable the study of the relation between CCK and
antral neurons in regulating gastric emptying. Methods-BAC, vehicle o
r the afferent neurotoxin capsaicin were applied to the serosal surfac
e of the rat antrum or corpus; neurochemical markers of intrinsic and
afferent neurons were detected by using immunohistochemistry and radio
immunoassay. Gastric retention of solids was determined after fasting,
and emptying of liquids was measured in rats with gastric fistulae. R
esults-In BAC treated rats radioimmunoassay of tissue extracts reveale
d a dose related specific loss of gastrin releasing peptide, substance
P, vasoactive intestinal polypeptide immunoreactivities from the trea
ted region, and immunohistochemistry revealed loss of the neuronal mar
ker PGP 9.5 and the afferent neuropeptide calcitonin gene related pept
ide (CGRP). Adjacent untreated regions were unaffected by BAG, with th
e exception that CGRP was depleted in both corpus and antrum after ant
ral treatment. After antral BAC treatment fasted rats retained solids
for over 48 hours. Moreover, in antrally denervated rats with gastric
fistulae, the emptying of saline, acid and peptone was delayed substan
tially. The CCK dependent inhibition of gastric emptying of peptone wa
s preserved after antral treatment with BAG. Conclusions-Serosal BAC c
auses lesions in the innervation of the treated region of the stomach.
The innervation of the antrum is essential for normal emptying of bot
h liquids and solids, but the inhibition of gastric emptying produced
by CCK is not dependent on antral neurons.