Cholinergic effects on human gastric motility.
BACKGROUND
Cholinergic regulation of chronotropic (frequency) and inotropic (force) aspects of antral contractility and how these impact on gastric emptying are not well delineated.


OBJECTIVE
To determine the effects of cholinergic stimulation and inhibition on myoelectric, contractile, and emptying parameters of gastric motility.


METHODS
Ten normal subjects underwent three studies each, using simultaneous electrogastrography (EGG), antroduodenal manometry, and gastric emptying with dynamic antral scintigraphy (DAS). After 30 minutes of baseline fasting manometry and EGG, subjects received saline intravenously, atropine (0.6 mg then 0.25 mg/hour intravenously), or bethanechol (5 mg subcutaneously). This was followed by another 30 minutes' recording and by three hours of postprandial recording after ingestion of a technetium-99m labelled solid meal.


RESULTS
During fasting, atropine decreased, whereas bethanechol increased, the antral manometric motility index and EGG power. Postprandially, atropine decreased the amplitude of antral contractions by DAS, decreased the postprandial antral manometric motility index, and slowed gastric emptying. Atropine caused a slight increase in postprandial frequency of antral contractions by DAS and gastric myoelectrical activity by EGG. Bethanechol slightly increased the amplitude, but slightly decreased the frequency of antral contractions by DAS and decreased the frequency of gastric myoelectrical activity by EGG, with no significant increase in the motility index or gastric emptying.


CONCLUSIONS
Cholinergic antagonism with atropine reduces antral contractility and slows gastric emptying. Cholinergic stimulation with bethanechol increases antral contractility, but decreases the frequency of antral contractions, without altering the antral motility index or gastric emptying.
Parkman
H P
HP
Gastroenterology Section, Department of Medicine, Temple University Hospital, Philadelphia, Pennsylvania, USA.
Trate
D M
DM
Knight
L C
LC
Brown
K L
KL
Maurer
A H
AH
Fisher
R S
RS
D000328:Adult; D001285:Atropine / Q000494:pharmacology*; D018723:Bethanechol / Q000494:pharmacology*; D004386:Duodenum / Q000502:physiology; D004594:Electrophysiology; D005746:Gastric Emptying / Q000187:drug effects*; D006801:Humans; D008297:Male; D008365:Manometry; D018721:Muscarinic Agonists / Q000494:pharmacology*; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D019518:Postprandial Period / Q000502:physiology; D011706:Pyloric Antrum / Q000502:physiology; D011877:Radionuclide Imaging; D013270:Stomach / Q000000981:diagnostic imaging
D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D018723:Bethanechol; D001285:Atropine