N. Imeryuz et al., GLUCAGON-LIKE PEPTIDE-1 INHIBITS GASTRIC-EMPTYING VIA VAGAL AFFERENT-MEDIATED CENTRAL MECHANISMS, American journal of physiology: Gastrointestinal and liver physiology, 36(4), 1997, pp. 920-927
Exogenous administration of glucagon-like peptide-1-(7-36) amide (GLP-
1), an insulinotropic hormone, inhibits gastric emptying and acid secr
etion in humans. The role of GLP-1 as a regulator of gastric function
is elusive. In gastric fistula rats, vagal afferent denervation and pe
ripheral administration of the GLP-1 receptor antagonist exendin-(9-39
) amide enhanced emptying of a glucose meal, whereas intracerebroventr
icular exendin was ineffective. The rate of saline emptying was attenu
ated by peripheral as well as by central administration of GLP-1, and
pretreatment with exendin by the respective routes reversed the inhibi
tion by GLP-1. Vagal afferent denervation abolished the central and pe
ripheral action of GLP-1 on gastric emptying. Neither peripheral choli
nergic nor adrenergic blockade altered the delay of methyl cellulose m
eal emptying by intracisternal GLP-1 injection. Acid secretion in cons
cious pylorus-ligated rats was inhibited by intracisternal GLP-1 admin
istration, whereas systemic GLP-1 was ineffective. These results suppo
rt the notion that GLP-1 receptors participate in the central and peri
pheral regulation of gastric function. Furthermore, vagal afferent ner
ves mediate the inhibitory action of GLP-1 on gastric motor function.
GLP-1 may be a candidate brain-gut peptide that acts as a physiologica
l modulator of gastric function.