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Target Concepts:
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Query: UMLS:C0017168 (
gastroesophageal reflux disease
)
11,783
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Cisapride and metoclopramide are used clinically in the treatment of gastro-
oesophageal reflux
disease and also in a variety of motility disorders of the gastrointestinal tract. Their prokinetic effect is thought to be due to the augmentation of acetylcholine release from the myenteric plexus, an effect likely to be mediated through the stimulation of
5-HT4
receptors. The role of
5-HT4
receptors in the control of intestinal motility in man and animals is not clear, therefore we have investigated their role in the control of small intestinal transit in the rat. Radioactive microspheres were administered into the proximal duodenum of fasted conscious rats through an indwelling cannula. The extent of small intestinal transit was examined by determining the distribution of the microspheres within the intestine. Following i.p. injection small intestinal transit was inhibited (78%) by atropine (3 mg/kg), suggesting the presence of a basal cholinergic influence. Furthermore, in the presence of p-amino clonidine intestinal transit was stimulated (126%) by bethanechol (3 mg/kg). The 5-HT4 receptor agonists cisapride (1.0 mg/kg) and zacopride (1.0 mg/kg) failed to increase small intestinal transit. The 5-HT4 receptor selective antagonist GR125487 (1 mg/kg) was also without effect. These data suggest that
5-HT4
receptors are not involved in the control of small intestinal transit in the fasted conscious rat.
...
PMID:5-HT4 receptors are not involved in the control of small intestinal transit in the fasted conscious rat. 869 80
Tegaserod, a
5-HT4
partial agonist, was shown to reduce esophageal acid exposure in patients with
gastroesophageal reflux disease
; however, its mechanism of action is poorly understood. Therefore, we have examined the effect of tegaserod on luminal bicarbonate and mucin secretion in the isolated perfused pig esophagus. We also studied its role in esophageal protection using SMG-bearing pig esophagus in comparison to the rabbit esophagus, which is devoid of them. The tissues were mounted in Ussing chambers, and acid injury was replicated by exposing the lumen to acid (pH 1.6) or acid/pepsin (pH 2.5). In pig esophagus, tegaserod increased bicarbonate secretion, but had no effect on basal mucin secretion. In Ussing chambers, tegaserod reduced injury to pig, but not rabbit esophagus exposed to acid (pH 2.5) plus pepsin. These results indicate that tegaserod stimulates SMG bicarbonate secretion, an effect that likely accounts for the observed protection against acid-pepsin injury to pig, but not rabbit, esophagus.
...
PMID:The effect of tegaserod on esophageal submucosal glands bicarbonate and mucin secretion. 1827 Aug 37
Serotonin 5-hydroxytryptamine 4(
5-HT4
) receptor agonists have been widely prescribed as a prokinetics drug for patients with gastro-
esophageal reflux disease
and functional dyspepsia. QX100626, one of the 5-HT4 receptor agonists, has been studied as a promising agent for this clinical use. The objective of the present study was to identify possible target organs of toxicity and propose a non-toxic dose of QX100626 for clinical usage. After single lethal dose oral and intravenous testing in rodents, some signs indicative of adverse CNS effects were observed. The minimum toxic dose of QX100626 for a single oral administration for dogs was 90.0mg/kgb.w., and the severe toxic dose was more than 300mg/kgb.w. The No Observed Adverse Effect Level (NOAEL) of QX100626 by daily oral administration for rats and dogs was 20mg/kg and 10mg/kg, respectively, whereas the minimum toxic dosages were 67 and 30mg/kg, respectively. All of the adverse effects suggested that kidney, digestive tract, as well as nervous, hematological, and respiratory systems might be the target organs of toxicity for humans induced by QX100626. The compound could be a safe alternative to other existing prokinetic agents for the treatment of functional bowel disorders.
...
PMID:Acute and subchronic toxicities of QX100626, a 5-HT4 receptor agonist, in rodents and Beagle dogs. 2510 57