title: Role of local motility changes in the pathogenesis of duodenal ulcers induced by cysteamine in rats.
abstract: The possible role of local motility in the pathogenesis of duodenal ulcers was investigated in rats using cysteamine. Duodenal motor activity was measured as intraluminal pressure recordings by means of a balloon positioned in the proximal duodenum. Subcutaneous administration of cysteamine (100 mg/kg) produced two linear bandlike lesions in the proximal duodenum within 6 hr. This dose of cysteamine significantly increased gastric acid secretion in acute fistula rats, and decreased duodenal HCO3- secretion caused by acid. During this period, this agent inhibited gastric motility but did produce markedly enhanced contractions in the duodenum. The changes in duodenal motility appeared within 5-10 min and were dose-dependent for cysteamine (10-100 mg/kg). Pretreatment with subcutaneously administered atropine (10 mg/kg), 16,16-dmPGE2 (30 micrograms/kg) or dopamine (10 or 30 mg/kg) significantly reduced the development of duodenal lesions caused by cysteamine, the inhibition being 86.8%, 49.7%, 54.5% or 67.8%, respectively. In the presence of cysteamine, dopamine had minimal effect on both acid and HCO3- secretion, while atropine or 16,16-dmPGE2 markedly inhibited acid secretion or increased HCO3- secretion, respectively. The enhanced duodenal motility induced by cysteamine was blocked partially by atropine and only slightly by 16,16-dmPGE2. Dopamine showed a dose-dependent inhibition on the duodenal hypermotility following cysteamine, and at 30 mg/kg almost completely abolished the development of contractions. These results suggest that abnormal hypermotility in the duodenum may be partly involved in the pathogenesis of cysteamine-induced duodenal ulcers.
mesh_terms: D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D003543:Cysteamine / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004381:Duodenal Ulcer / Q000209:etiology*; D004386:Duodenum; D005745:Gastric Acidity Determination; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007419:Intestinal Secretions / Q000032:analysis / Q000187:drug effects; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D003543:Cysteamine; D001285:Atropine; D015064:16,16-Dimethylprostaglandin E2; D004298:Dopamine