title: Inhibition of phase III activity by acidifying stomach in vagally denervated and innervated dogs with gastric pouches.
abstract: OBJECTIVE
  Intragastric acidification at pH 1.0 strongly inhibits phase III contractions in the dog, but this mechanism is not well known. We studied the mechanism in conscious dogs.
  
  
  METHODS
  Vagally denervated and innervated gastric pouch dogs were prepared. Force transducers were chronically implanted on the serosa of the pouch, main stomach, and mid-duodenum. The pH of the perfusate was monitored.
  
  
  RESULTS
  Administration of histamine (40 micrograms.kg-1.h-1 intravenously [i.v.]) and instillation of acidic saline at pH 1.0, but not pH 2.0, into the main stomach strongly inhibited the motilin-induced (0.1 microgram/kg i.v.) phase III activity in the main stomach and the innervated pouch but did not influence contractions in the extrinsically denervated pouch. Famotidine completely reversed the histamine-induced inhibition of phase III in the main stomach and Pavlov pouch. Acidification of the pouch itself or duodenum at pH 1.0 did not affect contractions in the main stomach and pouch of either type.
  
  
  CONCLUSIONS
  The mechanism of inhibition of motilin-induced phase III activity by acid in the stomach involves the intact vagovagal reflex, but sympathetic participation is not completely ruled out. The inhibition of motilin-induced phase III activity may originate in the antral mucosa of the stomach.
authors.affiliation: Gastrointestinal Research Laboratories, Gunma University, Maebashi, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Matsunaga
authors.forename: N
authors.initials: N
authors.lastname: Haga
authors.forename: A
authors.initials: A
authors.lastname: Mizumoto
authors.forename: Z
authors.initials: Z
authors.lastname: Itoh
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000818:Animals; D003714:Denervation; D004285:Dogs; D004386:Duodenum / Q000187:drug effects; D015738:Famotidine / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D015391:Gastroplasty / Q000379:methods; D006632:Histamine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007262:Infusions, Intravenous; D009037:Motilin / Q000494:pharmacology; D012016:Reference Values; D013270:Stomach / Q000187:drug effects* / Q000294:innervation; D014630:Vagus Nerve / Q000502:physiology*
chemical_list: D000143:Acids; D009037:Motilin; D015738:Famotidine; D006632:Histamine