Vagovagal inhibition of motilin-induced phase III contractions by antral acidification in dog stomach.
Gastric acidification at pH 1.0 strongly inhibits the spontaneously occurring and motilin-induced phase III contractions in canine and human stomach. In this study, we examined inhibition by gastric acidification in dogs following gastrojejunostomy, truncal vagotomy, and antrectomy. As a result, gastric acidification with 0.1 N HCl solution at pH 1.0 for 30 min at a rate of 1.0 ml/min significantly inhibited motilin-induced phase III activity to 23.5 +/- 5.9% of the control in the normal intact dogs and to 17.2 +/- 3.4% in the gastrojejunostomized dogs. In the antrectomized dogs, gastric acidification did not significantly inhibit the action of motilin (81.7 +/- 10%), but, in the vagotomized dogs, gastric acidification inhibited the action of motilin to 72.0 +/- 4.9%; the inhibition was much weaker than in the intact and gastrojejunostomized dogs but was significant. The duodenal acidification had no effect at all on the action of motilin (94.6 +/- 12.5%) in the gastrojejunostomized dogs. These findings strongly suggest the existence of a vagovagal reflex in the inhibition of motilin-induced phase III contractions by gastric antral acidification, although the involvement of sympathetic regulation cannot be completely ruled out.
Yamamoto
O
O
Gastrointestinal Research Laboratories, Gunma University, Maebashi, Japan.
Matsunaga
Y
Y
Haga
N
N
Itoh
Z
Z
D000818:Animals; D004285:Dogs; D005744:Gastric Acid / Q000378:metabolism*; D005769:Gastrointestinal Motility; D005774:Gastrostomy; D007582:Jejunostomy; D009037:Motilin / Q000494:pharmacology*; D011706:Pyloric Antrum / Q000378:metabolism* / Q000502:physiology; D012016:Reference Values; D013270:Stomach / Q000187:drug effects*; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*
D009037:Motilin