title: Roles of ATP sensitive potassium channel in modulating gastric tone and accommodation in dogs.
abstract: OBJECTIVE
  The ATP sensitive potassium (KATP) channel plays an important role in the regulation of resting membrane potential and membrane excitability. The role of the KATPchannel in modulating gastric motility is unclear. The aim of this study was to investigate the role and mechanism of the KATPchannel in modulating gastric tone and accommodation in dogs.
  
  
  METHODS
  Gastric volume under a constant pressure reflecting gastric tone was measured using a barostat device in dogs equipped with a gastric cannula. Gastric accommodation was evaluated by the difference in gastric volume before and after a liquid meal. The roles of cholinergic and nitrergic pathways in the inhibitory effect of pinacidil (a KATPopener) were assessed.
  
  
  RESULTS
  1) Pinacidil dose-dependently decreased gastric tone at a dosage of 30 (p = 0.628), 100 (p = 0.013) and 300 μg kg-1(p < 0.001). 2) Glibenclamide, a KATPblocker, completely blocked the inhibitory effect of pinacidil on gastric tone. 3) Atropine did not block the inhibitory effect of pinacidil on gastric tone but Nω-Nitro-L-arginine methyl ester markedly attenuated the inhibitory effect of pinacidil (p = 0.004). 4) Glibenclamide significantly reduced gastric accommodation (p < 0.001) while pinacidil had no effects on gastric accommodation. 5) Glibenclamide significantly reduced nitric oxide donor sodium nitroprusside-induced gastric relaxation.
  
  
  CONCLUSIONS
  These findings indicate that the KATPchannel plays an important role in modulating gastric tone and accommodation in dogs. The inhibitory effect of pinacidil on gastric tone was through the nitrergic pathway as well as acting directly on smooth muscle cells.
authors.affiliation: a Veterans Research and Education Foundation, VA Medical Center , Oklahoma City , OK , USA.|b Division of Gastroenterology and Hepatology , Johns Hopkins University , Baltimore , MD , USA.
authors.forename: Shiying
authors.initials: S
authors.lastname: Li
authors.affiliation: a Veterans Research and Education Foundation, VA Medical Center , Oklahoma City , OK , USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Lei
authors.affiliation: a Veterans Research and Education Foundation, VA Medical Center , Oklahoma City , OK , USA.|b Division of Gastroenterology and Hepatology , Johns Hopkins University , Baltimore , MD , USA.
authors.forename: Jiande Dz
authors.initials: JD
authors.lastname: Chen
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects*; D005905:Glyburide / Q000008:administration & dosage*; D054086:KATP Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects; D020110:Pinacidil / Q000008:administration & dosage*; D013270:Stomach / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects
chemical_list: D054086:KATP Channels; D020110:Pinacidil; D005905:Glyburide
keywords: ATP sensitive; Gastric tone; functional-disorders; gastroduodenal-basic; motility; potassium channel