title: Functional evidence linking potassium channels and afferent nerve-mediated mucosal protection in rat stomach.
abstract: Adenosine triphosphate-dependent potassium (K+ATP) channels in several types of vascular smooth muscles mediate the vasodilation induced by calcitonin gene-related peptide (CGRP). Upon stimulation, primary afferent nerve terminals in the gastric mucosa release CGRP which mediates a protective hyperemia. We tested the hypothesis that a potassium channel blocker aggravates gastric mucosal injury by impairing afferent nerve-mediated hyperemia in the gastric mucosa. Rats were treated with K+ATP channel blocker, glybenclamide (20 mg/kg intravenously). Intragastric added ethanol (0.15 N HCl, 15% ethanol) and intragastric capsaicin (160 microM) were also administered. Glybenclamide aggravated the acidified ethanol-induced mucosal injury, and attenuated the mucosal hyperemia (hydrogen gas clearance) induced by intragastric acidified ethanol and intragastric capsaicin. These findings suggest for the first time that K+ATP channels modulate primary afferent nerve-mediated mucosal defense mechanisms in the gastric mucosa.
authors.affiliation: First Department of Internal Medicine, Nagoya City University School of Medicine, Nagoya, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Iwata
authors.forename: A
authors.initials: A
authors.lastname: Koo
authors.forename: M
authors.initials: M
authors.lastname: Itoh
authors.forename: K
authors.initials: K
authors.lastname: Lam
authors.forename: J W
authors.initials: JW
authors.lastname: Leung
authors.forename: F W
authors.initials: FW
authors.lastname: Leung
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000008:administration & dosage; D000431:Ethanol / Q000008:administration & dosage; D005744:Gastric Acid; D005753:Gastric Mucosa / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D005905:Glyburide / Q000494:pharmacology; D006940:Hyperemia / Q000139:chemically induced; D008297:Male; D009475:Neurons, Afferent / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015221:Potassium Channels; D000431:Ethanol; D002211:Capsaicin; D005905:Glyburide