title: Prostaglandin-induced bicarbonate secretion in the canine stomach: characteristics and evidence for a cholinergic mechanism.
abstract: Using a canine chambered stomach preparation, the effect of topical 16,16-dimethyl prostaglandin E2 (dmPGE2) in neutral solution (150 mN NaCl) on gastric mucosal bicarbonate (HCO-3) secretion was assessed. Compared to control studies in which neutral solution alone bathed the epithelium, dmPGE2 (0.5, 1.0, 2.0, and 4.0 micrograms/ml), when applied to gastric mucosa, significantly increased the output of gastric HCO-3 in a stepwise and dose-related fashion. Accompanying these effects in HCO-3 output were similar increases in sodium, potassium, chloride, and gastric perfusate volume. IN other studies, the effects of intravenous atropine and close intraarterial tetrodotoxin on this PG-induced HCO-3 secretion were evaluated. Both agents completely prevented the stimulation of HCO-3 output induced by dmPGE2 (2 micrograms/ml). It is concluded that dmPGE2, when topically applied to canine gastric epithelium, is a potent stimulant of bicarbonate output that is dose-dependent. The ability of atropine and tetrodotoxin to prevent this secretion suggests that a cholinergic mechanism may be involved and that dmPGE2 mediates its effects on HCO-3 output through acetylcholine release which in turn stimulates cholinergic nerve endings.
mesh_terms: D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology*; D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001639:Bicarbonates / Q000378:metabolism*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009411:Nerve Endings / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000502:physiology*; D011459:Prostaglandins E, Synthetic / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D001639:Bicarbonates; D011459:Prostaglandins E, Synthetic; D013779:Tetrodotoxin; D001285:Atropine; D015064:16,16-Dimethylprostaglandin E2; D000109:Acetylcholine