Nicotine has no effect on rat gastric mucosal prostaglandin generation in vitro

Previous studies have shown that cigarette smoking depresses prostaglandin generation by human gastric mucosa, but the component of smoke that is responsible for that action is not known. To investigate whether nicotine has a direct effect on gastric mucosal prostaglandin generation, we performed the following study. Eight rats were sacrificed and the stomachs removed. Using a biopsy forceps, small pieces of gastric mucosa were resected and placed in incubation vials containing either buffered Krebs solution alone (control), Krebs solution plus indomethacin (5 micrograms/ml), or Krebs solution plus one of several concentrations of nicotine ditartrate (10, 100, 500, 1000 ng/ml). The nicotine concentrations we used ranged below and above the plasma nicotine concentrations of smokers shortly after smoking cigarettes. Three separate incubations of gastric mucosa were performed per experimental group from each animal. After 30 min of incubation, prostaglandin E2 and 6-keto-prostaglandin F1 alpha concentrations in the incubation medium were measured by radioimmunoassay. We found that nicotine at any concentration tested had no effect on the generation of prostaglandin E2 and 6-keto-prostaglandin F1 alpha by rat gastric mucosa. Thus, this study indicates that, if nicotine is involved in the depression of prostaglandin generation in the gastric mucosa of smokers, its role is an indirect one and not by direct action on the gastric mucosa.