Effect of nicotine on gastric mucosal blood flow and acid secretion.

The effects of an intravenous infusion of nicotine at a dose of 2 . 5, 5 . 0, 7 . 5, or 10 . 0 micrograms kg-1h-1 on pentagastrin-stimulated gastric mucosal blood flow and acid secretion were investigated in eight healthy male non-smokers. Each dose was tested in two males. Gastric neutral red clearance served as a measure of mucosal blood flow. Nicotine reduced volume secretion, acid secretion, and neutral red clearance in a dose dependent manner. In five healthy male smokers smoking of five cigarettes per two hours induced similar changes to the intravenous infusion of 5 micrograms kg-1h-1 nicotine. As volume secretion was inhibited more than neutral red clearance, it is concluded that nicotine increases blood supply to the gastric mucosa relatively to the reduced gastric secretion. Nicotine is either not associated with the development of peptic ulcers, or it exerts its ulcerogenic action via other mechanisms than change of acid secretion and gastric mucosal blood flow.