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

Abstract

SUMMARY The effects of an intravenous infusion of nicotine at a dose of 2.5, 5.0, 7*5, or 100 ,g kg-'h-' 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 smokinf of five cigarettes per two hours induced similar changes to the intravenous infusion of 5 ,ug kg7 h71 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.Gastric and duodenal ulcers occur more frequently in smokers than in non-smokers.' 2 Peptic ulcers heal less well in smokers than in non-smokers.3?6 Since the work of Virchow, decreased mucosal blood flow has been thought to be one of the factors responsible for the loss of mucosal integrity in the upper gastrointestinal tract.7 8 In the following study the effects of intravenous nicotine infusion on gastric mucosal blood flow and acid secretion were investigated.Methods

Effects of Standard Cigarette Smoke and Nicotine-Reduced Cigarette Smoke on Plasma Concentrations of Indomethacin Administered Orally to Rats.

“…In the previous study, we have already observed that subcutaneous nitotine caused a decrease in the plasma IM and O-DM-IM con centrations after oral IM, which was similar to the effects of cigarette smoke exposure, and that nicotine did not cause such an effect after intravenous IM (10). Accordingly, the decreasing effects caused by nicotine and cigarette smoke exposure may have involved re tardation of IM absorption from the gastrointestinal tract, i.e., being mediated by a reduction of gastric mucosal blood flow (12) and/or an inhibition of gas trointestinal motility (11). On the other hand, as consti tuents other than nicotine in the gaseous phase of cigarette smoke, carbon monoxide, carbon dioxide, nit rogen oxides, ammonia, volatile sulfur and nitrogen containing compounds and so on were also determined (13).…”

Dysregulation of gastric H,K-ATPase by cigarette smoke extract

“…Clinical studies showed that smoking may stimulate [25][26][27][28] , inhibit [29,30] or have no effect [31,32] on gastric acid secretion. Such disparity between studies may be explained, in part, by the differences in nicotine content and number of cigarettes used, and by the lack of adequate controls due to marked individual variability of basal gastric secretion.…”

Smoking Tobacco and Gastrointestinal Pathophysiology and Diseases

“…The effects of an intravenous infusion of nicotine at a dose 2.5 -10 μ g/kg per h on pentagastrin -stimulated gastric mucosal blood fl ow and acid secretion were studied in healthy male non -smokers. Nicotine reduced volume secretion, acid secretion, and Neutral Red clearance in a dose -dependent manner [21] . A similar change was seen in healthy male smokers smoking fi ve cigarettes per 2 h. PGF 2 α , a cyclooxygenase product with vascular effect on a submucosal microcirculation, and thromboxane ( Tx )B 2 , a potent platelet aggregator and vasoconstrictor, play an important role in the mucosal blood circulation.…”