Influence of chronic nicotine intake and acute ethanol challenge on gastric mucus level and blood flow in rabbits.

The effects of nicotine pretreatment on ethanol-induced gastric mucosal lesions and changes of gastric mucosal mucus levels and blood flow (GBF) were studied in anaesthetized rabbits. Nicotine treatment 25 or 50 micrograms/ml drinking water did not affect the volume of water consumption during the 10-day experimental period. It did not produce gastric mucosal lesions or affect the superficial adherent mucus content. The length of mucus-containing cells and the basal GBF were also unaffected. Intragastric administration of absolute ethanol reduced GBF, this effect was not altered by nicotine. However, the alkaloid potentiated the ulcerogenic actions of ethanol both on lesion formation and mucus depletion evoked by graded oral doses of ethanol (50 or 100%, v/v). Ultrastructurally, the mucous cells were more degenerated in the animals co-treated with nicotine and ethanol. It is concluded that reductions of mucus-containing cells and adherent mucus on the gastric mucosa are likely to be the contributory factors involved in the aggravating action of nicotine on ethanol-induced gastric mucosal lesions in rabbits.