Betel quid chewing damaged gastric mucosa: protective effects of cimetidine and sodium bicarbonate.

The effects of cimetidine and NaHCO3 on gastric acid back-diffusion (either the H+ loss or the Na+, K+ and CA++ gain in the gastric lumen) and mucosal ulceration were studied in rats with chronic feeding of betel quid chewing (BQC)- or its individual component-containing food. After 30 and 90 days of feeding, the animal was fasted for 24 hrs and vagotomized. An acid solution (100 mM HCl plus 54 mM NaCl) with or without drugs was irrigated in the rat stomach for 3 hrs. The results indicated that BQC and its individual component produced a variety of change in enhancement in acid solution-induced acid back-diffusion and mucosal hemorrhagic ulceration but in decrease of gastric mucus secretion. These parameters were dose-dependently reversed by intragastric cimetidine (50-300 mg/kg) in BQC-treated rats. Similar but lesser effect than cimetidine (300 mg/kg) was obtained by intragastric administration of NaHCO3 (52 mg/kg). It is concluded that in BQC- or its component-feeding rats, the enhancement in acid back-diffusion and the reduction in mucus secretion are at least in part responsible for the formation of hemorrhagic ulceration which can be inhibited by intragastric cimetidine or NaHCO3.