A comparative study on the adenine nucleotide metabolism of acid-dependent and non-acid-dependent acute gastric mucosal injury in the rat

Abstract

Intragastric (ig) administration of 96% ethanol (EtOH, non-acid-dependent model) and 0.6 mol/L HCl (acid-dependent model) produces acute mucosal lesions in the rat stomach.

Aim

The aim of this study was to compare the EtOH- and HCl-induced biochemical changes and ulcerations of gastric mucosa in the rat examined at different times after administration of the necrotizing agents.

Materials and methods

The observations were carried out on Sprague-Dawley rats weighing 180–210 g. The animals were fasted for 24 h before the experiment but received water freely; 1 ml 96% EtOH or 0.6 mol/L HCl was given ig. The rats were sacrificed at 0, 1, 5, 15, 30 and 60 min after administration of necrotizing agents, when the stomach was removed and the number and severity of mucosal lesions was noted. The mucosa was scraped and its ATP, ADP, AMP and lactate levels were measured enzymatically; the cAMP level was measured by RIA. The ratio of ATP/ADP, adenylate pool (ATP+ADP+AMP) and ‘energy charge’ [(ATP+0.5ADP)/(ATP+ADP+AMP)] were calculated.

Results

• 1. The number and severity of mucosal lesions reached about 50% of total by 5 min after application of the necrotizing agents;

• 2. The ATP level decreased between 5 and 30 min, but thereafter its level increased (ADP changed in the opposite direction) in both models;

• 3. The cAMP level increased at 1 and 5 min but decreased later;

• 4. ‘Energy charge’ and lactate level did not change.

Conclusions

The biochemical changes in acid-(HCl) and non-acid-(EtOH) dependent gastric ulcer models are similar, but these changes appear earlier in the acid-dependent model.