Intensification of ammonium diffusion from rat gastrointestinal tract during acute barbiturate intoxication.

In rats with acute sodium thiopental intoxication, ammonium concentration in the caecal contents was at the lower boundary of control values, while accumulation of ammonium in lavage solution injected intraperitoneally was 50-70% accelerated. Blood ammonium level did not change 3 h after sodium thiopental injection in a dose inducing sopor, but increased 3-fold during coma modeling. Intragastric administration of gentamicin (antibiotic poorly absorbed from the gastrointestinal tract) 2-fold reduced ammonium concentration in the caecal contents and prevented hyperammoniemia during induction of barbiturate coma. Hence, increased permeability of the gastrointestinal wall for ammonium promotes the development of hyperammoniemia in rats during induction of barbiturate coma.