title: Effect of bedding changes and room ventilation rates on blood and brain ammonia levels in normal rats and rats with portacaval shunts.
abstract: Normal rats and rats with portacaval shunts were exposed to low concentrations of atmospheric ammonia generated from decomposing urine and feces. The ammonia concentration in the atmosphere was varied by altering the effective ventilation rate, animal density in the enclosure, and bedding change frequency. Atmospheric ammonia concentrations in the animal holding areas varied inversely with the frequency of bedding change and the rate of air exchange. Significant differences were found between normal and shunted animals in blood ammonia and alkaline phosphatase; brain ammonia, glutamate, and glutamine; and body weight. However, these alterations were the same regardless of the atmospheric ammonia concentration; there were no differences within the control group or shunted group housed in the different conditions. The findings suggest that in the range of ammonia concentrations in this study (0 to 9 ppm), ammonia taken in through the respiratory tract is not accumulated in the body to any significant extent.
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000494:pharmacology*; D000641:Ammonia / Q000032:analysis* / Q000097:blood / Q000494:pharmacology; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D006799:Housing, Animal; D008297:Male; D011167:Portacaval Shunt, Surgical / Q000662:veterinary*; D051381:Rats; D011919:Rats, Inbred Strains; D012107:Research Design; D012119:Respiration / Q000187:drug effects; D014691:Ventilation
chemical_list: D000393:Air Pollutants; D000641:Ammonia