Tolerance of neonatal rat brain to acute hyperammonemia.
The aim of the present work was to study the effects of hyperammonemia on brain energy metabolism in neonatal rats. Rats were rendered hyperammonemic by ammonium acetate administration. This decreased brain ATP concentrations but enhanced brain ammonia and lactate levels in both adult and neonatal rats. In adult rats, the decrease in brain ATP concentrations was accompanied by a plunge in the respiratory control rate (RCR) of brain mitochondria. However, the ammonia-induced effect on RCR was not observed in neonatal rats, suggesting that the fall in ATP levels observed in neonatal rats would not be due to an impairment of mitochondrial respiratory efficiency. However, in neonatal rats the increase in blood and brain ammonia concentrations did not change brain glutamate concentrations but decreased glutamine contents. These results may be of relevance for the understanding of the resistance of neonatal rats observed in this work to acute ammonia toxicity
García
M Victoria
MV
Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Salamanca, Edificio Departamental, Plaza de los Doctores de la Reina s/n., E-37007 Salamanca, Spain.
López-Mediavilla
Casilda
C
Juanes de la Peña
María C
MC
Medina
José M
JM
D000208:Acute Disease; D000255:Adenosine Triphosphate / Q000378:metabolism; D000367:Age Factors; D000641:Ammonia / Q000378:metabolism / Q000633:toxicity; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D022124:Hyperammonemia / Q000139:chemically induced / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D019344:Lactic Acid; D018698:Glutamic Acid; D000641:Ammonia; D000255:Adenosine Triphosphate