Cerebrospinal fluid amino acids in relation to neurological status in experimental portal-systemic encephalopathy

Using an indwelling cisterna magna catheter technique, serial CSF samples were analyzed for amino acid content in rats at various stages of portal-systemic encephalopathy resulting from ammonium acetate administration following portacaval anastomosis. Anastomosis alone resulted in increased CSF concentrations of glutamine, tyrosine, phenylalanine, glutamate and alanine. GABA levels, on the other hand were not significantly changed. Onset of severe neurological symptoms following ammonium acetate administration resulted in selectively increased CSF alanine. Other amino acids were not further increased at severe stages of encephalopathy. Increased CSF alanine probably results from increased glutamine transamination in the brains of portacaval shunted rats.