Regional brain amino acid and neurotransmitter derangements during abdominal sepsis and septic encephalopathy in the rat. The effect of amino acid infusions
H. R. Freund, M. Muggia-Sullam, R. LaFrance, J. Holroyde and J. E. Fischer
Regional amino acids and brain neurotransmitters were studied in 33 normal
and 32 rats with sepsis (induced by cecal ligation and puncture) infused
with different amino acid formulations. The brain amino acid pattern during
sepsis showed increased concentrations of most essential and six of the
nonessential amino acids. The most consistent finding was the accumulation
of indoleamines in all six brain regions studied during sepsis; increased
brain tryptophan levels presumably resulted in enhanced metabolism of
serotonin (5HT), increased production of 5-hydroxyindoleacetic acid
(5HIAA), and a high 5HT/5HIAA ratio. Infusion of branched-chain amino
acid-enriched formulas restored brain amino acid and neurotransmitter
profiles, decreasing levels of tryptophan, tyrosine, 5HIAA, and 5HT/5HIAA
ratios while increasing norepinephrine levels in some regions. These
alterations in brain neurotransmitter metabolism may be at least partially
responsible for the development of septic encephalopathy.
