[Therapy of hepatic encephalopathy. Changes in the cerebrospinal fluid concentration of catecholamine neurotransmitters, ammonia and amino acids in the course of an infusion treatment with branched-chain amino acids].

Infusions containing branched-chain amino acids have recently been used for the therapy of hepatic coma. Their mode of action was attributed to a reduction in the intracerebral concentrations of the aromatic amino acids with resultant normalization of the neurotransmitters noradrenaline, dopamine and serotonin, synthesized from these amino acids. In order to further clarify this therapeutic mechanism an infusion solution consisting of branched-chain amino acids and ammonia-reducing amino acids was administered to patients with porto-systemic encephalopathy. The amino acid pattern, the ammonia in plasma and liquor, and the neurotransmitters noradrenaline, adrenaline and dopamine, in the liquor were determined before and after the course of treatment. Our studies show that the therapeutic effect of branched-chain amino acids in the therapy of hepatic encephalopathy is based on an effective intracerebral reduction of the ammonia concentration by 61%. The actual concentrations of the neurotransmitters were not significantly modified by the therapy. This opens to question the hypothesis that the neurotransmitters are responsible for the development of hepatic encephalopathy.