Neurotransmitters in hepatic encephalopathy.

The pathogenesis of hepatic encephalopathy (HE), a neuropsychiatric disorder resulting from liver failure, is still a matter of debate. Recently attention has been focused on brain neurotransmitters. The accumulating evidence indicates that the imbalanced metabolism and turnover as well as the altered functions of neurotransmitters (dopamine, noradrenaline, serotonin, GABA) and false neurotransmitters (phenylethanolamine, octopamine, synephrine) may be of high importance in the pathomechanism of HE. Our data permit adding histamine (HA) to the multifactorial pathogenesis of HE. The enhanced rate of histidine influx into the brain following portocaval anastomosis and a dramatic increase in the HA content in the hypothalamus may suggest the involvement of HA in the symptomatology of hepatic encephalopathy.