INCREASED ACTIVITIES OF MAO(A) AND MAO(B) IN AUTOPSIED BRAIN-TISSUE FROM CIRRHOTIC-PATIENTS WITH HEPATIC-ENCEPHALOPATHY

Using radioenzymatic assays, activities of MAO(A) and MAO(B) were meas ured in autopsied brain tissue from cirrhotic patients who died in hep atic coma and in material from an equal number of age-matched subjects who were free from hepatic, neurological or psychiatric disorders. Ac tivities of both MAO(A) and MAO(B) were significantly increased in fro ntal cortex and caudate nucleus, two brain regions shown previously to be the site of functional and morphological alterations of astrocytes and increased concentrations of the acid metabolites of dopamine and serotonin. These findings suggest that increased monoamine metabolism and subsequent modifications of monoaminergic synaptic function could contribute to the pathogenesis of hepatic encephalopathy.