SELECTIVE LOSS OF PALLIDAL DOPAMINE-D(2) RECEPTOR DENSITY IN HEPATIC-ENCEPHALOPATHY

The binding parameters of [H-3]SCH 23390 and [H-3]spiperone (radioliga nds for dopamine D1 and D2 receptors, respectively) were investigated in autopsied frontal cortex, caudate nucleus and globus pallidus/putam en of cirrhotic patients who died in hepatic coma as well as in age- a nd sex-matched controls. Specific [H-3]SCH 23390 binding site densitie s were unchanged in all regions; in contrast, specific [H-3]spiperone binding site density was decreased (by 44%, P<0.001) in the globus pal lidus/putamen of patients with HE. Decreased densities of pallidal D2 binding sites could relate to the motor dysfunctions commonly encounte red in human HE.