Dopaminergic Dysfunction in Experimental Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome that appears as a consequence of acute or chronic liver dysfunction. Ammonia is considered central to its pathogenesis, but the factors contributing to the neurological dysfunction the disorder entails remain unclear (Butterworth et al., 2002). In humans with HE, it has been suggested that the basal ganglia may be selectively affected (Spahr et al., 2002), and lesions detected by magnetic resonance in the basal ganglia of such patients (Spahr et al., 2000; Burkhard et al., 2003) have been associated with movement disorders (Layrargues, 2001; Spahr et al., 2002; Weissenborn & Kolbe, 1998). The mechanisms by which liver failure leads to abnormal motor function are not clear, but the symptoms described in HE patients (Spahr et al., 2002) are similar to those of Parkinson’s disease (PD).