Central vs. peripheral spontaneous behavioral abnormalities in experimental hepatic encephalopathy.

The most common behavioral disturbance reported in experimental chronic hepatic encephalopathy (HE) refers to changes in spontaneous activities in an open field in the portacaval-shunted (PCS) rat. A major problem at present is that not all of these findings of abnormal PCS behavior are in agreement. We, therefore, investigated the total, central, and peripheral locomotor and rearing activities in an open field 2 and 6 months after PCS surgery. The results revealed that, 2 months after surgery, locomotor and rearing activities were lower in PCS rats compared to controls. At 6 months, a partial remission of the behaviors had occurred. Clearly though, as pointed out by the peripheral behavioral recordings, the hypoactivity persisted and, interestingly, central locomotor activity as higher in PCS rats than in controls. This novel finding may be attributed to the special study of central vs. peripheral components of the spontaneous open-field behavior in experimental chronic HE. Our observations may also help explain some of the seemingly discrepant results available in the literature.