The effect of portocaval anastomosis on the permeability to horseradish peroxidase of cerebral vessels of the rat.

The blood-brain barrier to horseradish peroxidase (HRP) was tested in rats with hepatic encephalopathy induced by portocaval anastomosis. An increased number of vesicles containing HRP was seen in endothelial cells. Basement membranes of some vessels and the adjacent neuropil were filled with HRP. Astrocytes showed swollen end-feet. The cytoplasm of astrocytes adjacent to HRP containing basement membranes was evenly filled with HRP. This phenomenon could be caused either by cellular hyperactivity or by leaking membranes due to cell damage.