Early establishment of cerebral dysfunction after portacaval shunting.

Portacaval shunting in rats results in brain dysfunction, as indicated by reduced energy metabolism and behavioral abnormalities, as well as many biochemical changes in plasma and brain. No etiological connections have been made between these findings, which have been studied mainly 2 wk or more after shunting. To determine how soon the various abnormalities occur and which are associated temporally with the decrease in brain glucose use, we studied shunted and sham-operated rats between 6 h and 11 days after surgery. Six hours after portacaval shunting, plasma aromatic amino acids, brain glutamine, aromatic amino acids, 5-hydroxyindoleacetic acid, and tryptophan transport into the brain were all significantly higher than normal. Brain glucose use showed a downward trend and was fully depressed within 1 day. Plasma branched-chain amino acids and threonine were decreased, and brain serotonin and norepinephrine content increased only after 2 days; these changes were therefore dissociated from the other abnormalities that developed in a shorter period. The results showed that the cerebral dysfunction characteristic of portacaval shunting began within hours and was fully established by 2 days.