Prehepatic portal hypertension in rats modifies norepinephrine metabolism in hypothalamus, medulla oblongata and portal vein.

The present experiments investigated the possible relationship between portal hypertension and norepinephrine metabolism in the central nervous system (hypothalamus and medulla oblongata) and the portal vein in the rat. Group I (72), portal hypertensive, and group II (70) sham-operated animals, were sacrificed day 14, and endogenous norepinephrine content, uptake and release from hypothalamus, medulla oblongata, and portal vein were investigated. In group I our results showed increases in norepinephrine storage (69%; 8.3%) and release (19.7%; 43.8%) and a diminished uptake (42.3%; 27.5%) in the hypothalamus and medulla oblongata, respectively. Portal veins showed a decreased content and uptake (62.5% and 43.5%, respectively) and increased release (25%) compared to group II rats. These results suggest a close relationship between the central nervous system and rat portal hypertension, perhaps related to modifications of central sympathetic activity.