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 nerv ous system (hypothalamus and medulla oblongata) and the portal vein in the rat. Group I (72), portal hypertensive, and group II (70) sham-op erated 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 obl ongata, respectively. Portal veins showed a decreased content and upta ke (62.5% and 43.5%, respectively) and increased release (25%) compare d to group II rats. These results suggest a close relationship between the central nervous system and rat portal hypertension, perhaps relat ed to modifications of central sympathetic activity.