TYROSINE-HYDROXYLASE ACTIVITY IN DISCRETE BRAIN-REGIONS FROM PREHEPATIC PORTAL HYPERTENSIVE RATS

BACKGROUND/AIMS: Portal hypertension in patients and rat models are ch aracterized by splanchnic and systemic hemodynamic alterations. Both t he central and autonomic nervous systems are implicated in its pathoph ysiology. The aim of our research was to study the tyrosine hydroxylas e activity and the rate limiting step in the biosynthesis of catechola mines in partial ligated portal hypertensive and in control rat brains . METHODOLOGY: The following seven discrete brain regions were investi gated: Subfornical Organ, Organum Vasculosum Lamina Terminalis, Median Eminence, Periventricular Nucleus, Area Postrema, Locus Coeruleus and Nucleus Tractus Solitarius. RESULTS: The enzyme activity showed a sig nificant increment in six nuclei and a decrease in Area Postrema Nucle us when portal hypertensive rats were compared to controls. CONCLUSION S: These results suggest the participation of some discrete brain regi ons in the mechanism of hepatic portal hypertension under the present rat model.