IN-VITRO CONTRACTILITY PATTERNS OF PORTAL VEINS FROM HEALTHY AND LIVERCIRRHOTIC RATS - INFLUENCE OF CALCIUM-ANTAGONISTS AND OCTREOTIDE

According to Poiseuille's law portal pressure is inversely related to r4. Thus, minor changes in radius dramatically influence intravascular pressure. Since the radius is actively regulated by contraction, this study elucidates in vitro contractility patterns of portal veins from healthy and liver cirrhotic rats. The results demonstrate that contra ctility amplitudes of portal veins from cirrhotic rats are increased i n comparison to healthy animals. Calcium antagonists reduce amplitude and motility both in cirrhotic and healthy rats to the same degree. Th e same holds true for octreotide but significantly more in the cirrhot ic group. Obviously, the maintenance of portal hypertension is support ed by an active element of the portal vein, which can be controlled in vitro.