HEMODYNAMIC-EFFECTS OF 8-DAY OCTREOTIDE AND PRAZOSIN ADMINISTRATION IN PORTAL HYPERTENSIVE RATS

Background Octreotide and prazosin are both effective portal hypotensi ve drugs in the control or prevention of variceal bleeding. The presen t study was undertaken ro investigate the haemodynamic effects of octr eotide and prazosin, alone or in combination, in portal hypertensive r ats. Methods Portal hypertension was induced by partial portal vein li gation. Portal hypertensive rats were allocated into one of the four g roups - vehicle group (saline, 0.5 mt 12 h(-1)), octreotide group (30 mu gkg(-1) 12 h(-1)), prazosin group (0.4 mgkg(-1) 12 h(-1)), and octr eotide (30 mu g kg(-1) 12 h(-1)) plus prazosin (0.4 mgkg(-1) 12 h(-1)) group - with eight rats in each group. Prazosin or saline was adminis tered by gavage, whereas octreotide was administered by subcutaneous i njection. The drug was given on the day of ligation and continued for 8 consecutive days. Systemic as well as splanchnic haemodynamic parame ters were measured thereafter. Results Portal vein-ligated rats exhibi ted typical hyperdynamic stare compared with sham-operated rats. The p ortal venous pressure, portal tributary blood flow and cardiac index w ere significantly reduced by treatment of octreotide, prazosin or octr eotide plus prazosin in portal hypertensive rats. Hyperdynamic paramet ers of systemic, renal and portal territory vascular resistances, and renal as well as hepatic arterial blood flow were ameliorated by treat ment of octreotide or octreotide plus prazosin in portal hypertensive rats. Overall, octreotide treatment exerted more beneficial haemodynam ic effects than prazosin treatment. The combination of octreotide and prazosin exerted better haemodynamic effects in cardiac index but wors e effects in systemic as well as portal territory vascular resistance than octreotide treatment alone.