Beneficial effects of combined terlipressin and tetramethylpyrazine administration on portal hypertensive rats

The purpose of this study was to investigate the therapeutic effects of terlipressin (TP) alone or in combination with tetramethylpyrazine (TMP) on anesthetized portal hypertensive rats. Portal hypertension was induced by either partial portal vein ligation (PVL, without cirrhosis) or bile duct ligation (BDL, with cirrhosis) in Sprague-Dawley rats. Each PVL or BDL rat received only one of the two regimens: vehicle for 3 min followed by TP (0.017 mg.kg(-1)min(-1) for 3 min) or TMP (10 mg.kg(-1)min(-1) for 3 min) followed by TP. In PVL rats, infusion of vehicle followed by TP induced significant reduction of portal venous pressure (PVP, -15.0 +/- 1.0%) and prominent elevation of mean arterial pressure (MAP, 57.3 +/- 8.1%) as well as total peripheral resistance (TPR, 113 +/- 11%) from baseline, and there was a cardiodepressant response (cardiac index, CI, -26.3 +/- 1.1%). Infusion of TMP followed by TP induced significant reduction of PVP (-20.3 +/- 0.4%) and CI (-9.9 +/- 1.28) and significant elevation of MAP (31.3 +/- 2.5%) and TPR (46.0 +/- 4.1%) from baseline. In BDL rats, infusion of vehicle followed by TP also induced significant reduction of PVP (-13.8 +/- 1.7%) but an increase in MAP (57.1 +/- 2.2%) and TPR (101 +/- 6%) from baseline, and there also was a cardiodepressant response (CI, -21.4 +/- 2.3%). Infusion of TMP followed by TP induced significant reduction of PVP (-18.9 +/- 1.4%) and CI (-11.9 +/- 2.1%), but an increase in MAP (36.2 +/- 2.5%) and TPR (55.0 +/- 5.2%). Compared with vehicle followed by TP, TMP not only significantly enhanced portal hypotensive (PVP reduction) effects of TP but also attenuated the systemic presser (MAP and TPR elevation) and cardiodepressant (CI reduction) effects of TP in both PVL and BDL rats. Our results suggest that TP, alone or in combination with TMP, induced portal hypotensive effects in two models of portal hypertensive rats. Combination of TP and TMP was beneficial in enhancing portal hypotensive effects of TP and ameliorating the systemic presser and cardiodepressant effects of TP.