Octreotide is an effective portal hypotensive drug in the control of variceal bleeding. Tetrandrine is a type of calcium channel blocker recently reported to reduce portal hypertension. The present study was undertaken to investigate the haemodynamic effects of octreotide and tetrandrine, alone and in combination, in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation. Portal hypertensive rats were allocated into one of the four groups: vehicle group (saline, 0.5 mL/day), octreotide group (100 μg/kg per 12 h), tetrandrine group (20 mg/kg per 12 h), and octreotide (100 μg/kg per 12 h) plus tetrandrine (20 mg/kg per 12 h) group. Tetrandrine or saline was administered by gavage, and octreotide by subcutaneous injection. The drug was given for 8 consecutive days, starting 1 day before ligation and continuing onwards. Haemodynamic parameters were measured thereafter, using the radioactive microsphere method. The portal venous pressure and portal tributary blood flow were significantly reduced, while portal territory and renal vascular resistances were significantly enhanced, by octreotide, tetrandrine, or octreotide plus tetrandrine in portal hypertensive rats, compared with the vehicle group. Our results showed that long‐term administration of octreotide, tetrandrine, or octreotide plus tetrandrine led to portal hypotensive effects in portal hypertensive rats, but octreotide alone exerted better anti‐hyperdynamic effects compared with tetrandrine alone. A combination of octreotide and tetrandrine offered no major beneficial anti‐hyperdynamic effects compared with octreotide alone.

Tetrandrine is a calcium channel antagonist with reported anti-hypertensive effect. However, the potential role of tetrandrine as a therapeutic agent in portal hypertension has yet to be explored. The present study aimed To investigate the chronic effects of two calcium channel antagonists, tetrandrine and verapamil, on the portal pressure of portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Sprague-Dawley rats. Animals were allocated into one of the two groups: tetrandrine group and verapamil group. Tetrandrine group was sub-divided into 10, 30, 50 mg/kg and vehicle (0.1 N HCl) subgroups. Verapamil group was sub-divided into 10, 30, 50 mg/kg and vehicle (saline) subgroups. Drug or vehicle was administered by gavage every 12 hours for 9 consecutive days, starting 2 days before ligation and continuing thereafter. After 9 days of tetrandrine treatment, portal venous pressure was significantly reduced in the subgroups receiving 30 and 50 mg/kg (12.6 +/- 0.3 mmHg, p < 0.05 and 9.7 +/- 0.6 mmHg, p < 0.01 vs. vehicle, respectively) as compared to vehicle group (14.1 +/- 0.6 mmHg). Mean arterial pressure was reduced only in the subgroup receiving the highest dose. There was no difference in body weight or heart rate between the vehicle and any tetrandrine subgroup. After 9 days of verapamil treatment, portal venous pressure was significantly reduced in the subgroups receiving 30 and 50 mg/kg (12.1 +/- 0.5 mmHg, p < 0.05 and 11.9 +/- 0.6 mmHg, p < 0.01 vs. vehicle, respectively) as compared to vehicle group (14.2 +/- 0.4 mmHg). Mean arterial pressure and heart rate were reduced only in the subgroup receiving the highest dose. There was no difference in body weight between the vehicle and any verapamil subgroup. Our results showed that chronic treatment of tetrandrine or verapamil reduced portal Venous pressure in portal hypertensive rats.