Effect of ligustrazine on Ca2+ uptake by inside-out red cell membrane vesicles from renal hypertensive rats.

The effect of ligustrazine (Lig) on blood pressure and Ca2+ uptake by inside-out red cell membrane vesicles (IOV) was investigated in renal hypertensive rats (RHR). After oral administration of Lig (30 mg/kg body weight/day) for 10 days, the blood pressure of RHR was not significantly changed (before vs after experiment: 147.50 +/- 2.50 vs 150.00 +/- 13.42 mmHg). The active Ca2+ uptake rate of IOVs from RHR was 5.03 +/- 1.15 nmol/ng IOV protein/min, and this was lower than that of IOVs from normotensive Wistar rats (8.95 +/- 1.08 nmol/ng IOV protein/min, P less than 0.01). In RHR, no change in IOV Ca2+ uptake capacity was observed after administration of Lig in vivo. Experiments in vitro showed that Lig markedly reduced Ca2+ uptake by IOVs from both RHR and control rats. The results indicate that the active Ca2+ transport capacity of red cell membranes is decreased in RHR and not significantly affected by oral administration of Lig; this drug, however, exerts an inhibitory effect on the transport process in vitro.