Abstract: AIM: To explore the effects of total of flavonoid Hippophae rhamnoides L (TFH) on intracellular free calcium ([Ca²⁺]_i) in vascular smooth muscle cells (VSMC).METHODS: The cultured rabbit aortic smooth muscle cells were expose to high K⁺, norepinephrine (NE) and angiotensin II(Ang Ⅱ), which were compared with those of verapamil(Ver), and then the changes of [Ca²⁺]_i in VSMC were determined by using the new generation of fluorescent Ca²⁺-indicater fluo-3/AM.RESULTS: TFH (100 mg·L ^-1) had no significant effect on theresting[Ca²⁺]_i.However, and TFH(60 ^-100 mg·L ^-1) inhibited the elevation of [Ca²⁺]_i induced by high potassium-depolarization in a concentration-dependent manner. These effects were similar to but weaker than those of Ver.In addition, TFH (80, 100 mg·L ^-1) inhibited the elevation of [Ca²⁺]_i induced by NE or Ang II in the presence of extracellular Ca²⁺.In the absence of extracellular Ca²⁺, TFH (80, 100 mg·L ^-1) also had some blocking effects on the NE-induced [Ca²⁺]_i increase.CONCLUSION: TFH may decrease the [Ca²⁺]_i of VSMCs by blocking both voltage-dependent calcium channels and receptor-operated calcium channels, which may be one of TFH vasodilative and hypotensive mechanisms.

Key words: total flavonoids of Hippophae rhamnodies L, vascular smooth muscle cell, intracellular free calcium, calcium antagonist, rabbit