Abstract: Aim The Effect of panax notoginseng(PNS)andits monomers Rb₁ and Rg₁ on cerebral blood f low (CBF)in rats with middle cerebral artery occlusion(MCAO)was observed.Methods Sixty Wistarrats wererandomizedinto 7 groups, which weresubdividedinto 5 MCAO experimental groups and one MCAO control group operated via internal artery and one sham-operated(SO) control group undergone the samesurgical procedurebut without MCAO.3 MCAO experimental mental groups weregiven different drugs respectively in the doses of Rg₁ 20 μg·kg^-1 (iv);Rb₁ 20 μg·kg^-1 (iv)and nimodipine.Nim 5 μg·kg^-1 (iv)30 minutes beforeandimmediately after MCAO.Ano ther 2 MCAO groups weregiven PNS(200 mg·kg^-1 or 400 mg·kg^-1, po.)for 10 days and MCAO was observed 30 minutes after the final administration.Results CBF in Rb₁ group, Nim group and PNS group was increased signi ficantly (P<0.01), as compared with thatin the MCAO control group, whereas in Rg₁ group it was decreased obviously(P<0.05).Electron microscopic structural analysis indicated that Rb₁, Rg₁, PNS and Nim obviously alleviated brain injury and neuron necrosis caused by ischemia.The samedosage of PNScould markedly increase the action of superoxide dismutase (SOD)and decrease the concentration of nitrie oxide(NO).Conclusion Different from Rg₁, Rb₁ and PNScan increase CBF in MCAO region.Allthese drugs can lessen brain injury and neuron necrosis.The mechanismmay berelated to thereduction of Ca²⁺and NO contentin ischemic reg ion.

Key words: panax notoginseng(PNS), middle cerebral artery occlusion (MCAO), cerebral blood flow (CBF)