Aim To study molecular mechanisms of the effects of paeoniflorin on increasing expression of erythropoietin.Method RT-PCR and Western blot were used the investigate the influences of paeoniflorin,PI-3 kinase inhibitor (LY294002 30 ?mol?L-1),antagonist of adenosine A1 receptors(DPCPX 10 ?mol?L-1),agonist of A1 receptors(CPA 1 ?mol?L-1) and antagonist of adenosine A2a receptors(SCH58261 0.2 ?mol?L-1) on expression of erythropoietin in hypoxia and normoxia.Results Paeoniflorin decreases the expressions of erythropoietin in normoxia.However, paeoniflorin(2 ?mol?L-1) significantly increases the expression of erythropoietin mRNA after exposure to hypoxia environment from 8 to 24 hours in HepG2 cells.And this phenomenon is inhibited by LY294002,DPCPX and SCH58261.Conclusion Paeoniflorin increases erythropoietin mRNA levels by activating PI-3 kinase pathway through adenosine A1 and A2a receptors.

Many kinds of pathological irritations often make local-tissue face environmental hypoxia.These changes were messaged by increased accumulation of extracellular adenosine through their receptors.There are different roles for the four subtypes of adenosine receptors designated A1、A2a、A2b andA3.This review covers the effects of adenosine A1 receptors in different systems,such as protective effects on cells,improving immune response,regulation of blood pressure and glucose homeostasis.