Objective: To investigate the anti-hypertensive effects of extracts from leaves of Apocynum venetum L. (ELA) and its mechanisms. Method: Twelve Beagle dogs were used to establish hypertensive mode by two-kidney two-clip method; endothelial cells were cultured to determine effects of ELA on nitric oxide(NO) output and endothelial nitric oxide synthase(eNOS) activities; then Western blot method was involved in current study to detect effects of ELA on eNOS

phospho-endothelial NOS(p-eNOS)

phosph-phosphponositide-3 kinase(p-PI3K) and phosph-protein kinase B(p-Akt) expression. Result: Contractive and diastolic pressure of Beagle dogs showed degression in dose-dependent manner after ELA was administrated (P<0.01). Moreover

NO yield and eNOS activities of EA hy 926 cells were increased significantly when these cells incubated with ELA (P<0.01). It was also showed that ELA enhanced expression of eNOS

p-eNOS

p-PI3K and p-Akt in endothelial cells. Conclusion: ELA shows significant anti-hypertensive properties. The mechanisms may be associated with activation of PI3K/Akt pathway in endothelium.