title: Nitric oxide-dependent hypotensive effects of wax gourd juice.
abstract: BACKGROUND
  The wax gourd (Benincasa hispida (Thunb) Cong.) is a long-season vegetable that has been used in traditional Chinese medicine to treat high blood pressure. However, precise details of its effect and the mechanism of action involved are still lacking.
  
  
  METHODS
  Ten-fold-condensed wax gourd juice was used for the experiments. We measured (1) blood pressure of anesthetized normal Wistar rats in vivo, (2) isolated rat aortic contraction and relaxation, and (3) nitric oxide production from cultured porcine endothelial cells. The rats mentioned had not been treated with the investigational medicine.
  
  
  RESULTS
  Intravenous injection of the juice produced a dose-dependent decrease in blood pressure. Treatment with the juice induced concentration-dependent relaxation of isolated rat aortic rings that had been precontracted with noradrenaline. The relaxation induced by the juice was strongly inhibited by treatment with the nitric oxide (NO) synthase inhibitor N(G)-nitro-l-arginine methyl ester hydrochloride (l-NAME) or endothelial denudation. Treatment with the juice produced NO from cultured porcine aortic endothelial cells. This NO production was significantly inhibited by l-NAME.
  
  
  CONCLUSIONS
  The present findings suggest that wax gourd juice exerts a hypotensive effect via endothelium-dependent vasodilation. The main endothelium-derived relaxing factor involved might be NO.
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Nakashima
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Shigekuni
authors.forename: Takeshi
authors.initials: T
authors.lastname: Obi
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Shiraishi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Hideo
authors.initials: H
authors.lastname: Yamasaki
authors.forename: Takeomi
authors.initials: T
authors.lastname: Etoh
authors.forename: Sumio
authors.initials: S
authors.lastname: Iwai
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002478:Cells, Cultured; D019662:Cucurbitaceae / Q000737:chemistry*; D066298:In Vitro Techniques; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013552:Swine
chemical_list: D000959:Antihypertensive Agents; D009569:Nitric Oxide