title: Vasorelaxant effects and mechanisms of action of Heracleum sphondylium L. (Apiaceae) in rat thoracic aorta.
abstract: BACKGROUND
  Aerial parts of Heracleum sphondylium L. (HS) are used in traditional medicine to treat hypertension. To provide pharmacological basis for this use, we investigated the vasorelaxant effects of a dichloromethane extract of HS (HSDE) and the mechanisms involved.
  
  
  METHODS
  Activity of HSDE was evaluated on rat isolated thoracic aortic rings.
  
  
  RESULTS
  HSDE induced vasorelaxation in phenylephrine (PE, 10(-6)mol/L) and high KCl-(6×10(-2)mol/L) pre-contracted aortic rings that was independent on the presence of endothelium. HSDE markedly decreased extracellular Ca(2+)-induced contraction in high-KCl and PE pre-challenged rings. It also inhibited the intracellular Ca(2+) release sensitive to PE (10(-6)M). The relaxant effect of HSDE were blunted by 4-amino-pyridine (4-AP, 10(-3)mol/L), an inhibitor of voltage-dependent K(+) channels.
  
  
  CONCLUSIONS
  Our results provide the first evidence that a dichloromethane extract of Heracleum sphondylium L. exhibits vasorelaxant properties through endothelium-independent mechanisms involving the inhibition of Ca(2+) mobilization and changes in Kv channel conductances. These data argue for its use as antihypertensive therapy in traditional medicine.
authors.affiliation: EA 4267 Fonctions et Dysfonctions Epithéliales, UFR des Sciences Médicales et Pharmaceutiques, 25030 Besançon, France.
authors.forename: François
authors.initials: F
authors.lastname: Senejoux
authors.forename: Céline
authors.initials: C
authors.lastname: Demougeot
authors.forename: Magdalena
authors.initials: M
authors.lastname: Cuciureanu
authors.forename: Anca
authors.initials: A
authors.lastname: Miron
authors.forename: Rodica
authors.initials: R
authors.lastname: Cuciureanu
authors.forename: Alain
authors.initials: A
authors.lastname: Berthelot
authors.forename: Corine
authors.initials: C
authors.lastname: Girard-Thernier
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000502:physiology; D030002:Heracleum; D066298:In Vitro Techniques; D008297:Male; D008752:Methylene Chloride / Q000737:chemistry; D010656:Phenylephrine / Q000494:pharmacology; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012997:Solvents / Q000737:chemistry; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts; D026902:Potassium Channel Blockers; D012997:Solvents; D014665:Vasodilator Agents; D010656:Phenylephrine; D008752:Methylene Chloride; D011189:Potassium Chloride