title: The essential oil of Citrus bergamia Risso induces vasorelaxation of the mouse aorta by activating K(+) channels and inhibiting Ca(2+) influx.
abstract: OBJECTIVE
  The aim of this study was to explore the effect of the essential oil of Citrus bergamia Risso (bergamot) on mouse blood vessels and to analyse the mechanism of this effect from a pharmacological perspective.
  
  
  METHODS
  We investigated the effect of bergamot essential oil (BEO) on vascular tonus during contraction of mouse aorta induced by prostaglandin F2α (PGF2α ) or noradrenaline (norepinephrine).
  
  
  RESULTS
  In mouse aortic rings, BEO (0.01, 0.1 and 0.2% v/v) reduced contraction in a dose-dependent manner, and relaxed the vascular tonus induced by PGF2α . No significant difference in the extent of vasorelaxation induced by 0.1% (v/v) BEO was evident when rings with intact endothelium and endothelium-denuded rings were compared. When aortic rings were suspended in a medium that was Ca(2+) -free but contained 80 mm KCl, addition of CaCl2 (1, 2.5 or 5 mm) induced contraction in a dose-dependent manner. However, addition of Ca(2+) after incubation of the rings with BEO strongly suppressed CaCl2 -induced contraction. Further, the K(+) -channel blocker tetraethylammonium chloride partially blocked BEO-induced vasorelaxation.
  
  
  CONCLUSIONS
  Our findings suggest that BEO may induce endothelium-independent vasorelaxation by regulating the vascular tone of smooth muscle. Activation of K(+) channels and inhibition of Ca(2+) influx may be involved in vasorelaxation of mouse aorta elicited by BEO.
authors.affiliation: Department of Basic Nursing Science, School of Nursing, Korea University, Seoul, Korea.
authors.forename: Purum
authors.initials: P
authors.lastname: Kang
authors.forename: Suk Hyo
authors.initials: SH
authors.lastname: Suh
authors.forename: Sun Seek
authors.initials: SS
authors.lastname: Min
authors.forename: Geun Hee
authors.initials: GH
authors.lastname: Seol
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002957:Citrus / Q000737:chemistry*; D015237:Dinoprost; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine; D009822:Oils, Volatile / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D010938:Plant Oils / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D019789:Tetraethylammonium / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D014665:Vasodilator Agents; C068336:bergamot oil; D019789:Tetraethylammonium; D015237:Dinoprost; D002118:Calcium; D009638:Norepinephrine