title: Endothelium- and smooth muscle-dependent vasodilator effects of Citrus aurantium L. var. amara: Focus on Ca(2+) modulation.
abstract: Neroli, the essential oil of Citrus aurantium L. var. amara, is a well-characterized alleviative agent used to treat cardiovascular symptoms. However, because it has been found to have multiple effects, its mechanism of action requires further exploration. We sought to clarify the mechanism underlying the actions of neroli in mouse aorta. In aortic rings from mice precontracted with prostaglandin F2 alpha, neroli induced vasodilation. However, relaxation effect of neroli was decreased in endothelium-denuded ring or pre-incubation with the nitric oxide synthase inhibitor NG-Nitro-l-arginine-methyl ester (L-NAME). And also, neroli-induced relaxation was also partially reversed by 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ), a soluble guanylyl cyclase (sGC) inhibitor. In addition, neroli inhibited extracellular Ca(2+)-dependent, depolarization-induced contraction, an effect that was concentration dependent. Pretreatment with the non-selective cation channel blocker, Ni(2+), attenuated neroli-induced relaxation, whereas the K(+) channel blocker, tetraethylammonium chloride, had no effect. In the presence of verapamil, added to prevent Ca(2+) influx via smooth muscle voltage-gated Ca(2+) channels, neroli-induced relaxation was reduced by the ryanodine receptor (RyR) inhibitor ruthenium red. Our findings further indicate that the endothelial component of neroli-induced vasodilation is partly mediated by the NO-sGC pathway, whereas the smooth muscle component involves modulation of intracellular Ca(2+) concentration through inhibition of cation channel-mediated extracellular Ca(2+) influx and store-operated Ca(2+) release mediated by the RyR signaling pathway.
authors.affiliation: Department of Basic Nursing Science, School of Nursing, Korea University, Seoul 02841, Republic of Korea.
authors.forename: Purum
authors.initials: P
authors.lastname: Kang
authors.affiliation: Department of Basic Nursing Science, School of Nursing, Korea University, Seoul 02841, Republic of Korea.
authors.forename: Kang-Hyun
authors.initials: KH
authors.lastname: Ryu
authors.affiliation: KT&G Research Institute, Daejeon 305-805, Republic of Korea.
authors.forename: Jeong-Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: KT&G Research Institute, Daejeon 305-805, Republic of Korea.
authors.forename: Hyo-Keun
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Basic Nursing Science, School of Nursing, Korea University, Seoul 02841, Republic of Korea. Electronic address: ghseol@korea.ac.kr.
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 / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D008810:Mice, Inbred C57BL; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009822:Oils, Volatile / Q000494:pharmacology*; D010069:Oxadiazoles / Q000494:pharmacology; D010656:Phenylephrine; D011810:Quinoxalines / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D004791:Enzyme Inhibitors; D053496:Inositol 1,4,5-Trisphosphate Receptors; D009822:Oils, Volatile; D010069:Oxadiazoles; D011810:Quinoxalines; D019837:Ryanodine Receptor Calcium Release Channel; D014665:Vasodilator Agents; D010656:Phenylephrine; D015237:Dinoprost; D006162:Guanylate Cyclase; D002118:Calcium
keywords: Citrus aurantium L. var. amara; Endothelium; Vascular smooth muscle; Vasodilation