Linalyl acetate as a major ingredient of lavender essential oil relaxes the rabbit vascular smooth muscle through dephosphorylation of myosin light chain.
In a preliminary experiment, we found that lavender essential oil relaxes vascular smooth muscle. Thus, the present experiments were designed to investigate the relaxation mechanism of linalyl acetate as the major ingredient of lavender essential oil in rabbit carotid artery specimens. Linalyl acetate produced sustained and progressive relaxation during the contraction caused by phenylephrine. The relaxation effect of linalyl acetate at a concentration near the EC50 was partially but significantly attenuated by nitroarginine as an inhibitor of nitric oxide synthase, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one as an inhibitor of guanylyl cyclase, or by the denudation of endothelial cells. In specimens without endothelium, the phenylephrine-induced contraction and phosphorylation of myosin light chain (MLC) were significantly attenuated after the pretreatment with linalyl acetate. The relaxation caused by linalyl acetate in the endothelium-denuded specimens was clearly inhibited by calyculin A as an inhibitor of MLC phosphatase, although not by ML-9 as an inhibitor of MLC kinase. Furthermore, suppression of the phenylephrine-induced contraction and MLC phosphorylation with linalyl acetate was canceled by the pretreatment with calyculin A. These results suggest that linalyl acetate relaxes the vascular smooth muscle through partially activation of nitric oxide/cyclic guanosine monophosphate pathway, and partially MLC dephosphorylation via activating MLC phosphatase.
Koto
Ruriko
R
Department of Biosystem Regulation, Institute of Biomaterials & Bioengineering, Graduate School, Tokyo Medical & Dental University, Tokyo, Japan.
Imamura
Masatoshi
M
Watanabe
Chie
C
Obayashi
Satoshi
S
Shiraishi
Mitsuya
M
Sasaki
Yasuharu
Y
Azuma
Hiroshi
H
D000818:Animals; D001381:Azepines / Q000494:pharmacology; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D027523:Lavandula; D008297:Male; D008387:Marine Toxins; D008954:Models, Biological; D039821:Monoterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D018994:Myosin Light Chains / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009822:Oils, Volatile / Q000737:chemistry*; D010080:Oxazoles / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010938:Plant Oils / Q000737:chemistry*; D011817:Rabbits; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*
D001381:Azepines; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D039821:Monoterpenes; D018994:Myosin Light Chains; D009822:Oils, Volatile; D010080:Oxazoles; D010938:Plant Oils; D014662:Vasoconstrictor Agents; C056218:ML 9; D010656:Phenylephrine; C074463:linalyl acetate; C059041:calyculin A; D009219:Myosin-Light-Chain Kinase; D043263:Myosin-Light-Chain Phosphatase; C045718:lavender oil