title: Menthol relaxes rat aortae, mesenteric and coronary arteries by inhibiting calcium influx.
abstract: Menthol, a naturally occurring compound in mint, is known to give cold sensation. However, previous findings about its pharmacological activity in blood vessels are full of paradox. The present study investigated the action of menthol on vascular reactivity in different arteries isolated from male Sprague-Dawley rats, e.g. aortae, main mesenteric arteries and coronary arteries. The arterial segments were suspended in organ bath or in wire myograph for measurement of isometric force. Menthol concentration-dependently relaxed all three arteries with similar relaxing sensitivity in arteries contracted by different contractors, KCl, U46619 (9,11-dideoxy-9α,11α-methanoepoxy Prostaglandin F2α) and phenylephrine. Menthol-induced relaxations were unaffected by nitric oxide synthase inhibitor L-NAME, soluble guanylyl cyclase inhibitor ODQ, or mechanical removal of endothelium. Menthol also concentration-dependently suppressed 60mM KCl-induced constriction and CaCl2-induced contraction in Ca(2+)-free K(+)-containing solution. Calcium fluorescent imaging using fluo-4 showed that 10 min-incubation with 1mM menthol inhibited 60mM KCl-induced Ca(2+) influx in rat aortic smooth muscle cell line A7r5 and vascular smooth muscle of coronary arteries. To conclude, menthol induces relaxation and inhibits contraction in rat aortae, mesenteric and coronary arteries primarily through inhibiting Ca(2+) influx via nifedipine-sensitive Ca(2+) channels in vascular smooth muscle.
authors: Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China.
authors: Wai San
authors: WS
authors: Cheang
authors: Muk Yan
authors: MY
authors: Lam
authors: Wing Tak
authors: WT
authors: Wong
authors: Xiao Yu
authors: XY
authors: Tian
authors: Chi Wai
authors: CW
authors: Lau
authors: Zhiming
authors: Z
authors: Zhu
authors: Xiaoqiang
authors: X
authors: Yao
authors: Yu
authors: Y
authors: Huang
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000502:physiology*; D002460:Cell Line; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D008610:Menthol / Q000494:pharmacology*; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents; D008610:Menthol; D002118:Calcium