title: Bi-directional regulation of emodin and quercetin on smooth muscle myosin of gizzard.
abstract: This study is to reveal the characteristics of bidirectional regulation of emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) and quercetin on gizzard smooth muscle myosin. Our results indicate that: (a) emodin demonstrates stimulatory effects, and quercetin produces inhibitory effects on myosin phosphorylation and Mg(2+)-ATPase activities of Ca(2+)/calmodulin-dependent phosphorylated myosin in a dose-dependent manner; (b) a combination of emodin and quercetin enhances phosphorylation and Mg(2+)-ATPase activities for partially phosphorylated myosin and inhibits those activities for fully phosphorylated myosin; (c) 1-(5-Chloronaphthalene-1-sulfonyl)-1H2-hexahydro-1,4-diazepine inhibits myosin phosphorylation in the presence of emodin and/or quercetin. A combination of emodin and quercetin indicates its potential for modulating gastric-intestinal smooth muscle.
authors.affiliation: Department of Pharmacology, Dalian Medical University, Dalian, Liaoning 116027, PR China. houlizh@yahoo.com.cn
authors.forename: Hou-Li
authors.initials: HL
authors.lastname: Zhang
authors.forename: Ze-Yao
authors.initials: ZY
authors.lastname: Tang
authors.forename: Jing-Xian
authors.initials: JX
authors.lastname: Yang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
mesh_terms: D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D004642:Emodin / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005895:Gizzard, Avian / Q000033:anatomy & histology / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D010766:Phosphorylation; D011794:Quercetin / Q000494:pharmacology*; D024745:Smooth Muscle Myosins / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D011794:Quercetin; D009219:Myosin-Light-Chain Kinase; D017301:Ca(2+) Mg(2+)-ATPase; D024745:Smooth Muscle Myosins; D004642:Emodin