The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Mechanisms of relaxant action of luteolin in isolated guinea pig trachea.

We have investigated the mechanisms of action of luteolin, a flavone found in Perilla frutescens, a Chinese herbal medicine for treating asthma. In fact, luteolin occurs mostly as a glycoside in many plant species. The tension changes of tracheal segments were isometrically recorded on a polygraph. Luteolin concentration-dependently relaxed histamine (30 microM)-, carbachol (0.2 microM)- and KCl (30 mM)-induced precontractions, and inhibited cumulative histamine- and carbachol-induced contractions in a non-competitive manner. Luteolin also concentration-dependently and non-competitively inhibited cumulative Ca2+-induced contractions in depolarized (K+, 60 mM) guinea-pig trachealis. The nifedipine (10 microM)-remaining tension of histamine (30 microM)-induced precontractions was further relaxed by luteolin, suggesting that no matter whether VDCCs were blocked or not, luteolin may have other mechanisms of relaxant action. The relaxant effect of luteolin was unaffected by the removal of epithelium or by the presence of propranolol (1 microM), 2',5'-dideoxyadenosine (10 microM), methylene blue (25 microM), glibenclamide (10 microM), Nomega-nitro-L-arginine (20 microM), or alpha-chymotrypsin (1 U/mL). However, luteolin (10-20 microM) produced parallel and leftward shifts of the concentration-response curve of forskolin or nitroprusside. Luteolin or IBMX at various concentrations (10-300 microM) concentration-dependently and significantly inhibited cAMP- and cGMP-PDE activities of the trachealis. The IC50 values of luteolin were estimated to be 32.4 and 34.6 microM, respectively. IBMX at various concentrations (10-300 microM) selectively inhibited neither cAMP-, nor cGMP-PDE activity. In contrast to IBMX, luteolin at 100 and 300 microM more potently (P < 0.05) inhibited cGMP-, than cAMP-PDE activity. The above results indicate that the mechanisms of relaxant action of luteolin may be due to its inhibitory effects on both PDE activities and its reduction on [Ca2+]i of the trachealis.[1]


  1. Mechanisms of relaxant action of luteolin in isolated guinea pig trachea. Ko, W.C., Shih, C.M., Leu, I.J., Chen, T.T., Chang, J.P. Planta Med. (2005) [Pubmed]
WikiGenes - Universities