Possible Mechanism(s) of the Relaxant Effects of Achillea wilhelmsii on Guinea-Pig Tracheal Chains

Achillea wilhelmsii have been used in folk remedies. The relaxant effects of the extractof A. wilhelmsii on tracheal chains of guinea pigs were examined. The relaxant effects offour cumulative concentrations of the extract, theophylline and saline were examined bytheir relaxant effects on precontracted tracheal chains of guinea pig by KCl (group 1), 10 μMmethacholine (group 2), incubated tissues by atropine, propranolol and chlorpheniramine andcontracted by KCl (group 3) and incubated tissues by propranolol and chlorpheniramine andcontracted by methacholine (group 4). In group 1 and 2, all concentrations of theophyllineand three higher concentrations (4, 6 and 8 mg/mL) of the extract showed significant relaxanteffects compared to that of saline. In groups 3 and 4 experiments also all concentrations ofthe extract showed significant relaxant effects compared to that of saline. The relaxant effectof three higher concentrations (4, 6 and 8 mg/mL) of the extract in group 1 were significantlygreater than those of group 2 and in group 3 were significantly lower than those of group 1.There were significant positive correlations between the relaxant effects and concentrations fortheophylline in groups 1 and 2 and the extract in all four groups of experiments. These resultsshowed a potent relaxant effect for the extract from A. wilhelmsii on tracheal chains of guineapigs. A muscarinc receptor blockade was also suggested for the extract.