Document Type: Research article
Applied Physiology Research Center and Dept. of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Achillea wilhelmsii have been used in folk remedies. The relaxant effects of the extract
of A. wilhelmsii on tracheal chains of guinea pigs were examined. The relaxant effects of
four cumulative concentrations of the extract, theophylline and saline were examined by
their relaxant effects on precontracted tracheal chains of guinea pig by KCl (group 1), 10 μM
methacholine (group 2), incubated tissues by atropine, propranolol and chlorpheniramine and
contracted by KCl (group 3) and incubated tissues by propranolol and chlorpheniramine and
contracted by methacholine (group 4). In group 1 and 2, all concentrations of theophylline
and three higher concentrations (4, 6 and 8 mg/mL) of the extract showed significant relaxant
effects compared to that of saline. In groups 3 and 4 experiments also all concentrations of
the extract showed significant relaxant effects compared to that of saline. The relaxant effect
of three higher concentrations (4, 6 and 8 mg/mL) of the extract in group 1 were significantly
greater 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 for
theophylline in groups 1 and 2 and the extract in all four groups of experiments. These results
showed a potent relaxant effect for the extract from A. wilhelmsii on tracheal chains of guinea
pigs. A muscarinc receptor blockade was also suggested for the extract.