Lack of Anticholinergic Activity by Baicalin in the Isolated Trachea of Guinea Pig

Abstract

The anticholinergic effect of baicalin on the trachea from asthmatic guinea pig had been described elsewhere. Using 1 × 10^-5 M bethanechol to induce contraction in the isolated trachea from non-asthmatic guinea pig, baicalin below 1 × 10^-4 M was unable to attenuate the bethanechol-induced tracheal contraction; however, 1 × 10^-4 M baicalin was demonstrated to increase the tracheal contraction in the presence of bethanechol. Baicalin (1 × 10^-4 M) was also able to induce tracheal contraction in the absence of bethanechol, and this baicalin-induced tracheal contraction was shown to be atropine-sensitive. These data suggested that the baicalin effect on the isolated trachea from non-asthmatic guinea pig was not anticholinergic in nature.