LACK OF ANTICHOLINERGIC ACTIVITY BY BAICALIN IN THE ISOLATED TRACHEA OF GUINEA-PIG

The anticholinergic effect of baicalin on the trachea from asthmatic g uinea pig had been described elsewhere. Using 1 x 10(-5) Wt bethanecho l to induce contraction in the isolated trachea from non-asthmatic gui nea pig, baicalin below 1 x 10(-4) M was unable to attenuate the betha nechol-induced tracheal contraction; however, 1 x 10(-4) M baicalin wa s demonstrated to increase the tracheal contraction in the presence of bethanechol. Baicalin (1 x 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 su ggested that the baicalin effect on the isolated trachea from non-asth matic guinea pig was not anticholinergic in nature.