Effect of Shakuyaku-Extract on Electrical Stimulation Induced Contraction of Guinea Pig Ileum

It was reported that Paeoniae Radix extracts (S) depressed the contraction induced by electrical stimulation on the isolated guinea pig ileum. In the present study, the mechanisms of the inhibitory action of S on the contraction of guinea pig ileum were investigated. Theophylline and phentolamine are respective antagonists of adenosine and norepinephrine, decreased the inhibitory action by S on the contraction of guinea pig ileum about 50%. Thus these data suggest that some unknown substances with adrenergic and adenosine like actions may be contained in S. Furthermore the possibility of other inhibitors in S was suggested.