The Spasmolytic Effect of Astragalus Sarcocolla on the Intestinal Smooth Muscles of Rabbit In Vitro: Potassium Channel Opening

Introduction Astragalus species have been widely used in Chinese herbal medicine to treat gastrointestinal and inflammatory disorders. This study was conducted to evaluate the efficacy of Astragalus sarcocolla (ASE) and to rationalize its medicinal use as an antispasmodic drug for the treatment of spasmodic gastrointestinal and inflammatory disorders associated with increased intestinal motility. Methods The ethanolic extract of ASE was studied to examine its antispasmodic effect on the isolated rabbit ileum preparations, and the contractions were recorded on PowerLab (ADInstruments, Sydney, Australia). Results ASE was able to inhibit spontaneous ileum contractions. It also completely inhibited K(+) (25 mM)-induced contractions but was unable to inhibit high K(+) (80 mM)-induced sustained contractions. Pretreatment of the tissue with glibenclamide, a potassium channel blocker, caused a rightward shift of the dose-response curve when stimulated with K(+) (25 mM) in the presence of an increasing concentration of the extract. Verapamil at very low doses inhibited both the 25 mM and 80 mM K(+)-induced contractions. Conclusion The results of our study demonstrated the spasmolytic activity of ASE with the potential mechanism of activation of K(+)ATP, which provides a strong basis for its medicinal use in motility and inflammatory disorders of the intestine.