Pharmacological studies of the effect of Dai-kenchu-to on spontaneous contraction of isolated rabbit jejunum.

We studied the effects of Dai-kenchu to on the spontaneous contraction in isolated rabbit jejunum. Dai-kenchu-to (10(-3) g/ml) increased jejunal contraction, such as phasic like contraction and contractile amplitude. Zanthoxyli Fructus (2x10(-4) g/ml) exhibited an action identical to that of Dai-kenchu-to. While Zingiberis Siccatum Rhizoma (5x10(-4) g/ml) continuously decreased the amplitude of contraction. Ginseng Radix (3x10(-4) g/ml) and Saccharum Granorum (8x10(-3) g/ml) had no effect on spontaneous contraction. Dai kenchu-to and Zanthoxyli Fructus reversed the decrease of contraction produced by atropine. However, phasic like contraction induced in the absence of atropine was antagonized by atropine. Dai-kenchu-to and Zingiberis Siccatum Rhizoma further decreased spontaneous contraction in the presence of tetrodotoxin. It was clarified that Dai-kenchu-to possesses gastroprokinetic effect, and Zanthoxyli Fructus mainly contributed to this effect. It was suggested that the cholinergic and non cholinergic nervous systems were involved in increasing intestinal motility. It was also suggested that Dai-kenchu-to acted on multiple points of the intestine, and actions at these points might intensify to improve ileus.