Daikenchuto, a traditional Japanese herbal medicine, promotes colonic transit by inducing a propulsive movement pattern.

Background The traditional Japanese herbal medicine, daikenchuto (DKT), has been used to treat constipation and postoperative ileus. However, the precise mechanisms involved in the pharmacological effects of DKT remain uncertain. The aim of this study was to clarify the effect of DKT on motor patterns and transit activity in the isolated rat colon. Methods The entire colon or segments of the proximal colon in rats were isolated and placed in Krebs solution. The motility of the colon was evaluated by analyzing spatiotemporal maps of diameter derived from video imaging and measuring the intraluminal pressure in the anal end of the proximal colon, and the transit time of a plastic bead through the entire isolated colon. Key Results Several types of propagating contractions were observed in the isolated entire colon. When DKT was added to Krebs solution, the frequency of large-extent anal propagating contractions increased. DKT treatment increased the intraluminal pressure in the isolated proximal colon, which was related to the propagating contractions. This effect was abolished by treatment with the neural blocker tetrodotoxin. These findings suggest DKT induced peristaltic contractions in the isolated colon. DKT accelerated colonic transit activity, which was related to peristaltic contractions induction in the colon. These effects were also observed in the colons treated with bethanechol and the active ingredient of DKT, hydroxy-alpha-sanshool. Conclusions and Inferences Daikenchuto could enhance colonic transit activity by inducing peristaltic contractions, which may be mediated by the activation of the enteric nervous system in the colon.