Abstract: [Objective] To investigate the effects of Apocynum venetum water extract （AVWE） on gastrointestinal motility in mice and provide a scientific reference for the rational use of Apocynum venetum-based products. [Methods] A two-fold increasing concentration test, single-concentration test, and combined administration with a muscarinic receptor （M-receptor） agonist were conducted to evaluate the effects of AVWE on isolated small intestinal segments in mice. Mice were intragastrically administered 5, 25, 125 g/L AVWE or saline, followed by ink suspension, to calculate intestinal propulsion rates and ink retention rates in four equally divided segments of the small intestine. [Results] Compared with pre-treatment values, two-fold increasing concentrations of AVWE （0.5-8.0 g/L） could reduce the contractile tension and amplitude of isolated intestine. A single concentration of AVWE （4.0 g/L） highly significantly （P<0.01） decreased contractile tension and amplitude to （74.5±2.2）% and （82.0±2.6）% of pre-treatment levels, respectively. The peak contraction percentage of intestine treated with AVWE combined with the M-receptor agonist bethanechol chloride （BCh） [（180.8±6.4）%] was extremely significantly （P<0.01） higher than that with Tyrode’s solution combined with BCh [（158.1±4.7）%]. AVWE administration dose-dependently reduced intestinal propulsion rate, with ink predominantly retained in the third part of the small intestine. [Conclusion] AVWE inhibits gastrointestinal motility in mice, and its suppressive effect on intestinal motility may be independent of M-receptor antagonism.

Key words: Apocynum venetum, mice, small intestine, intestinal propulsion rate, M-receptor