Effects of ginsenosides on rat jejunal contractility.

CONTEXT: Ginsenosides are primary active ingredients of ginseng, which are believed to have various health benefits. It is found that the biotransformation of ginsenosides mainly takes place in the gastrointestinal tract and the information about ginsenosides-exerted effects on intestinal contractility is not sufficient. AIMS: The present study proposed that ginsenosides could exert stimulatory or inhibitory effects on intestinal motility depending on the assay condition-related intestinal contractile states and was to characterize the effects of ginsenosides on intestinal motility. METHODS: Jejunal contractility determination, Western blotting analysis, and real-time polymerase chain reaction were performed to test the effects of total ginsenosides isolated from Panax ginseng C. A. Mey (Araliaceae) root. RESULTS: The results showed that ginsenosides at the fixed concentration of 20 mg/L exerted bidirectional regulation (BR) on the contractility of isolated jejunal segment (IJS), depending on the contractile states. The contractility of IJS was increased by ginsenosides in low contractile states, which were correlated to the cholinergic activation, and the contractility of IJS was decreased by ginsenosides in high contractile states, which were correlated to the adrenergic activation and nitric oxide related mechanisms. Ginsenosides-induced BR was abolished in the absence of Ca(2+) or by using tetrodotoxin, implicating the requirement of Ca(2+) and the enteric nervous system. Effects of ginsenosides on myosin light chain phosphorylation and the mRNA expression of myosin light chain kinase were also bidirectional. DISCUSSION AND CONCLUSION: Results suggest that ginsenosides may have the potential clinical implication for reliving the symptoms of alternative hypo- and hyper-intestinal motility.