Kaempferol Inhibits Colonic Contractions via L‑Type Voltage-Dependent Calcium Channels in Murine Smooth Muscle Cells

Kaempferol, a natural flavonoid in various herbs, exhibits many therapeutical effects of anti-inflammation, antitumor, antioxidation, and so on. While its therapeutic potential has been established in many diseases, Kaempferol's side effect on colonic motility and the underlying mechanism remains ambiguous. The colonic muscle strips from ICR mice were used in contractile experiments to explore the effects of Kaempferol on colonic contractions. Besides, a whole-cell patch technique was performed on the lysed cells from the colonic muscles to investigate the underlying mechanism of Kaempferol's inhibitory effects. It was found that Kaempferol could inhibit the contractions of colonic smooth muscle significantly. However, blocking the effect of the enteric nervous system or interstitial cells could not block the inhibitory effect of Kaempferol on colonic contractions. Besides, the agonist of the L-type calcium channel Bay K8644 could suppress the inhibiting effect of Kaempferol on colonic contractions. The whole-cell patch of smooth muscle cells shows that the Kaempferol inhibited the Ba currents via the L-type calcium channel. In conclusion, Kaempferol suppresses colonic contractions by inhibiting the L-type calcium channel in a smooth muscle cell, independent of enteric neurons, chloride channels, or potassium channels, which indicates its potential effects on colonic motility and underlying mechanisms.