Butylidenephthalide Blocks Potassium Channels and Enhances Basal Tension in Isolated Guinea-Pig Trachea

الملخص EN

Butylidenephthalide (Bdph, 30~300 μM), a constituent of Ligusticum chuanxiong Hort., significantly enhanced tension in isolated guinea-pig trachea.

In this study, we investigate the mechanism(s) of Bdph-induced contraction in the tissue.

Isolated trachea was bathed in 5 mL of Krebs solution containing indomethacin (3 μM), and its tension changes were isometrically recorded.

Cromakalim (3 μM), an ATP-dependent K+ channel opener, significantly antagonized the Bdph-induced enhancement of baseline tension.

Bdph (300 μM) also significantly antagonized cromakalim-induced relaxation.

Bdph (300 μM) did not significantly influence the antagonistic effects of glibenclamide (GBC, 1 μM) and tetraethylammonium (TEA, 8 mM) against the cromakalim-induced relaxation.

However, Bdph (300 μM) and 4-aminopiridine (4-AP, 5 mM), a blocker of Kv1 family of K+ channels, in combination significantly rightward shifted the log concentration-relaxation curve of cromakalim.

The antagonistic effect of the combination almost equals the sum of the individual effects of Bdph and 4-AP, suggesting that the antagonistic mechanism of Bdph may be similar to that of 4-AP.

All calcium channel blockers influenced neither the baseline tension nor antagonistic effect of Bdph against cromakalim.

In conclusion, Bdph may be similar to 4-AP, a blocker of Kv1 family of K+ channels, to enhance the baseline tension of guinea-pig trachea.