Inhibitory effects of peony root extract on the large conductance calcium-activated potassium current essential in production of bursting activity.

To elucidate the mechanism of inhibitory action of peony root extract on pentylenetetrazol-induced bursting activity, effects of peony root extract on the iberiotoxin-sensitive large conductance calcium-activated potassium (BKCa) current that plays an essential role in the production of bursting activity were investigated. Peony root extract showed a clear inhibitory effect on the iberiotoxin-sensitive calcium-activated potassium current. Peony root extract also showed clear inhibitory effects on spontaneous bursting activity and BKCa current in the cerebral cortical neurons of the EL mouse, a hereditary epilepsy animal model. These results together with our previous studies, including the protective effect against neuron damage, indicate that peony root extract is a promising herbal drug for inhibition of convulsions.