Rotenone induces KATP channel opening in PC12 cells in association with the expression of tyrosine hydroxylase

The activation of ATP-sensitive potassium (K-ATP) channels in PC12 cells play a pivotal role in protection against the neurotoxic effect of rotenone. However, it remains unclear why rotenone seems to preferentially affect activation of K-ATP channels and if this could affect its physiological activity. In this study, we sought to determine how the different energy states caused by various doses of rotenone affect the K-ATP opening state and whether the K-ATP opening state influences the expression of tyrosine hydroxylase (TH) which is related with DA synthesis. With patch clamp technology, results showed that treatment of PC12 cells with rotenone (0.2-1 mu g/ml) for 15 min can cause K-ATP channel opening with significantly increased intracellular ROS production. Treatment with rotenone (2-16 ng/ml) for 24 h also caused the channels to open with gently increased ROS. In order to study if the rather long-term action on K-ATP channel opening states could affect the specified function of PC12 cells, the K-ATP channel opener pinacidil and the inhibitor glibenclamide were used to treat cells for 24 h, and the expression of TH was detected. Our results showed that treatment of PC12 cells with glibenclamide for 24 h can notably promote TH expression and can also enhance the expression of TH which were reduced by rotenone. These data indicate that the energy states in PC12 induced by various doses of rotenone could significantly influence the opening states of K-ATP channels. However long-term energy stress may raise the opening rate and opening sensitivity of this channel. In addition, our results demonstrate for the first time that activation of plasma membrane K-ATP channels induced by rotenone inhibits TH expression which influences DA synthesis in PC12 cells.