Abstract
In our previous paper it was reported that lidocaine, procaine and dibucaine inhibited Na, K-ATPase activity and that the inhibitory effects may be related to the action of local anesthesia and its side effects. It was suggested that local anesthetics affect many proteins including Na-channel in the same manner and change their functions. In this study, the reversibility of the inhibitory activities and the inhibition mechanisms of local anesthetics were investigated to verify the previous results. The inhibition of Na, K-ATPase activity by lidocaine or procaine was reversible by decreasing the concentration of the anesthetics by dilution, but the inhibition by dibucaine was irreversible. All three anesthetics inhibited the formation of phosphointermediate in the Na, K-ATPase reaction sequence in concentration dependency similar to that in the inhibition of Na, K-ATPase activity. These results suggested that local anesthetics inhibit Na, K-ATPase activity by inhibiting phosphointermediate formation, supporting our previous report that inhibition of Na, K-ATPase activity by local anesthetics may be partially related to the mechanism of local anesthesia.
