Further analysis on lidocaine-induced increase in intracellular Zn2+ concentration : Cytometric model study using FluoZin-3, 5-chloromethylfluorescein, and rat thymocytes

Lidocaine augmented FluoZin-3 fluorescence of rat thymocytes, suggesting the increase in intracellular Zn2+
concentration. However, the mechanism for lidocaine-induced increase in the intensity of FluoZin-3
fluorescence was not elucidated. In this study, in order to reveal the mechanism, the effects of lidocaine on
FluoZin-3 and 5-chloromethylfluorescein (5-CMF) fluorescence were examined under various conditions.
5-CMF fluorescence was used as a parameter for cellular content of nonprotein thiols. The lidocaine-induced
augmentation of FluoZin-3 fluorescence was observed under external Ca2+- and/or Zn2+-free conditions,
suggesting that lidocaine induced intracellular Zn2+ release. Lidocaine attenuated 5-CMF fluorescence,
suggesting the decrease in cellular content of nonprotein thiols. Since some peptides consisting of SH-group
have been proposed to store Zn2+, the decrease in nonprotein thiol content by