pCPT cAMP did not suppress intracellular superoxide production induced by six OHDA The accumulation of ROS is reported to play an vital part during the six OHDA induced apoptosis Berman and Hastings, 1999; Choi et al 1999; Double et al 1998; He et al 2000; Salinas et al 2003 . To acquire even further insight into the mechanism with the intracellular generation of ROS, we employed the superoxide mediated oxidation of hydroethidine to ethidium Yamada et al 2003b and straight assessed the relative rate of superoxide anion generation. As proven in Inhibitor 10A, the fluorescence intensity of ethidium was greater by the treatment method with six OHDA in a time dependent manner. The maximize in fluorescence intensity was observed from 2min just after therapy with 50 M 6 OHDA Inhibitor 10A . The fluorescence change was suppressed by tiron, a scavenger of intracellular superoxide Zuo et al 2000 , but not by pCPTcAMP Figs. 10B and C . Moreover, tiron also suppressed the 6 OHDA induced p38 phosphorylation, membrane depolarization and chromatin condensation Inhibitor eleven .
A greater concentration and longer pretreatment of tiron resulted in the far more obvious inhibition from the membrane depolarization and chromatin condensation Figs. 11D and E . These effects indicate the generation of intracellular ROS, quite possibly superoxide, is essential for that 6 OHDA induced apoptosis, and that six OHDA induced CsA insensitive mitochondrial membrane depolarization occurred through the nonspecific p38 MAPK Inhibitors membrane damage induced by ROS. 3. Inhibitor Inside the existing work, we demonstrated that 6 OHDA induced apoptosis was dependent on superoxide production, and was inhibited by pCPT cAMP in PC12 cells. The reduce in mitochondrial membrane probable was not inhibited by pCPT cAMP and was not more likely to be involved inside the apoptosis machinery in this model. It has been reported that six OHDA induces MPT in isolated brain mitochondria Kim et al 2001 . In isolated rat liver mitochondria, we also detected that six OHDA induces cytochrome c release by means of a CMPT mechanism, which showed mitochondrial swelling and membrane depolarization with a CsA delicate mechanism information not proven .
In the total PC12 cells, read full report then again, 6 OHDA induced mitochondrial membrane depolarization and chromatin condensation had been not inhibited by CsA Inhibitor four . These success indicate that CMPT, which characterized by depolarization and swelling in a CsA delicate mechanism, is not concerned inside the mechanism of apoptosis Di Paola et al 2006 . Presumably, the lessen in mitochondrial membrane prospective was rather a outcome of cell death. In this context, we observed that tiron, and that is a superoxide scavenger, but not pCPT cAMP, suppressed the 6 OHDA induced mitochondrial membrane depolarization and superoxide generation Figs. 10B and 11B and D .