Real Time H2O2 Imaging and Neuronal Cell Death


Nahoko Kasai, Chunxi Han, Akiyoshi Shimada, Tobias Nyberg and Keiichi Torimitsu
Materials Science Laboratory

 Hydrogen peroxide (H2O2) has been recognized in association with the pathology of neurological diseases because it is a by-product of a degenerative reaction of reactive oxygen species, one of the major causes of oxidative stress in mammalian cells. Because it is relatively stable comparing to the other reactive oxygen species, it has been used as a target molecule for detecting oxidative stress.
 Hippocampus has widely been examined and it is well understood that the epilepsy relates to the cell death in its specific regions. We have recently found that by bicuculline (Bic), GABAA receptor antagonist, also causes neuronal cell death in specific regions in hippocampus [1]. However little has been investigated on its details.
We have recently established a multichannel H2O2 monitoring system to monitor the real time H2O2 distribution in a tissue. In this study, we examined the cell death caused by Bic in terms of the oxidative stress [2].
 We fabricated the sensor array, and we monitored the real time H2O2 distribution in a cultured rat hippocampal slice placed on the array. When we introduced bicuculline into the solution as a stimulant, in the presence of a catalase inhibitor, we could observe a distinct increase in the H2O2 concentration (B) and increase in calcium influx (C) at the same regions as neuronal cell death (D). This implies that the Bic causes cell death through oxidative stress.
 This real time H2O2 distribution monitoring system will be a powerful tool with which to explore the neuronal cell death mechanism in biological systems and to manage the neuronal disorders.

[1] C. Han, N. Kasai, K. Torimitsu, NeuroReport 16 (2005) 333-336.
[2] N. Kasai, C. Han, K. Torimitsu, Sens. Act. B 107 (2005) 746-750.

Fig. By Bic application to a hippocampal slice (A), H2O2 release (B) and increase in Ca influx (C) were observed at the same region of the cell dearh (D).

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