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Hydrogen peroxide differentially affects activity in the pre-Bötzinger complex and hippocampus
Alfredo J Garcia1, Shakil A Khan, Ganesh K Kumar
1Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Ave., Seattle, WA, USA. alfredo.garcia@seattlechildrens.org
Journal of Neurophysiology
|August 19, 2011
Summary
Hydrogen peroxide (H(2)O(2)) differentially affects neuronal activity in neonatal mouse brain regions. While it augments respiratory rhythm in the pre-Bötzinger complex, it suppresses hippocampal CA1 activity, indicating region-specific modulation by reactive oxygen species.
Area of Science:
- Neuroscience
- Cellular Physiology
- Oxidative Stress Biology
Background:
- Reactive oxygen species (ROS) are critical signaling molecules influencing neuronal function.
- Hydrogen peroxide (H(2)O(2)) is a key ROS implicated in modulating neuronal excitability.
- Understanding the specific effects of H(2)O(2) on different neuronal populations is crucial for comprehending brain function and dysfunction.
Purpose of the Study:
- To investigate the differential effects of hydrogen peroxide (H(2)O(2)) on neuronal activity in the pre-Bötzinger complex (preBötC) and the CA1 hippocampal region of neonatal mice.
- To elucidate the mechanisms underlying H(2)O(2)-induced changes in neuronal activity, including the role of iron and lipid peroxidation.
Main Methods:
- Electrophysiological recordings were used to assess neuronal activity in the preBötC and CA1 regions.
- H(2)O(2) was applied exogenously to modulate neuronal activity.
- Iron chelators and iron were used in conjunction with H(2)O(2) to explore mechanistic pathways.
- Malondialdehyde (MDA) levels were measured as an indicator of lipid peroxidation.
Main Results:
- H(2)O(2) caused a transient depression followed by augmentation of neuronal activity in the preBötC, with iron influencing the depression phase.
- H(2)O(2) suppressed neuronal activity in the CA1 region, an effect potentiated by iron, suggesting hydroxyl radical involvement.
- Lipid peroxidation, indicated by MDA levels, was unaltered in the preBötC but significantly increased in the CA1 region.
Conclusions:
- Exogenous H(2)O(2) exerts distinct effects on neuronal activity in the preBötC and CA1 regions.
- H(2)O(2) acts as a significant modulator of respiratory rhythmogenesis originating from the preBötC without altering the global oxidative status.
- The findings highlight the complex, region-specific roles of ROS in neuronal function and the potential involvement of Fenton chemistry in the hippocampus.
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