Microdialysis Studies of Seizure-Induced Oxidative Stress

描述（由申请人提供）：本项目旨在探讨癫痫发作在氧化应激中的作用。大量研究表明，癫痫发作会导致活性氧和活性氮（ROS和RNS）的形成，从而导致DNA、脂质和蛋白质的氧化损伤。在癫痫发作期间的兴奋毒性事件和随后形成的ROS和RNS导致氧化应激的作用将被研究。在离散的大脑区域进行微透析取样，同时记录皮质电图（ECoG）活动，将用于探测与癫痫发作相关的大脑化学和电图活动的变化。这将提供将生物标志物水平与癫痫活动相关联的能力。微透析取样将用于

DESCRIPTION (provided by applicant): The purpose of this project is to investigate the role of epileptic seizures in oxidative stress. There is a wealth of research that demonstrates that epileptic seizures lead to the formation of reactive oxygen and nitrogen species (ROS and RNS), which cause oxidative damage to DNA, lipids, and proteins. The role of excitotoxic events during epileptic seizures and the subsequent formation of ROS and RNS leading to oxidative stress will be investigated. Microdialysis sampling in discrete brain regions along with simultaneous recording of electrocorticographic (ECoG) activity will be used to probe chemical and electrographic activity changes in the brain associated with seizures. This will provide the ability to correlate biomarker levels with seizure activity. Microdialysis sampling will be used to continuously monitor several biochemical pathways prior to, during, and after induction of seizures. Microdialysis experiments will provide both temporal and spatial information about oxidative stress caused by seizures and the brains response to them. This approach will provide insight into questions that have remained unclear using plasma and urine sampling and standard tissue sampling techniques. Methods previously developed in the PI's laboratory will be used to monitor formation of ROS and RNS, biomarkers for DNA damage and lipid peroxidation, and the neurotransmitter amino acids and catecholamines. A new analytical method will be developed to detect prostanoids resulting from arachidonic acid metabolism. Three experimental models of epilepsy will be used in Wistar rats. The first two models use 3-mercaptopropionic acid (3-MPA) to chemically induce seizures in a controlled manner. For one model the 3-MPA is systemically administered and in the other it is locally administered through the microdialysis probe. A chemical kindling model will then be used, where a sub-threshold dose (for triggering seizures) of pentylenetetrazol will be used to generate seizures of increasing intensity, culminating in a generalized seizure convulsion. In addition, we propose to investigate the role of various modulation agents on the release of known oxidative stress agents during epileptic seizures. Using microdialysis sampling coupled to the advanced analytical methodology, the neurological events leading from seizures to oxidative stress will be investigated. In particular, the temporal relationship between oxidative stress (as measured by ROS and RNS formation), and neuroexcitation (as measured by the GABA/glutamate ratio and the catecholamines) will be determined and correlated to the duration and intensity of seizure episodes.