Real-Time Monitoring of Extracellular Glutamate Release on Repetitive IschemicInjury in Global Ischemia Model

摘要

During the operation, neurosurgeons usually perform the multiple temporary occlusions of parental artery which may induce the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this experiment, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion (VO) model during repeated occlusion within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flow metry simultaneously with cortical glutamate level measured by am-perometric biosensor. During ischemic episode, the maximum change of glutamate release was gradually decreased as 112.38 ± 26.21 uM in first period, 82.63 ± 18.50 uM in second period, and 48.58 ± 11.89 uM in third period. The time interval between the ischemia induction and the beginning of glutamate release was increased as 106.7 ± 10.89 (sec) at first attack, 139.11 ± 3.87 (sec) in second attack, 169.00 ± 14.56 (sec) in third ischemic period. From the results of real-time monitoring about glutamate release in 11 VO model during repetitive ischemic episode, it was demonstrated that repetitive ischemia induced less glutamate release from neuronal cell than single ischemia due to endogeneous protective mechanism which delayed glutamate release time in later ischemic injury.