The effect of extracellular glutamate release on repetitive transient ischemic injury in global ischemia model.
During operations, neurosurgeons usually perform multiple temporary occlusions of parental artery, possibly resulting in 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 study, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion (VO) model to compare between single occlusion and repeated transient occlusions within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. From real time monitoring of glutamate release in 11 VO model, the change of extracellular glutamate level in repeated transient occlusion group was smaller than that of single occlusion group, and the onset time of glutamate release in the second ischemic episode of repeated occlusion group was delayed compared to the first ischemic episode which was similar to that of single 10 min ischemic episode. These results suggested that repeated transient occlusion induces less glutamate release from neuronal cell than single occlusion, and the delayed onset time of glutamate release is attributed to endogeneous protective mechanism of ischemic tolerance.
Lee
Gi Ja
GJ
Department of Biomedical Engineering, School of Medicine, Kyunghee University, Seoul 130-702, Korea.
Choi
Seok Keun
SK
Eo
Yun Hye
YH
Kang
Sung Wook
SW
Choi
Samjin
S
Park
Jeong Hoon
JH
Lim
Ji Eun
JE
Hong
Kyung Won
KW
Jin
Hyun Seok
HS
Oh
Berm Seok
BS
Park
Hun Kuk
HK