Real-time monitoring of glutamate transmitter release with anoxic depolarization during anoxic insult in rat striatum

In vivo continuous real-time measurement of glutamate concentration was performed during anoxia using a dialysis electrode, By this method, the temporal resolution of the measurement of glutamate concentration was improved due to shortening of the time delay compared with the microdialysis method, and changes in the glutamate concentration were more clearly represented with greater reproducibility. After exposure to anoxia, the glutamate concentration showed biphasic changes. A relationship between the DC potential and release of glutamate was confirmed by the synchronization of anoxic depolarization (AD) with the Ist phase of glutamate release. Since the Ist phase disappeared and AD was delayed and suppressed by blocking Ca2+ influx, exocytosis is considered to play an important role in the construction of the Ist phase, which had a close relation with the occurrence of AD. Moreover, since blocking Ca2+ influx also had an effect on the glutamate release from the metabolic pool (2nd phase), reversed uptake may be involved with energy failure in the Ist phase, Ca2+ influx into the cell and rapid changes of the ionic environment associated with AD. (C) 1999 Published by Elsevier Science B.V. All rights reserved.