Second-by-Second Measures of l-Glutamate in the Prefrontal Cortex and Striatum of Freely Moving Mice

l-Glutamate (Glu) is the main excitatory neurotransmitter in the mammalian central nervous system, and it is involved in most aspects of normal brain function, including cognition, memory and learning, plasticity, and motor movement. Although microdialysis techniques have been used to study Glu, the slow temporal resolution of the technique may be inadequate to properly examine tonic and phasic Glu. Thus, our laboratory has developed an enzyme-based microelectrode array (MEA) with fast response time and low detection limits for Glu. We have modified the MEA design to allow for reliable measures in the brain of awake, freely moving mice. In this study, we chronically implanted the MEA in prefrontal cortex (PFC) or striatum (Str) of awake, freely moving C57BL/6 mice. We successfully measured Glu levels 7 days postimplantation without loss of MEA sensitivity. In addition, we determined resting (tonic) Glu levels to be 3.3 μM in the PFC and 5.0 μM in the Str. Resting Glu levels were subjected to pharmacological manipulation with tetrodotoxin (TTX) and dl-threo-β-hydroxyaspartate (THA). TTX significantly (p < 0.05) decreased resting Glu by 20%, whereas THA significantly (p < 0.05) increased resting Glu by 60%. Taken together, our data show that chronic recordings of tonic and phasic clearance of exogenously applied Glu can be carried out in awake mice for at least 7 days in vivo, allowing for longer term studies of Glu regulation.

[1]  Francois Pomerleau,et al.  Chronic second‐by‐second measures of l‐glutamate in the central nervous system of freely moving rats , 2007, Journal of neurochemistry.

[2]  K. Moxon,et al.  Ceramic-based multisite microelectrodes for electrochemical recordings. , 2000, Analytical chemistry.

[3]  Greg A. Gerhardt,et al.  Ceramic-based multisite microelectrode arrays for in vivo electrochemical recordings of glutamate and other neurochemicals , 2003 .

[4]  Koji Hara,et al.  Anesthetic Pharmacology International Society for Anaesthetic Pharmacology the Anesthetic Mechanism of Urethane: the Effects on Neurotransmitter-gated Ion Channels , 2022 .

[5]  P. Magistretti,et al.  Effects of glial glutamate transporter inhibitors on intracellular Na+ in mouse astrocytes , 2001, Brain Research.

[6]  B. Westerink,et al.  Brain microdialysis of GABA and glutamate: What does it signify? , 1997, Synapse.

[7]  C. A. Marsden,et al.  Measurement of neurotransmitter release in vivo , 1984 .

[8]  H. Yoshino,et al.  Purification and Properties of a New Enzyme, L-Glutamate Oxidase, from Streptomyces sp. X-119-6 Grown on Wheat Bran , 1983 .

[9]  G. Gerhardt,et al.  Microelectrode array studies of basal and potassium‐evoked release of l‐glutamate in the anesthetized rat brain , 2006, Journal of neurochemistry.

[10]  S. Rossell,et al.  One-second time resolution brain microdialysis in fully awake rats. Protocol for the collection, separation and sorting of nanoliter dialysate volumes. , 2003, Journal of chromatography. B, Analytical technologies in the biomedical and life sciences.

[11]  Robert T Kennedy,et al.  In vivo neurochemical monitoring by microdialysis and capillary separations. , 2002, Current opinion in chemical biology.

[12]  Greg A. Gerhardt,et al.  Second-by-Second Measures of L-Glutamate and Other Neurotransmitters Using Enzyme-Based Microelectrode Arrays , 2007 .

[13]  G. Kinney,et al.  Prolonged physiological entrapment of glutamate in the synaptic cleft of cerebellar unipolar brush cells. , 1997, Journal of neurophysiology.

[14]  M. Kakeyama,et al.  Toluene induces rapid and reversible rise of hippocampal glutamate and taurine neurotransmitter levels in mice. , 2007, Toxicology letters.

[15]  N. Danbolt.  Glutamate uptake , 2001, Progress in Neurobiology.

[16]  Babu Subramanyam,et al.  MONITORING MOLECULES IN NEUROSCIENCE , 1991 .

[17]  M. Souweidane,et al.  Prolonged Convection-enhanced Delivery into the Rat Brainstem , 2003, Neurosurgery.

[18]  F. Pomerleau,et al.  Real Time in Vivo Measures of l‐Glutamate in the Rat Central Nervous System Using Ceramic‐Based Multisite Microelectrode Arrays , 2003, Annals of the New York Academy of Sciences.

[19]  F. Pomerleau,et al.  Age-related changes in the dynamics of potassium-evoked L-glutamate release in the striatum of Fischer 344 rats , 2004, Journal of Neural Transmission.

[20]  G. Di Chiara,et al.  Estimation of in-vivo neurotransmitter release by brain microdialysis: the issue of validity. , 1996, Behavioural pharmacology.

[21]  Hua Yang,et al.  Voltammetric study of extracellular dopamine near microdialysis probes acutely implanted in the striatum of the anesthetized rat , 2005, Journal of Neuroscience Methods.

[22]  Haley K Holmer,et al.  High and low responders to novelty show differential effects in striatal glutamate , 2005, Synapse.

[23]  Haley K Holmer,et al.  Dietary restriction affects striatal glutamate in the MPTP‐induced mouse model of nigrostriatal degeneration , 2005, Synapse.

[24]  Colin N. Dewey,et al.  Initial sequencing and comparative analysis of the mouse genome. , 2002 .

[25]  N. Kulagina,et al.  Monitoring glutamate and ascorbate in the extracellular space of brain tissue with electrochemical microsensors. , 1999, Analytical chemistry.

[26]  G. S. Wilson,et al.  Direct measurement of glutamate release in the brain using a dual enzyme-based electrochemical sensor , 1994, Brain Research.

[27]  Zheng-Xiong Xi,et al.  The Origin and Neuronal Function of In Vivo Nonsynaptic Glutamate , 2002, The Journal of Neuroscience.

[28]  P. Rada,et al.  Glutamate measured by 6-s resolution brain microdialysis: capillary electrophoretic and laser-induced fluorescence detection application. , 1997, Journal of chromatography. B, Biomedical sciences and applications.

[29]  G. Gerhardt,et al.  Self-referencing ceramic-based multisite microelectrodes for the detection and elimination of interferences from the measurement of L-glutamate and other analytes. , 2001, Analytical chemistry.

[30]  Lawrence K Duffy,et al.  An ultrastructural analysis of tissue surrounding a microdialysis probe , 1999, Journal of Neuroscience Methods.

[31]  Mi-Sook Won,et al.  Functionalized conducting polymer as an enzyme-immobilizing substrate: an amperometric glutamate microbiosensor for in vivo measurements. , 2005, Analytical chemistry.

[32]  B. Westerink,et al.  In vivo monitoring of extracellular glutamate in the brain with a microsensor , 2006, Brain Research.

[33]  P. Kalivas,et al.  Regulation of Extracellular Glutamate in the Prefrontal Cortex: Focus on the Cystine Glutamate Exchanger and Group I Metabotropic Glutamate Receptors , 2005, Journal of Pharmacology and Experimental Therapeutics.

[34]  E. Pehek,et al.  Sampling glutamate and GABA with microdialysis: suggestions on how to get the dialysis membrane closer to the synapse , 2004, Journal of Neuroscience Methods.

[35]  C. Meshul,et al.  l-dopa-induced reversal in striatal glutamate following partial depletion of nigrostriatal dopamine with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine , 2005, Neuroscience.

[36]  A. Michael,et al.  Electrochemical Methods for Neuroscience , 2006 .

[37]  Francois Pomerleau,et al.  Improved ceramic-based multisite microelectrode for rapid measurements of l-glutamate in the CNS , 2002, Journal of Neuroscience Methods.

[38]  R. Kennedy,et al.  High temporal resolution monitoring of glutamate and aspartate in vivo using microdialysis on-line with capillary electrophoresis with laser-induced fluorescence detection. , 1997, Analytical chemistry.

[39]  R. Swanson,et al.  Differing effects of substrate and non‐substrate transport inhibitors on glutamate uptake reversal , 2001, Journal of neurochemistry.

[40]  M. Récasens,et al.  Transient increase in the high affinity [3H]-l-glutamate uptake activity during in vitro development of hippocampal neurons in culture , 2001, Neurochemistry International.