title: Monitoring extracellular glutamate in hippocampal slices with a microsensor.
abstract: The direct local assessment of glutamate in brain slices may improve our understanding of glutamatergic neurotransmission significantly. However, an analytical technique that monitors glutamate directly in brain slices is currently not available. Most recording techniques either monitor derivatives of glutamate or detect glutamate that diffuses out of the slice. Microsensors provide a promising solution to fulfill this analytical requirement. In the present study we have implanted a 10 microm diameter hydrogel-coated microsensor in the CA1 area of hippocampal slices to monitor extracellular glutamate levels. The influence of several pharmacological agents, which facilitate glutamate release from neurons or astrocytes, was investigated to explore the applicability of the microsensor. It was observed that KCl, veratradine, alpha-latrotoxine (LTX), DL-threo-beta-benzyloxyaspartate (dl-TBOA) and L-cystine rapidly increased the extracellular glutamate levels. As far as we know this is the first study in which a microsensor is applied to monitor dynamic changes of glutamate in brain slices and in our opinion this type of research may contribute greatly to improve our understanding of the physiology of glutamatergic neurotransmission.
authors.affiliation: Department of Biomonitoring and Sensoring, University Center for Pharmacy, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands. w.h.oldenziel@rug.nl
authors.forename: W H
authors.initials: WH
authors.lastname: Oldenziel
authors.forename: M
authors.initials: M
authors.lastname: van der Zeyden
authors.forename: G
authors.initials: G
authors.lastname: Dijkstra
authors.forename: W E J M
authors.initials: WE
authors.lastname: Ghijsen
authors.forename: H
authors.initials: H
authors.lastname: Karst
authors.forename: T I F H
authors.initials: TI
authors.lastname: Cremers
authors.forename: B H C
authors.initials: BH
authors.lastname: Westerink
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D001681:Biological Assay / Q000295:instrumentation / Q000379:methods*; D004347:Drug Interactions; D045604:Extracellular Fluid / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000032:analysis* / Q000378:metabolism* / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D015336:Molecular Probe Techniques / Q000295:instrumentation; D014179:Neurotransmitter Uptake Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D026941:Sodium Channel Blockers / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology
chemical_list: D014179:Neurotransmitter Uptake Inhibitors; D026941:Sodium Channel Blockers; C120673:benzyloxyaspartate; D001224:Aspartic Acid; D018698:Glutamic Acid; D014701:Veratridine