title: Simultaneous monitoring of excitatory postsynaptic potentials and extracellular L-glutamate in mouse hippocampal slices.
abstract: Simultaneous monitoring of amperometric currents at a glass capillary sensor based on recombinant GluOx and field excitatory postsynaptic potentials (fEPSPs) were performed in region CA1 of mouse hippocampal slices. A transient increase in the glutamate current relative to the basal one at control stimulation (0.052Hz) was evoked by stimulation at 2 Hz for 2 min. The magnitude of the glutamate current was dependent on the intensity (current) of a 2 Hz stimulus and reflected the slope of the fEPSP. The in situ calibration of the L-glutamate sensor revealed that the extracellular concentration of L-glutamate released by 2 Hz stimulation before tetanus is in the range from 0.8 to 2.2 μM and it is enhanced after tetanic stimulation. The L-glutamate level at a test stimulus (0.052 Hz) was estimated to be 32 nM. The recombinant GluOx-based sensor exhibited weak responses to glutamine above 300 μM and L-aspartic acid above 200 μM. The potential use of a glass capillary sensor in combination with fEPSP measurements for electrophysiological study is discussed.
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajuosui, Setagayaku, Tokyo 156-8550, Japan.
authors.forename: Shizuko
authors.initials: S
authors.lastname: Hozumi
authors.forename: Kana
authors.initials: K
authors.lastname: Ikezawa
authors.forename: Atushi
authors.initials: A
authors.lastname: Shoji
authors.forename: Ayumi
authors.initials: A
authors.lastname: Hirano-Iwata
authors.forename: Tim
authors.initials: T
authors.lastname: Bliss
authors.forename: Masao
authors.initials: M
authors.lastname: Sugawara
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D056547:CA1 Region, Hippocampal / Q000378:metabolism / Q000502:physiology*; D004558:Electric Stimulation; D055724:Electrophysiological Phenomena; D004800:Enzymes, Immobilized; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism; D005949:Glucose Oxidase; D018698:Glutamic Acid / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008991:Monitoring, Physiologic / Q000379:methods
chemical_list: D004800:Enzymes, Immobilized; D018698:Glutamic Acid; D005949:Glucose Oxidase