title: Temperature- and concentration-dependence of kainate-induced γ oscillation in rat hippocampal slices under submerged condition.
abstract: OBJECTIVE
  Fast neuronal network oscillation at the γ frequency band (γ oscillation: 30-80 Hz) has been studied extensively in hippocampal slices under interface recording condition. The aim of this study is to establish a method for recording γ oscillation in submerged hippocampal slices that allows simultaneously monitoring γ oscillation and the oscillation-related intracellular events, such as intracellular Ca(2+) concentration or mitochondrial membrane potentials.
  
  
  METHODS
  Horizontal hippocampal slices (thickness: 300 μm) of adult rats were prepared and placed in a submerged or an interface chamber. Extracellular field recordings were made in the CA3c pyramidal layer of the slices. Kainate, an AMPA/kainate receptor agonist, was applied via perfusion. Data analysis was performed off-line.
  
  
  RESULTS
  Addition of kainate (25-1000 nmol/L) induced γ oscillation in both the submerged and interface slices. Kainate increased the γ power in a concentration-dependent manner, but the duration of steady state oscillation was reduced at higher concentrations of kainate. Long-lasting γ oscillation was maintained at the concentrations of 100-300 nmol/L. Under submerged condition, γ oscillation was temperature-dependent, with the maximum power achieved at 29 °C. The induction of γ oscillation under submerged condition also required a fast rate of perfusion (5-7 mL/min) and showed a fast dynamic during development and after the washout.
  
  
  CONCLUSIONS
  The kainite-induced γ oscillation recorded in submerged rat hippocampal slices is useful for studying the intracellular events related to neuronal network activities and may represent a model to reveal the mechanisms underlying the normal neuronal synchronizations and diseased conditions.
authors.affiliation: Department of Automation, Institute of Electrical Engineering, Yanshan University, Qinhuangdao, China. cblu@ysu.edu.cn
authors.forename: Cheng-biao
authors.initials: CB
authors.lastname: Lu
authors.forename: Zhi-hua
authors.initials: ZH
authors.lastname: Wang
authors.forename: Yan-hong
authors.initials: YH
authors.lastname: Zhou
authors.forename: Martin
authors.initials: M
authors.lastname: Vreugdenhil
mesh_terms: D000818:Animals; D004594:Electrophysiology; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology*; D007608:Kainic Acid / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018092:Kainic Acid Receptors / Q000819:agonists*; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D013696:Temperature
chemical_list: D007608:Kainic Acid; D018092:Kainic Acid Receptors