title: The effect of NMDA-R antagonism on simultaneously acquired local field potentials and tissue oxygen levels in the brains of freely-moving rats.
abstract: Non-competitive NMDA receptor antagonists are known to induce psychosis-like symptoms in rodents. Administration of such compounds cause behavioural effects such as memory impairment and hyperlocomotion. Additionally, drugs such as phencyclidine (PCP), ketamine and MK-801 all cause distinctive increases in striatal local field potential (LFP) in the high frequency oscillation (HFO) band in the power spectrum (140-180 Hz). Amperometric sensors provide a means to measure tissue oxygen (tO2; a BOLD-like signal) in the brains of freely-moving rats while simultaneously acquiring LFP using the same electrode. Carbon paste electrodes were implanted into the striatum and hippocampus of male Wistar rats. Rats were administered with saline, ketamine (10 mg/kg), MK-801 (0.1 mg/kg) and PCP (2.5 mg/kg) and recordings were made at 1 kHz using three different potentials (-650 mV to measure tO2; 0 mV and +700 mV as control conditions). NMDA receptor antagonism caused significant increases in tO2in both the striatum and the hippocampus. Power spectrum analysis showed significant increases in HFO power in the striatum but not in the hippocampus. Conversely, there were significant decreases in delta and alpha power along with increases in theta and gamma power in the hippocampus that were absent in the striatum. This supports findings that LFP can be obtained from an amperometric sensor signal; allowing simultaneous acquisition of two translational biomarkers of neuronal activity (LFP and tO2).
authors.affiliation: Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland; Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland. Electronic address: kealyjo@tcd.ie.
authors.forename: John
authors.initials: J
authors.lastname: Kealy
authors.affiliation: Department of Psychology, Maynooth University, Maynooth, Co. Kildare, Ireland.
authors.forename: Sean
authors.initials: S
authors.lastname: Commins
authors.affiliation: Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland.
authors.forename: John P
authors.initials: JP
authors.lastname: Lowry
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D058256:Brain Waves / Q000187:drug effects* / Q000502:physiology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004567:Electrodes, Implanted; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D010100:Oxygen / Q000378:metabolism*; D010622:Phencyclidine / Q000494:pharmacology; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine; D016291:Dizocilpine Maleate; D010622:Phencyclidine; D010100:Oxygen
keywords: High-frequency oscillations; Hippocampus; Ketamine; MK-801; Phencyclidine; Striatum