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Arias HR, Kazmierska-Grebowska P, Kowalczyk T, Shim Y, Caban B, Aman C, Allain AE, De Deurwaerdère P, Chagraoui A. Coronaridine congeners induce anticonvulsant activity in rodents by hippocampal mechanisms involving mainly potentiation of GABA A receptors. Eur J Pharmacol 2024; 982:176911. [PMID: 39179091 DOI: 10.1016/j.ejphar.2024.176911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/29/2024] [Accepted: 08/15/2024] [Indexed: 08/26/2024]
Abstract
The coronaridine congeners catharanthine and 18-methoxycoronaridine (18-MC) display sedative, anxiolytic, and antidepressant properties by acting on mechanisms involving GABAergic and/or monoaminergic transmissions. Here, we expanded their pharmacological properties by studying their anticonvulsant activity in male and female mice using the pentylenetetrazole (PTZ)-induced seizure test. To determine potential neurochemical mechanisms, the effect of congeners on monoamine content and kainic acid (KA)-induced epileptiform discharge was studied in the hippocampus. The behavioral results showed that coronaridine congeners induce acute anticonvulsant activity in a dose-dependent but sex-independent manner. Repeated treatment with a subthreshold dose (20 mg/kg) of each congener produced anticonvulsant activity in a sex-independent manner, but was significantly higher in male mice when compared to its acute effect. Using a behaviourally relevant regimen, we found that PTZ increased dopamine metabolites and serotonin tissue content. Coronaridine congeners, which induced distinct effects on monoamines, blunted the effect of PTZ instead of potentiating it, suggesting the existence of another mechanism in their anticonvulsant activity. The electrophysiological results indicated that both congeners inhibit KA-induced epileptiform discharges in hippocampal slices. A key aspect of this study is that the activity of both congeners was observed only in the presence of GABA, supporting the notion that hippocampal GABAAR potentiation plays an important role. Our study showed that coronaridine congeners induce acute anticonvulsant activity in a sex-independent manner. However, a comparatively higher susceptibility was observed in male mice after repeated treatment. The underlying hippocampal mechanisms mainly involve GABAAR potentiation, whereas monoamines play a minor role in the anticonvulsive action.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, OK, USA
| | | | - Tomasz Kowalczyk
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Yaeun Shim
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Bartosz Caban
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Chloé Aman
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Anne-Emilie Allain
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Abdeslam Chagraoui
- Department of Medical Biochemistry, Rouen University Hospital, CHU de Rouen, France; Laboratory of Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Inserm UMR 1239, University Rouen Normandie, 76000 Rouen, France; Normandie University, UNIROUEN, Institute for Research and Innovation in Biomedicine of Normandy (IRIB) Rouen, France.
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Lamotrigine Attenuates Neuronal Excitability, Depresses GABA Synaptic Inhibition, and Modulates Theta Rhythms in Rat Hippocampus. Int J Mol Sci 2021; 22:ijms222413604. [PMID: 34948401 PMCID: PMC8705017 DOI: 10.3390/ijms222413604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/29/2021] [Accepted: 12/05/2021] [Indexed: 12/03/2022] Open
Abstract
Theta oscillations generated in hippocampal (HPC) and cortical neuronal networks are involved in various aspects of brain function, including sensorimotor integration, movement planning, memory formation and attention. Disruptions of theta rhythms are present in individuals with brain disorders, including epilepsy and Alzheimer’s disease. Theta rhythm generation involves a specific interplay between cellular (ion channel) and network (synaptic) mechanisms. HCN channels are theta modulators, and several medications are known to enhance their activity. We investigated how different doses of lamotrigine (LTG), an HCN channel modulator, and antiepileptic and neuroprotective agent, would affect HPC theta rhythms in acute HPC slices (in vitro) and anaesthetized rats (in vivo). Whole-cell patch clamp recordings revealed that LTG decreased GABAA-fast transmission in CA3 cells, in vitro. In addition, LTG directly depressed CA3 and CA1 pyramidal neuron excitability. These effects were partially blocked by ZD 7288, a selective HCN blocker, and are consistent with decreased excitability associated with antiepileptic actions. Lamotrigine depressed HPC theta oscillations in vitro, also consistent with its neuronal depressant effects. In contrast, it exerted an opposite, enhancing effect, on theta recorded in vivo. The contradictory in vivo and in vitro results indicate that LTG increases ascending theta activating medial septum/entorhinal synaptic inputs that over-power the depressant effects seen in HPC neurons. These results provide new insights into LTG actions and indicate an opportunity to develop more precise therapeutics for the treatment of dementias, memory disorders and epilepsy.
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Urbanska M, Kazmierska-Grebowska P, Kowalczyk T, Caban B, Nader K, Pijet B, Kalita K, Gozdz A, Devijver H, Lechat B, Jaworski T, Grajkowska W, Sadowski K, Jozwiak S, Kotulska K, Konopacki J, Van Leuven F, van Vliet EA, Aronica E, Jaworski J. GSK3β activity alleviates epileptogenesis and limits GluA1 phosphorylation. EBioMedicine 2018; 39:377-387. [PMID: 30502054 PMCID: PMC6355642 DOI: 10.1016/j.ebiom.2018.11.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/16/2018] [Accepted: 11/16/2018] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Glycogen synthase kinase-3β (GSK3β) is a key regulator of cellular homeostasis. In neurons, GSK3β contributes to the control of neuronal transmission and plasticity, but its role in epilepsy remains to be defined. METHODS Biochemical and electrophysiological methods were used to assess the role of GSK3β in regulating neuronal transmission and epileptogenesis. GSK3β activity was increased genetically in GSK3β[S9A] mice. Its effects on neuronal transmission and epileptogenesis induced by kainic acid were assessed by field potential recordings in mice brain slices and video electroencephalography in vivo. The ion channel expression was measured in brain samples from mice and followed by analysis in samples from patients with temporal lobe epilepsy or focal cortical dysplasia in correlation to GSK3β phosphorylation. FINDINGS Higher GSK3β activity decreased the progression of kainic acid induced epileptogenesis. At the biochemical level, higher GSK3β activity increased the expression of hyperpolarization-activated cyclic nucleotide-gated (HCN) channel 4 under basal conditions and in the epileptic mouse brain and decreased phosphorylation of the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 at Serine 831 under basal conditions. Moreover, we found a significant correlation between higher inhibitory GSK3β phosphorylation at Serine 9 and higher activating GluA1 phosphorylation at Serine 845 in brain samples from epileptic patients. INTERPRETATION Our data imply GSK3β activity in the protection of neuronal networks from hyper-activation in response to epileptogenic stimuli and indicate that the anti-epileptogenic function of GSK3β involves modulation of HCN4 level and the synaptic AMPA receptors pool.
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Affiliation(s)
- Malgorzata Urbanska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland; Department of Neurology and Epileptology, Children's Memorial Health Institute, Warsaw 04-730, Poland.
| | - Paulina Kazmierska-Grebowska
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz 90-236, Poland
| | - Tomasz Kowalczyk
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz 90-236, Poland
| | - Bartosz Caban
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz 90-236, Poland
| | - Karolina Nader
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw 02-093, Poland
| | - Barbara Pijet
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw 02-093, Poland
| | - Katarzyna Kalita
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw 02-093, Poland
| | - Agata Gozdz
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland
| | - Herman Devijver
- Experimental Genetics Group - LEGTEGG, Department of Human Genetics, KULeuven, Leuven 3000, Belgium
| | - Benoit Lechat
- Experimental Genetics Group - LEGTEGG, Department of Human Genetics, KULeuven, Leuven 3000, Belgium
| | - Tomasz Jaworski
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw 02-093, Poland
| | - Wieslawa Grajkowska
- Department of Pathology, Children's Memorial Health Institute, Warsaw 04-730, Poland
| | - Krzysztof Sadowski
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Warsaw 04-730, Poland
| | - Sergiusz Jozwiak
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Warsaw 04-730, Poland; Department of Child Neurology, Medical University of Warsaw, Warsaw 02-091, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Warsaw 04-730, Poland
| | - Jan Konopacki
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz 90-236, Poland
| | - Fred Van Leuven
- Experimental Genetics Group - LEGTEGG, Department of Human Genetics, KULeuven, Leuven 3000, Belgium
| | - Erwin A van Vliet
- Amsterdam UMC, University of Amsterdam, Department of (Neuro) Pathology, Amsterdam Neuroscience, Amsterdam, the Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, 1098 XH, the Netherlands
| | - Eleonora Aronica
- Amsterdam UMC, University of Amsterdam, Department of (Neuro) Pathology, Amsterdam Neuroscience, Amsterdam, the Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
| | - Jacek Jaworski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
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Bocian R, Caban B, Kłos-Wojtczak P, Konopacki J, Kowalczyk T. Is electrical coupling involved in the generation of posterior hypothalamic theta rhythm? Eur J Neurosci 2016; 44:2324-33. [DOI: 10.1111/ejn.13338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 07/06/2016] [Accepted: 07/13/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Renata Bocian
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143 90-236 Lodz Poland
| | - Bartosz Caban
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143 90-236 Lodz Poland
| | - Paulina Kłos-Wojtczak
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143 90-236 Lodz Poland
| | - Jan Konopacki
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143 90-236 Lodz Poland
| | - Tomasz Kowalczyk
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143 90-236 Lodz Poland
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Bocian R, Kłos-Wojtczak P, Caban B, Kowalczyk T, Kaźmierska P, Konopacki J. Cell discharge correlates of posterior hypothalamic theta rhythm recorded in anesthetized rats and brain slices. Hippocampus 2016; 26:1354-69. [DOI: 10.1002/hipo.22612] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2016] [Indexed: 02/05/2023]
Affiliation(s)
- Renata Bocian
- Department of Neurobiology; the University of Łódź; Pomorska Str. No 141/143 Łódź 91-236 Poland
| | - Paulina Kłos-Wojtczak
- Department of Neurobiology; the University of Łódź; Pomorska Str. No 141/143 Łódź 91-236 Poland
| | - Bartosz Caban
- Department of Neurobiology; the University of Łódź; Pomorska Str. No 141/143 Łódź 91-236 Poland
| | - Tomasz Kowalczyk
- Department of Neurobiology; the University of Łódź; Pomorska Str. No 141/143 Łódź 91-236 Poland
| | - Paulina Kaźmierska
- Department of Neurobiology; the University of Łódź; Pomorska Str. No 141/143 Łódź 91-236 Poland
| | - Jan Konopacki
- Department of Neurobiology; the University of Łódź; Pomorska Str. No 141/143 Łódź 91-236 Poland
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Kalweit AN, Yang H, Colitti-Klausnitzer J, Fülöp L, Bozsó Z, Penke B, Manahan-Vaughan D. Acute intracerebral treatment with amyloid-beta (1-42) alters the profile of neuronal oscillations that accompany LTP induction and results in impaired LTP in freely behaving rats. Front Behav Neurosci 2015; 9:103. [PMID: 25999827 PMCID: PMC4422036 DOI: 10.3389/fnbeh.2015.00103] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/07/2015] [Indexed: 11/30/2022] Open
Abstract
Accumulation of amyloid plaques comprises one of the major hallmarks of Alzheimer’s disease (AD). In rodents, acute treatment with amyloid-beta (Aβ; 1–42) elicits immediate debilitating effects on hippocampal long-term potentiation (LTP). Whereas LTP contributes to synaptic information storage, information is transferred across neurons by means of neuronal oscillations. Furthermore, changes in theta-gamma oscillations, that appear during high-frequency stimulation (HFS) to induce LTP, predict whether successful LTP will occur. Here, we explored if intra-cerebral treatment with Aβ(1–42), that prevents LTP, also results in alterations of hippocampal oscillations that occur during HFS of the perforant path-dentate gyrus synapse in 6-month-old behaving rats. HFS resulted in LTP that lasted for over 24 h. In Aβ-treated animals, LTP was significantly prevented. During HFS, spectral power for oscillations below 100 Hz (δ, θ, α, β and γ) was significantly higher in Aβ-treated animals compared to controls. In addition, the trough-to-peak amplitudes of theta and gamma cycles were higher during HFS in Aβ-treated animals. We also observed a lower amount of envelope-to-signal correlations during HFS in Aβ-treated animals. Overall, the characteristic profile of theta-gamma oscillations that accompany successful LTP induction was disrupted. These data indicate that alterations in network oscillations accompany Aβ-effects on hippocampal LTP. This may comprise an underlying mechanism through which disturbances in synaptic information storage and hippocampus-dependent memory occurs in AD.
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Affiliation(s)
- Alexander Nikolai Kalweit
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany ; International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany
| | - Honghong Yang
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany ; International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany
| | | | - Livia Fülöp
- Department of Medical Chemistry, University of Szeged Szeged, Hungary
| | - Zsolt Bozsó
- Department of Medical Chemistry, University of Szeged Szeged, Hungary
| | - Botond Penke
- Department of Medical Chemistry, University of Szeged Szeged, Hungary
| | - Denise Manahan-Vaughan
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany ; International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany
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Bocian R, Kazmierska P, Kłos-Wojtczak P, Kowalczyk T, Konopacki J. Orexinergic theta rhythm in the rat hippocampal formation: In vitro and in vivo findings. Hippocampus 2015; 25:1393-406. [PMID: 25820995 DOI: 10.1002/hipo.22459] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2015] [Indexed: 02/02/2023]
Abstract
Previous in vivo data suggested that orexin neuropeptides (ORX(A) and ORX(B) ) synthetized in hypothalamic neurons were involved in the mechanism of generation of the hippocampal formation theta rhythm. Surprisingly, this suggestion has never been directly proved by experiments using intraseptal or intrahippocampal administration of orexins. In this study, involving the use of in vitro hippocampal formation slices and in vivo model of anesthetized rat, we provide the first convergent electropharmacological evidence that in the presence of both ORX(A) and ORX(B) the hippocampal formation neuronal network is capable of producing oscillations in the theta band. This effect of orexin peptides was antagonized by selective blockers of orexin receptors (OX1 R and OX2 R), SB 334867 and TCS OX2 29, respectively. These results provide evidence for a novel, orexinergic mechanism responsible for the production of theta rhythm in the hippocampal formation neuronal network.
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Affiliation(s)
- Renata Bocian
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Poland
| | - Paulina Kazmierska
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Poland
| | - Paulina Kłos-Wojtczak
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Poland
| | - Tomasz Kowalczyk
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Poland
| | - Jan Konopacki
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Poland
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Kowalczyk T, Bocian R, Caban B, Konopacki J. Atropine-sensitive theta rhythm in the posterior hypothalamic area: in vivo and in vitro studies. Hippocampus 2013; 24:7-20. [PMID: 23836546 DOI: 10.1002/hipo.22167] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/11/2013] [Accepted: 06/24/2013] [Indexed: 11/06/2022]
Abstract
Theta rhythm is the largest, most prominent, and well-documented electroencephalography activity present in a number of mammals, including humans. Spontaneous theta activity recorded locally in the posterior hypothalamic area (PHa) has never been the subject of detailed studies. The authors have shown that local theta field potentials could be generated in urethane-anesthetized rats in the supramammillary (SuM) nuclei and posterior hypothalamic (PH) nuclei. Theta recorded in the PHa was produced independently of simultaneously occurring hippocampal theta. These data were confirmed in the PHa maintained in vitro. Local theta field activity was recorded in the SuM and PH nuclei of PHa slice preparations perfused with cholinergic agonist carbachol. Both in vivo and in vitro recorded PHa theta rhythmicity had a cholinergic-muscarinic profile, that is, it was antagonized by muscarinic antagonist atropine sulfate.
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Affiliation(s)
- Tomasz Kowalczyk
- Department of Neurobiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
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Kowalczyk T, Bocian R, Konopacki J. The generation of theta rhythm in hippocampal formation maintainedin vitro. Eur J Neurosci 2012; 37:679-99. [DOI: 10.1111/ejn.12091] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 11/09/2012] [Accepted: 11/12/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Tomasz Kowalczyk
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143; 90-236; Lodz; Poland
| | - Renata Bocian
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143; 90-236; Lodz; Poland
| | - Jan Konopacki
- Department of Neurobiology; Faculty of Biology and Environmental Protection; University of Lodz; Pomorska Str. No 141/143; 90-236; Lodz; Poland
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Kazmierska P, Grebowski J, Konopacki J. Does an anti-oxidant ascorbic acid improve the condition of hippocampal formation slice preparations? A micro-EEG approach. Int J Exp Pathol 2012; 93:406-13. [PMID: 23083000 DOI: 10.1111/j.1365-2613.2012.00838.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 07/01/2012] [Indexed: 11/29/2022] Open
Abstract
The objective of this study was to assess whether ascorbic acid (AA), an intracellular anti-oxidant critical for neuronal protection, when added to artificial cerebrospinal fluid (ACSF), is able to protect hippocampal (HPC) formation slice preparations from ageing. In this research, the micro-electroencephalographic (EEG) technique was applied. Experiments were performed on 72 HPC formation slices obtained from 12 male Wistar rats. Two series of experiments were conducted: the control experiment, in which ACSF was used as an incubation medium, and the research one, in which ACSF was supplemented with 200 μM AA. The experimental model of carbachol-induced EEG theta rhythm was applied. The following parameters of theta rhythm after 15, 30 and 45 min of recording were analysed: frequency, power, time duration of theta epochs and time duration of intervals between theta epochs. The results show that AA causes a statistically significant decrease in the power of theta rhythm after 15, 30 and 45 min of recording. The time duration of intervals between theta epochs was almost twice as long in slices incubated in ACSF + AA than in ACSF after 45 min of recording. The data obtained indicate that AA does not improve the condition of HPC slices. On the contrary, it worsens the ability of slice preparations to generate theta oscillations. We hypothesize that our data may result from the Fenton reaction or changes in the conformation of connexins.
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Kowalczyk T, Konopacki J, Bocian R, Caban B. Theta-related gating cells in hippocampal formation: In vivo and in vitro study. Hippocampus 2012; 23:30-9. [DOI: 10.1002/hipo.22050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2012] [Indexed: 02/05/2023]
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Gillis JA, Zhang L, Skinner FK. Spatial coherence and stationarity of local field potentials in an isolated whole hippocampal preparation in vitro. J Comput Neurosci 2010; 29:521-32. [PMID: 20082133 DOI: 10.1007/s10827-009-0207-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 12/17/2009] [Accepted: 12/22/2009] [Indexed: 11/26/2022]
Abstract
Local field potential (LFP) multielectrode recordings of spontaneous rhythms in an isolated whole hippocampal preparation are characterized with respect to their spatial variability within the hippocampus, and their frequency properties. Using simulated data, we categorize potential relationships between frequency variation over time in LFP recordings and spatial variability between electrodes. We then use data recorded from the intact preparation to distinguish between our theoretical categories. We find that the LFP recordings have a close to spatially invariant frequency distribution (not phase) across the hippocampus, and differ in frequency only in a component that may be seen as physiological noise. From these facts, we conclude that the isolated hippocampal LFP recordings represent a single signal and may be regarded as a unitary circuitry. We additionally examine phase differences across our recording sites. We use our characterization of the hippocampal isolate's properties to predict its spatial coherence in response to high frequency stimulation. We find that there is a finely tuned inverse relationship between temporal variability in the hippocampal isolate's LFP recordings and their spatial coherence.
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Affiliation(s)
- Jesse A Gillis
- Toronto Western Research Institute, University Health Network, Toronto, Canada.
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