1
|
Modarres Mousavi SM, Alipour F, Noorbakhsh F, Jafarian M, Ghadipasha M, Gharehdaghi J, Kellinghaus C, Speckmann EJ, Stummer W, Khaleghi Ghadiri M, Gorji A. Clinical Correlation of Altered Molecular Signatures in Epileptic Human Hippocampus and Amygdala. Mol Neurobiol 2024; 61:725-752. [PMID: 37658249 PMCID: PMC10861640 DOI: 10.1007/s12035-023-03583-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/14/2023] [Indexed: 09/03/2023]
Abstract
Widespread alterations in the expression of various genes could contribute to the pathogenesis of epilepsy. The expression levels of various genes, including major inhibitory and excitatory receptors, ion channels, cell type-specific markers, and excitatory amino acid transporters, were assessed and compared between the human epileptic hippocampus and amygdala, and findings from autopsy controls. Moreover, the potential correlation between molecular alterations in epileptic brain tissues and the clinical characteristics of patients undergoing epilepsy surgery was evaluated. Our findings revealed significant and complex changes in the expression of several key regulatory genes in both the hippocampus and amygdala of patients with intractable epilepsy. The expression changes in various genes differed considerably between the epileptic hippocampus and amygdala. Different correlation patterns were observed between changes in gene expression and clinical characteristics, depending on whether the patients were considered as a whole or were subdivided. Altered molecular signatures in different groups of epileptic patients, defined within a given category, could be viewed as diagnostic biomarkers. Distinct patterns of molecular changes that distinguish these groups from each other appear to be associated with epilepsy-specific functional consequences.
Collapse
Affiliation(s)
| | - Fatemeh Alipour
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Farshid Noorbakhsh
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Maryam Jafarian
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Masoud Ghadipasha
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran
| | - Jaber Gharehdaghi
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran
| | | | - Erwin-Josef Speckmann
- Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Walter Stummer
- Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | | | - Ali Gorji
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran.
- Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Münster, Germany.
- Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Münster, Germany.
- Department of Neuroscience, Mashhad University of Medical Sciences, Mashhad, Iran.
| |
Collapse
|
2
|
Rosen JB, Schulkin J. Hyperexcitability: From Normal Fear to Pathological Anxiety and Trauma. Front Syst Neurosci 2022; 16:727054. [PMID: 35993088 PMCID: PMC9387392 DOI: 10.3389/fnsys.2022.727054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
Hyperexcitability in fear circuits is suggested to be important for development of pathological anxiety and trauma from adaptive mechanisms of fear. Hyperexcitability is proposed to be due to acquired sensitization in fear circuits that progressively becomes more severe over time causing changing symptoms in early and late pathology. We use the metaphor and mechanisms of kindling to examine gains and losses in function of one excitatory and one inhibitory neuropeptide, corticotrophin releasing factor and somatostatin, respectively, to explore this sensitization hypothesis. We suggest amygdala kindling induced hyperexcitability, hyper-inhibition and loss of inhibition provide clues to mechanisms for hyperexcitability and progressive changes in function initiated by stress and trauma.
Collapse
Affiliation(s)
- Jeffrey B. Rosen
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
- *Correspondence: Jeffrey B. Rosen,
| | - Jay Schulkin
- School of Medicine, University of Washington, Seattle, WA, United States
| |
Collapse
|
3
|
Faraz M, Kosarmadar N, Rezaei M, Zare M, Javan M, Barkley V, Shojaei A, Mirnajafi-Zadeh J. Deep brain stimulation effects on learning, memory and glutamate and GABA A receptor subunit gene expression in kindled rats. Acta Neurobiol Exp (Wars) 2021; 81:43-57. [PMID: 33949168 DOI: 10.21307/ane-2021-006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 01/14/2021] [Indexed: 11/11/2022]
Abstract
Epileptic seizures are accompanied by learning and memory impairments. In this study, the effect of low frequency stimulation (LFS) on spatial learning and memory was assessed in kindled animals and followed for one month. Fully kindled rats received LFS at 4 times (immediately, 6 h, 24 h and 30 h following the final kindling stimulation). Applying LFS improved kindled animals' performance in the Barnes maze test. This LFS action was accompanied by a decrease in NR2B gene expression, an increase in the gene expression of the α subunit of calcineurin A and an increased NR2A/NR2B ratio in kindled animals. In addition, the gene expression of the GABAA receptor γ2 subunit increased at 2-3 h after applying LFS. The increase in NR2A/NR2B ratio was also observed 1 week after LFS. No significant changes were observed one month after LFS administration. Field potential recordings in the hippocampal CA1 area showed that kindling-induced potentiation of the field EPSP slope returned to near baseline when measured 2-3 h after applying LFS. Therefore, it may be postulated that applying LFS in kindled animals reduced the seizure-induced learning and memory impairments, albeit time-dependently. In tandem, LFS prevented kindling-induced alterations in gene expression of the described proteins, which are potentially important for synaptic transmission and/or potentiation. Moreover, a depotentiation-like phenomenon may be a possible mechanism underlying the LFS action. Epileptic seizures are accompanied by learning and memory impairments. In this study, the effect of low frequency stimulation (LFS) on spatial learning and memory was assessed in kindled animals and followed for one month. Fully kindled rats received LFS at 4 times (immediately, 6 h, 24 h and 30 h following the final kindling stimulation). Applying LFS improved kindled animals’ performance in the Barnes maze test. This LFS action was accompanied by a decrease in NR2B gene expression, an increase in the gene expression of the α subunit of calcineurin A and an increased NR2A/NR2B ratio in kindled animals. In addition, the gene expression of the GABAA receptor γ2 subunit increased at 2–3 h after applying LFS. The increase in NR2A/NR2B ratio was also observed 1 week after LFS. No significant changes were observed one month after LFS administration. Field potential recordings in the hippocampal CA1 area showed that kindling-induced potentiation of the field EPSP slope returned to near baseline when measured 2–3 h after applying LFS. Therefore, it may be postulated that applying LFS in kindled animals reduced the seizure-induced learning and memory impairments, albeit time-dependently. In tandem, LFS prevented kindling-induced alterations in gene expression of the described proteins, which are potentially important for synaptic transmission and/or potentiation. Moreover, a depotentiation-like phenomenon may be a possible mechanism underlying the LFS action.
Collapse
Affiliation(s)
- Mona Faraz
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Nastaran Kosarmadar
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Mahmoud Rezaei
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Meysam Zare
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Mohammad Javan
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran ; Institute for Brain Sciences and Cognition , Tarbiat Modares University , Tehran , Iran
| | - Victoria Barkley
- Krembil Research Institute , University Health Network , Toronto , Canada
| | - Amir Shojaei
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran ; Institute for Brain Sciences and Cognition , Tarbiat Modares University , Tehran , Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran ; Institute for Brain Sciences and Cognition , Tarbiat Modares University , Tehran , Iran
| |
Collapse
|
4
|
Wellmann M, Álvarez-Ferradas C, Maturana CJ, Sáez JC, Bonansco C. Astroglial Ca 2+-Dependent Hyperexcitability Requires P2Y 1 Purinergic Receptors and Pannexin-1 Channel Activation in a Chronic Model of Epilepsy. Front Cell Neurosci 2018; 12:446. [PMID: 30542266 PMCID: PMC6277884 DOI: 10.3389/fncel.2018.00446] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 11/06/2018] [Indexed: 12/31/2022] Open
Abstract
Astrocytes from the hippocampus of chronic epileptic rats exhibit an abnormal pattern of intracellular calcium oscillations, characterized by an augmented frequency of long lasting spontaneous Ca2+ transients, which are sensitive to purinergic receptor antagonists but resistant to tetrodotoxin. The above suggests that alterations in astroglial Ca2+-dependent excitability observed in the epileptic tissue could arise from changes in astrocyte-to-astrocyte signaling, which is mainly mediated by purines in physiological and pathological conditions. In spite of that, how purinergic signaling contributes to astrocyte dysfunction in epilepsy remains unclear. Here, we assessed the possible contribution of P2Y1R as well as pannexin1 and connexin43 hemichannels—both candidates for non-vesicular ATP-release—by performing astroglial Ca2+ imaging and dye uptake experiments in hippocampal slices from control and fully kindled rats. P2Y1R blockade with MRS2179 decreased the mean duration of astroglial Ca2+ oscillations by reducing the frequency of slow Ca2+ transients, and thereby restoring the balance between slow (ST) and fast transients (FT) in the kindled group. The potential contribution of astroglial pannexin1 and connexin43 hemichannels as pathways for purine release (e.g., ATP) was assessed through dye uptake experiments. Astrocytes from kindled hippocampi exhibit three-fold more EtBr uptake than controls, whereby pannexin1 hemichannels (Panx1 HCs) accounts for almost all dye uptake with only a slight contribution from connexin43 hemichannels (Cx43 HCs). Confirming its functional involvement, Panx1 HCs inhibition decreased the mean duration of astroglial Ca2+ transients and the frequency of slow oscillations in kindled slices, but had no noticeable effects on the control group. As expected, Cx43 HCs blockade did not have any effects over the mean duration of astroglial Ca2+ oscillations. These findings suggest that P2Y1R and Panx1 HCs play a pivotal role in astroglial pathophysiology, which would explain the upregulation of glutamatergic neurotransmission in the epileptic brain and thus represents a new potential pharmacological target for the treatment of drug-refractory epilepsy.
Collapse
Affiliation(s)
- Mario Wellmann
- Centro de Neurobiología y Plasticidad Cerebral CNPC, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Escuela de Fonoaudiología, Facultad de Medicina, Universidad de Valparaíso, Valparaíso, Chile
| | - Carla Álvarez-Ferradas
- Centro de Neurobiología y Plasticidad Cerebral CNPC, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Escuela de Ciencias de la Salud, Universidad Viña del Mar, Valparaíso, Chile
| | - Carola J Maturana
- Departamento de Ciencias Fisiológicas, Facultad Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Juan C Sáez
- Departamento de Ciencias Fisiológicas, Facultad Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Christian Bonansco
- Centro de Neurobiología y Plasticidad Cerebral CNPC, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| |
Collapse
|
5
|
Burgdorf J, Kroes RA, Zhang XL, Gross AL, Schmidt M, Weiss C, Disterhoft JF, Burch RM, Stanton PK, Moskal JR. Rapastinel (GLYX-13) has therapeutic potential for the treatment of post-traumatic stress disorder: Characterization of a NMDA receptor-mediated metaplasticity process in the medial prefrontal cortex of rats. Behav Brain Res 2015. [PMID: 26210936 DOI: 10.1016/j.bbr.2015.07.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Rapastinel (GLYX-13) is a NMDA receptor modulator with glycine-site partial agonist properties. It is a robust cognitive enhancer and shows rapid and long-lasting antidepressant properties in both animal models and in humans. Contextual fear extinction (CFE) in rodents has been well characterized and used extensively as a model to study the neurobiological mechanisms of post-traumatic stress disorder (PTSD). Since CFE is NMDA receptor modulated and neural circuitry in the medial prefrontal cortex (MPFC) regulates both depression and PTSD, studies were undertaken to examine the effects of rapastinel for its therapeutic potential in PTSD and to use rapastinel as a tool to study its underlying glutamatergic mechanisms. A 21-day chronic mild unpredictable stress (CUS) rat model was used to model depression and PTSD. The effects of CUS alone compared to No CUS controls, and the effects of rapastinel (3 mg/kg IV) on CUS-treated animals were examined. The effect of rapastinel was first assessed using CUS-treated rats in three depression models, Porsolt, sucrose preference, and novelty-induced hypophagia tests, and found to produce a complete reversal of the depressive-like state in each model. Rapastinel was then assessed in a MPFC-dependent positive emotional learning paradigm and in CFE and again a reversal of the impairments induced by CUS treatment was observed. Both synaptic plasticity and metaplasticity, as measured by the induction of long-term potentiation in rat MPFC slice preparations, was found to be markedly impaired in CUS-treated animals. This impairment was reversed when CUS-treated rats were administered rapastinel and tested 24 h later. Transcriptomic analysis of MPFC mRNA expression in CUS-treated rats corroborated the link between rapastinel's behavioral effects and synaptic plasticity. A marked enrichment in both the LTP and LTD connectomes in rapastinel-treated CUS rats was observed compared to CUS-treated controls. The effects of rapastinel on depression models, PEL, and most importantly on CFE demonstrate the therapeutic potential of rapastinel for the treatment of PTSD. Moreover, rapastinel appears to elicit its therapeutic effects through a NMDA receptor-mediated, LTP-like, metaplasticity process in the MPFC.
Collapse
Affiliation(s)
- Jeffrey Burgdorf
- Falk Center for Molecular Therapeutics, Department of Biomedical Engineering, Northwestern University, 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA
| | - Roger A Kroes
- Naurex Inc., 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA
| | - Xiao-lei Zhang
- Department of Cell Biology & Anatomy, Basic Sciences Building, Rm. 217, New York Medical College, Valhalla, NY 10595, USA
| | - Amanda L Gross
- Naurex Inc., 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA
| | - Mary Schmidt
- Naurex Inc., 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA
| | - Craig Weiss
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Ward Building 7-140, Chicago, IL 6061, USA
| | - John F Disterhoft
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Ward Building 7-140, Chicago, IL 6061, USA
| | - Ronald M Burch
- Naurex Inc., 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA
| | - Patric K Stanton
- Department of Cell Biology & Anatomy, Basic Sciences Building, Rm. 217, New York Medical College, Valhalla, NY 10595, USA
| | - Joseph R Moskal
- Falk Center for Molecular Therapeutics, Department of Biomedical Engineering, Northwestern University, 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA; Naurex Inc., 1801 Maple Ave., Suite 4300, Evanston, IL 60201, USA.
| |
Collapse
|
6
|
Morales JC, Alvarez-Ferradas C, Roncagliolo M, Fuenzalida M, Wellmann M, Nualart FJ, Bonansco C. A new rapid kindling variant for induction of cortical epileptogenesis in freely moving rats. Front Cell Neurosci 2014; 8:200. [PMID: 25100948 PMCID: PMC4107828 DOI: 10.3389/fncel.2014.00200] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 07/03/2014] [Indexed: 11/29/2022] Open
Abstract
Kindling, one of the most used models of experimental epilepsy is based on daily electrical stimulation in several brain structures. Unlike the classic or slow kindling protocols (SK), the rapid kindling types (RK) described until now require continuous stimulation at suprathreshold intensities applied directly to the same brain structure used for subsequent electrophysiological and immunohistochemical studies, usually the hippocampus. However, the cellular changes observed in these rapid protocols, such as astrogliosis and neuronal loss, could be due to experimental manipulation more than to epileptogenesis-related alterations. Here, we developed a new RK protocol in order to generate an improved model of temporal lobe epilepsy (TLE) which allows gradual progression of the epilepsy as well as obtaining an epileptic hippocampus, thus avoiding direct surgical manipulation and electric stimulation over this structure. This new protocol consists of basolateral amygdala (BLA) stimulation with 10 trains of biphasic pulses (10 s; 50 Hz) per day with 20 min-intervals, during 3 consecutive days, using a subconvulsive and subthreshold intensity, which guarantees tissue integrity. The progression of epileptic activity was evaluated in freely moving rats through electroencephalographic (EEG) recordings from cortex and amygdala, accompanied with synchronized video recordings. Moreover, we assessed the effectiveness of RK protocol and the establishment of epilepsy by evaluating cellular alterations of hippocampal slices from kindled rats. RK protocol induced convulsive states similar to SK protocols but in 3 days, with persistently lowered threshold to seizure induction and epileptogenic-dependent cellular changes in amygdala projection areas. We concluded that this novel RK protocol introduces a new variant of the chronic epileptogenesis models in freely moving rats, which is faster, highly reproducible and causes minimum cell damage with respect to that observed in other experimental models of epilepsy.
Collapse
Affiliation(s)
- Juan Carlos Morales
- Centro de Neurobiología y Plasticidad Cerebral, Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso Valparaíso, Chile
| | - Carla Alvarez-Ferradas
- Centro de Neurobiología y Plasticidad Cerebral, Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso Valparaíso, Chile
| | - Manuel Roncagliolo
- Centro de Neurobiología y Plasticidad Cerebral, Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso Valparaíso, Chile
| | - Marco Fuenzalida
- Centro de Neurobiología y Plasticidad Cerebral, Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso Valparaíso, Chile
| | - Mario Wellmann
- Centro de Neurobiología y Plasticidad Cerebral, Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso Valparaíso, Chile
| | - Francisco Javier Nualart
- Laboratorio de Neurobiología y Células Madre, Departamento de Biología Celular, Universidad de Concepción Concepción, Chile
| | - Christian Bonansco
- Centro de Neurobiología y Plasticidad Cerebral, Facultad de Ciencias, Instituto de Fisiología, Universidad de Valparaíso Valparaíso, Chile
| |
Collapse
|
7
|
Botterill JJ, Fournier NM, Guskjolen AJ, Lussier AL, Marks WN, Kalynchuk LE. Amygdala kindling disrupts trace and delay fear conditioning with parallel changes in Fos protein expression throughout the limbic brain. Neuroscience 2014; 265:158-71. [PMID: 24486965 DOI: 10.1016/j.neuroscience.2014.01.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/09/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Amygdala kindling is well known to increase unconditioned fear and anxiety. However, relatively little is known about whether this form of kindling causes functional changes within the neural circuitry that mediates fear learning and the retrieval of fear memories. To address this issue, we examined the effect of short- (i.e., 30 stimulations) and long-term (i.e., 99 stimulations) amygdala kindling in rats on trace and delay fear conditioning, which are aversive learning tasks that rely predominantly on the hippocampus and amygdala, respectively. After memory retrieval, we analyzed the pattern of neural activity with Fos, the protein product of the immediate early gene c-fos. We found that kindling had no effect on acquisition of the trace fear conditioning task but it did selectively impair retrieval of this fear memory. In contrast, kindling disrupted both acquisition and retrieval of fear memory in the delay fear conditioning task. We also found that kindling-induced impairments in memory retrieval were accompanied by decreased Fos expression in several subregions of the hippocampus, parahippocampus, and amygdala. Interestingly, decreased freezing in the trace conditioning task was significantly correlated with dampened Fos expression in hippocampal and parahippocampal regions whereas decreased freezing in the delay conditioning task was significantly correlated with dampened Fos expression in hippocampal, parahippocampal, and amygdaloid circuits. Overall, these results suggest that amygdala kindling promotes functional changes in brain regions involved in specific types of fear learning and memory.
Collapse
Affiliation(s)
- J J Botterill
- Department of Psychology, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada
| | - N M Fournier
- Department of Psychiatry, Yale University School of Medicine, Yale University, New Haven, CT 06508, USA
| | - A J Guskjolen
- Department of Psychology, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada
| | - A L Lussier
- Department of Psychology, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada
| | - W N Marks
- Department of Psychology, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada
| | - L E Kalynchuk
- Department of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada.
| |
Collapse
|
8
|
Integrative biological analysis for neuropsychopharmacology. Neuropsychopharmacology 2014; 39:5-23. [PMID: 23800968 PMCID: PMC3857644 DOI: 10.1038/npp.2013.156] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 01/24/2023]
Abstract
Although advances in psychotherapy have been made in recent years, drug discovery for brain diseases such as schizophrenia and mood disorders has stagnated. The need for new biomarkers and validated therapeutic targets in the field of neuropsychopharmacology is widely unmet. The brain is the most complex part of human anatomy from the standpoint of number and types of cells, their interconnections, and circuitry. To better meet patient needs, improved methods to approach brain studies by understanding functional networks that interact with the genome are being developed. The integrated biological approaches--proteomics, transcriptomics, metabolomics, and glycomics--have a strong record in several areas of biomedicine, including neurochemistry and neuro-oncology. Published applications of an integrated approach to projects of neurological, psychiatric, and pharmacological natures are still few but show promise to provide deep biological knowledge derived from cells, animal models, and clinical materials. Future studies that yield insights based on integrated analyses promise to deliver new therapeutic targets and biomarkers for personalized medicine.
Collapse
|
9
|
Gavrilovici C, Pollock E, Everest M, Poulter MO. The loss of interneuron functional diversity in the piriform cortex after induction of experimental epilepsy. Neurobiol Dis 2012; 48:317-28. [PMID: 22801084 DOI: 10.1016/j.nbd.2012.07.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 06/28/2012] [Accepted: 07/05/2012] [Indexed: 11/20/2022] Open
Abstract
Interneuronal functional diversity is thought to be an important factor in the control of neural network oscillations in many brain regions. Specifically, interneuron action potential firing patterns are thought to modulate brain rhythms. In neurological disorders such as epilepsy where brain rhythms are significantly disturbed interneuron function is largely unexplored. Thus the purpose of this study was to examine the functional diversity of piriform cortex interneurons (PC; an area of the brain that easily supports seizures) before and after kindling-induced epilepsy. Using cluster analysis, we found five control firing behaviors. These groups were termed: non-adapting very high frequency (NAvHF), adapting high frequency (AHF), adapting low frequency (ALF), strongly adapting low frequency (sALF), and weakly adapting low frequency (wALF). A morphological analysis showed these spiking patterns were not associated with any specific interneuronal morphology although we found that most of the cells displaying NAvHF firing pattern were multipolar. After kindling about 40% of interneuronal firing pattern changed, and neither the NAvHF nor the wALF phenotypes were found. We also found that in multipolar interneurons a long-lasting potassium current was increased. A qPCR analysis indicated Kv1.6 subtype was up-regulated after kindling. An immunocytochemical analysis showed that Kv1.6 protein expression on parvalbumin (multipolar) interneurons increased by greater than 400%. We also examined whether these changes could be due to the selective death of a subset of interneurons but found that there was no change in cell number. These data show an important loss of the functional diversity of interneurons in the PC. Our data suggest that under pathophysiological condition interneurons are plastic resulting in the attenuation of high frequency network oscillations in favor of low frequency network activity. This may be an important new mechanism by which network synchrony is disturbed in epileptic seizures.
Collapse
Affiliation(s)
- Cezar Gavrilovici
- Molecular Brain Research Group, Robarts Research Institute, Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A 5K8
| | | | | | | |
Collapse
|