1
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Nikitin ES, Postnikova TY, Proskurina EY, Borodinova AA, Ivanova V, Roshchin MV, Smirnova MP, Kelmanson I, Belousov VV, Balaban PM, Zaitsev AV. Overexpression of KCNN4 channels in principal neurons produces an anti-seizure effect without reducing their coding ability. Gene Ther 2024; 31:144-153. [PMID: 37968509 DOI: 10.1038/s41434-023-00427-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/13/2023] [Accepted: 10/24/2023] [Indexed: 11/17/2023]
Abstract
Gene therapy offers a potential alternative to the surgical treatment of epilepsy, which affects millions of people and is pharmacoresistant in ~30% of cases. Aimed at reducing the excitability of principal neurons, the engineered expression of K+ channels has been proposed as a treatment due to the outstanding ability of K+ channels to hyperpolarize neurons. However, the effects of K+ channel overexpression on cell physiology remain to be investigated. Here we report an adeno-associated virus (AAV) vector designed to reduce epileptiform activity specifically in excitatory pyramidal neurons by expressing the human Ca2+-gated K+ channel KCNN4 (KCa3.1). Electrophysiological and pharmacological experiments in acute brain slices showed that KCNN4-transduced cells exhibited a Ca2+-dependent slow afterhyperpolarization that significantly decreased the ability of KCNN4-positive neurons to generate high-frequency spike trains without affecting their lower-frequency coding ability and action potential shapes. Antiepileptic activity tests showed potent suppression of pharmacologically induced seizures in vitro at both single cell and local field potential levels with decreased spiking during ictal discharges. Taken together, our findings strongly suggest that the AAV-based expression of the KCNN4 channel in excitatory neurons is a promising therapeutic intervention as gene therapy for epilepsy.
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Affiliation(s)
- Evgeny S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, RAS, 117485, Moscow, Russia.
| | - Tatiana Y Postnikova
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 194223, Saint Petersburg, Russia
| | - Elena Y Proskurina
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 194223, Saint Petersburg, Russia
| | | | - Violetta Ivanova
- Institute of Higher Nervous Activity and Neurophysiology, RAS, 117485, Moscow, Russia
| | - Matvey V Roshchin
- Institute of Higher Nervous Activity and Neurophysiology, RAS, 117485, Moscow, Russia
| | - Maria P Smirnova
- Institute of Higher Nervous Activity and Neurophysiology, RAS, 117485, Moscow, Russia
| | - Ilya Kelmanson
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997, Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997, Moscow, Russia
| | - Vsevolod V Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997, Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997, Moscow, Russia
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, 117997, Moscow, Russia
- Life Improvement by Future Technologies (LIFT) Center, 143025, Moscow, Russia
| | - Pavel M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, RAS, 117485, Moscow, Russia
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, 194223, Saint Petersburg, Russia.
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2
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Ho AMC, Peyton MP, Scaletty SJ, Trapp S, Schreiber A, Madden BJ, Choi DS, Matthews DB. Chronic Intermittent Ethanol Exposure Alters Behavioral Flexibility in Aged Rats Compared to Adult Rats and Modifies Protein and Protein Pathways Related to Alzheimer's Disease. ACS OMEGA 2022; 7:46260-46276. [PMID: 36570296 PMCID: PMC9774340 DOI: 10.1021/acsomega.2c04528] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/17/2022] [Indexed: 05/13/2023]
Abstract
Repeated excessive alcohol consumption increases the risk of developing cognitive decline and dementia. Hazardous drinking among older adults further increases such vulnerabilities. To investigate whether alcohol induces cognitive deficits in older adults, we performed a chronic intermittent ethanol exposure paradigm (ethanol or water gavage every other day 10 times) in 8-week-old young adult and 70-week-old aged rats. While spatial memory retrieval ascertained by probe trials in the Morris water maze was not significantly different between ethanol-treated and water-treated rats in both age groups after the fifth and tenth gavages, behavioral flexibility was impaired in ethanol-treated rats compared to water-treated rats in the aged group but not in the young adult group. We then examined ethanol-treatment-associated hippocampal proteomic and phosphoproteomic differences distinct in the aged rats. We identified several ethanol-treatment-related proteins, including the upregulations of the Prkcd protein level, several of its phosphosites, and its kinase activity and downregulation in the Camk2a protein level. Our bioinformatic analysis revealed notable changes in pathways involved in neurotransmission regulation, synaptic plasticity, neuronal apoptosis, and insulin receptor signaling. In conclusion, our behavioral and proteomic results identified several candidate proteins and pathways potentially associated with alcohol-induced cognitive decline in aged adults.
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Affiliation(s)
- Ada Man-Choi Ho
- Department
of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Mina P. Peyton
- Bioinformatics
and Computational Biology Program, University
of Minnesota, Minneapolis, Minnesota55455, United States
| | - Samantha J. Scaletty
- Department
of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Sarah Trapp
- Department
of Psychology, University of Wisconsin—Eau
Claire, Eau Claire, Wisconsin54701, United States
| | - Areonna Schreiber
- Department
of Psychology, University of Wisconsin—Eau
Claire, Eau Claire, Wisconsin54701, United States
| | - Benjamin J. Madden
- Mayo
Clinic Proteomics Core, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Doo-Sup Choi
- Department
of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota55905, United States
- Department
of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota55905, United States
| | - Douglas B. Matthews
- Department
of Psychology, University of Wisconsin—Eau
Claire, Eau Claire, Wisconsin54701, United States
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3
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Śliwińska MA, Cały A, Borczyk M, Ziółkowska M, Skonieczna E, Chilimoniuk M, Bernaś T, Giese KP, Radwanska K. Long-term Memory Upscales Volume of Postsynaptic Densities in the Process that Requires Autophosphorylation of αCaMKII. Cereb Cortex 2021; 30:2573-2585. [PMID: 31800021 DOI: 10.1093/cercor/bhz261] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
It is generally accepted that formation and storage of memory relies on alterations of the structure and function of brain circuits. However, the structural data, which show learning-induced and long-lasting remodeling of synapses, are still very sparse. Here, we reconstruct 1927 dendritic spines and their postsynaptic densities (PSDs), representing a postsynaptic part of the glutamatergic synapse, in the hippocampal area CA1 of the mice that underwent spatial training. We observe that in young adult (5 months), mice volume of PSDs, but not the volume of the spines, is increased 26 h after the training. The training-induced growth of PSDs is specific for the dendritic spines that lack smooth endoplasmic reticulum and spine apparatuses, and requires autophosphorylation of αCaMKII. Interestingly, aging alters training-induced ultrastructural remodeling of dendritic spines. In old mice, both the median volumes of dendritic spines and PSDs shift after training toward bigger values. Overall, our data support the hypothesis that formation of memory leaves long-lasting footprint on the ultrastructure of brain circuits; however, the form of circuit remodeling changes with age.
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Affiliation(s)
- Małgorzata Alicja Śliwińska
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland.,Laboratory of Imaging Tissue Structure and Function, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Anna Cały
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Malgorzata Borczyk
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Magdalena Ziółkowska
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Edyta Skonieczna
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Magdalena Chilimoniuk
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
| | - Tytus Bernaś
- Laboratory of Imaging Tissue Structure and Function, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland.,Department of Anatomy and Neurology, VCU School of Medicine, Richmond, VA 23298, USA
| | - K Peter Giese
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 9NU, UK
| | - Kasia Radwanska
- Laboratory of Molecular Basis of Behavior, The Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw 02-093, Poland
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4
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Kim KR, Jeong HJ, Kim Y, Lee SY, Kim Y, Kim HJ, Lee SH, Cho H, Kang JS, Ho WK. Calbindin regulates Kv4.1 trafficking and excitability in dentate granule cells via CaMKII-dependent phosphorylation. Exp Mol Med 2021; 53:1134-1147. [PMID: 34234278 PMCID: PMC8333054 DOI: 10.1038/s12276-021-00645-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 02/06/2023] Open
Abstract
Calbindin, a major Ca2+ buffer in dentate granule cells (GCs), plays a critical role in shaping Ca2+ signals, yet how it regulates neuronal function remains largely unknown. Here, we found that calbindin knockout (CBKO) mice exhibited dentate GC hyperexcitability and impaired pattern separation, which co-occurred with reduced K+ current due to downregulated surface expression of Kv4.1. Relatedly, manipulation of calbindin expression in HT22 cells led to changes in CaMKII activation and the level of surface localization of Kv4.1 through phosphorylation at serine 555, confirming the mechanism underlying neuronal hyperexcitability in CBKO mice. We also discovered that Ca2+ buffering capacity was significantly reduced in the GCs of Tg2576 mice to the level of CBKO GCs, and this reduction was restored to normal levels by antioxidants, suggesting that calbindin is a target of oxidative stress. Our data suggest that the regulation of CaMKII signaling by Ca2+ buffering is crucial for neuronal excitability regulation.
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Affiliation(s)
- Kyung-Ran Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Institute of BioInnovation Research, Kolon Life Science Inc, 110 Magokdong-ro, Gangseo-gu, Seoul, 07793, Korea
| | - Hyeon-Ju Jeong
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Yoonsub Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
| | - Seung Yeon Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
| | - Yujin Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea
| | - Hyun-Ji Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Suk-Ho Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Hana Cho
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Jong-Sun Kang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea.
| | - Won-Kyung Ho
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea.
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea.
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5
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Chen L, Cummings KA, Mau W, Zaki Y, Dong Z, Rabinowitz S, Clem RL, Shuman T, Cai DJ. The role of intrinsic excitability in the evolution of memory: Significance in memory allocation, consolidation, and updating. Neurobiol Learn Mem 2020; 173:107266. [PMID: 32512183 PMCID: PMC7429265 DOI: 10.1016/j.nlm.2020.107266] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 05/28/2020] [Accepted: 05/31/2020] [Indexed: 11/30/2022]
Abstract
Memory is a dynamic process that is continuously regulated by both synaptic and intrinsic neural mechanisms. While numerous studies have shown that synaptic plasticity is important in various types and phases of learning and memory, neuronal intrinsic excitability has received relatively less attention, especially regarding the dynamic nature of memory. In this review, we present evidence demonstrating the importance of intrinsic excitability in memory allocation, consolidation, and updating. We also consider the intricate interaction between intrinsic excitability and synaptic plasticity in shaping memory, supporting both memory stability and flexibility.
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Affiliation(s)
- Lingxuan Chen
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Kirstie A Cummings
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - William Mau
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Yosif Zaki
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Zhe Dong
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Sima Rabinowitz
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Roger L Clem
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Tristan Shuman
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Denise J Cai
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States.
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6
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Wang J, Yang C, Wang H, Li D, Li T, Sun Y, Zhao M, Ma J, Hua W, Yang Z. A New Rat Model of Chronic Cerebral Hypoperfusion Resulting in Early-Stage Vascular Cognitive Impairment. Front Aging Neurosci 2020; 12:86. [PMID: 32351379 PMCID: PMC7174718 DOI: 10.3389/fnagi.2020.00086] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/12/2020] [Indexed: 12/12/2022] Open
Abstract
Objective Currently, most models of vascular cognitive impairment are established by occluding the carotid arteries uni- or bilaterally to reduce the cerebral blood flow mimicking chronic cerebral hypoxia. Due to the sudden blood flow interruption, a gradual narrowing of the carotid artery cannot be completely imitated. This paper aims to establish a bilateral carotid stenosis model with mild cognitive dysfunction and mild white matter changes to simulate patients with vascular predementia. Methods Aged Wistar rats (18 months old) underwent either bilateral common carotid artery stenosis (BCAS) or occlusion (BCAO) surgery or a sham operation (control group). The cerebral blood flow in the frontal cortex was measured using Doppler flowmetry. Thirty days after surgery, cognitive function impairments were determined with the Morris water maze; cerebral magnetic resonance imaging was performed to detect changes in fractional anisotropy to assess white matter injuries, and histological studies were performed. Results The aged rats in the BCAS group showed a more gradual cerebral blood flow reduction and a lower mortality rate (11%) compared to rats in the BCAO group. The water maze test revealed a more marginal impairment affecting spatial learning and memory in rats with BCAS than in rats with BCAO. Diffusion tensor imaging detected white matter injuries in the hippocampus and cerebral cortex of BCAS rats. Particularly, a small portion of nerve fibers of the lateral somatosensory cortex was significantly different between rats of the BCAO and BCAS groups. In the BCAS group, the microscopic structure of the hippocampal CA1 region changed slightly after 30 days and sustained a slight mitochondrial crista crack. Fluorescence staining indicated that the number of GFAP-positive cells was increased in rat brains of the BCAS group, and this phenomenon was even more pronounced in the BCAO group. The hnRNPA2/B1 and GABAAR-α1 expression levels were significantly decreased in the hippocampus of rats with BCAS compared to those of controls. Conclusion Severe bilateral carotid stenosis induced mild cognitive dysfunction and slight structural changes in the brains of aged rats. Thus, a chronic cerebral hypoperfusion model was successfully established.
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Affiliation(s)
- Jinxin Wang
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Chenyi Yang
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Haiyun Wang
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China.,Medical College of Nankai University, Nankai University, Tianjin, China.,Tianjin Research Institute of Anesthesiology, Tianjin, China
| | - Dongxue Li
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Tang Li
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Yi Sun
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Mingshu Zhao
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Ji Ma
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Wei Hua
- Department of Anesthesiology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Nankai University Affinity the Third Central Hospital, Tianjin Institute of Hepatobiliary Disease, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin, China
| | - Zhuo Yang
- Medical College of Nankai University, Nankai University, Tianjin, China
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7
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Oh MM, Disterhoft JF. Learning and aging affect neuronal excitability and learning. Neurobiol Learn Mem 2019; 167:107133. [PMID: 31786311 DOI: 10.1016/j.nlm.2019.107133] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/21/2019] [Accepted: 11/27/2019] [Indexed: 11/20/2022]
Abstract
The first study that demonstrated a change in intrinsic neuronal excitability after learning in ex vivo brain tissue slices from a mammal was published over thirty years ago. Numerous other manuscripts describing similar learning-related changes have followed over the years since the original paper demonstrating the postburst afterhyperpolarization (AHP) reduction in CA1 pyramidal neurons from rabbits that learned delay eyeblink conditioning was published. In addition to the learning-related changes, aging-related enlargement of the postburst AHP in CA1 pyramidal neurons have been reported. Extensive work has been done relating slow afterhyperpolarization enhancement in CA1 hippocampus to slowed learning in some aging animals. These reproducible findings strongly implicate modulation of the postburst AHP as an essential cellular mechanism necessary for successful learning, at least in learning tasks that engage CA1 hippocampal pyramidal neurons.
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Affiliation(s)
- M Matthew Oh
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, United States
| | - John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, United States.
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8
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Venkat P, Chopp M, Zacharek A, Cui C, Landschoot-Ward J, Qian Y, Chen Z, Chen J. Sildenafil treatment of vascular dementia in aged rats. Neurochem Int 2019; 127:103-112. [DOI: 10.1016/j.neuint.2018.12.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/24/2018] [Accepted: 12/24/2018] [Indexed: 01/08/2023]
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9
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Djurisic M, Brott BK, Saw NL, Shamloo M, Shatz CJ. Activity-dependent modulation of hippocampal synaptic plasticity via PirB and endocannabinoids. Mol Psychiatry 2019; 24:1206-1219. [PMID: 29670176 PMCID: PMC6372352 DOI: 10.1038/s41380-018-0034-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 01/21/2018] [Accepted: 01/31/2018] [Indexed: 12/18/2022]
Abstract
The threshold for Hebbian synaptic plasticity in the CNS is modulated by prior synaptic activity. At adult CA3-CA1 synapses, endocannabinoids play a role in this process, but how activity engages and maintains this retrograde signaling system is not well understood. Here we show that conditional deletion of Paired Immunoglobulin-like receptor B (PirB) from pyramidal neurons in adult mouse hippocampus results in deficient LTD at CA3-CA1 synapses over a range of stimulation frequencies, accompanied by an increase in LTP. This finding can be fully explained by the disengagement of retrograde endocannabinoid signaling selectively at excitatory synapses. In the absence of PirB, the NMDAR-dependent regulation of endocannabinoid signaling is lost, while CB1R-dependent and group I mGluR-dependent regulation are intact. Moreover, mEPSC frequency in mutant CA1 pyramidal cells is elevated, consistent with a higher density of excitatory synapses and altered synapse pruning. Mice lacking PirB also perform better than WT in learning and memory tasks. These observations suggest that PirB is an integral part of an NMDA receptor-mediated synaptic mechanism that maintains bidirectional Hebbian plasticity and learning via activity-dependent endocannabinoid signaling.
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Affiliation(s)
- Maja Djurisic
- Departments of Biology and Neurobiology, and Bio-X, Stanford University, Stanford, CA, 94305, USA.
| | - Barbara K. Brott
- 0000000419368956grid.168010.eDepartments of Biology and Neurobiology, and Bio-X, Stanford University, Stanford, CA 94305 USA
| | - Nay L. Saw
- 0000000419368956grid.168010.eBehavioral and Functional Neuroscience Laboratory, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Mehrdad Shamloo
- 0000000419368956grid.168010.eBehavioral and Functional Neuroscience Laboratory, Stanford University School of Medicine, Stanford, CA 94305 USA ,0000000419368956grid.168010.eBehavioral and Functional Neuroscience Laboratory and Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Carla J. Shatz
- 0000000419368956grid.168010.eDepartments of Biology and Neurobiology, and Bio-X, Stanford University, Stanford, CA 94305 USA
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10
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Takashima Y, Tseng J, Fannon MJ, Purohit DC, Quach LW, Terranova MJ, Kharidia KM, Oliver RJ, Mandyam CD. Sex Differences in Context-Driven Reinstatement of Methamphetamine Seeking is Associated with Distinct Neuroadaptations in the Dentate Gyrus. Brain Sci 2018; 8:brainsci8120208. [PMID: 30487415 PMCID: PMC6316047 DOI: 10.3390/brainsci8120208] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/16/2018] [Accepted: 11/22/2018] [Indexed: 12/15/2022] Open
Abstract
The present study examined differences in operant responses in adult male and female rats during distinct phases of addiction. Males and females demonstrated escalation in methamphetamine (0.05 mg/kg, i.v.) intake with females showing enhanced latency to escalate, and bingeing. Following protracted abstinence, females show reduced responses during extinction, and have greater latency to extinguish compared with males, indicating reduced craving. Females demonstrated lower context-driven reinstatement compared to males, indicating that females have less motivational significance to the context associated with methamphetamine. Whole-cell patch-clamp recordings on dentate gyrus (DG) granule cell neurons (GCNs) were performed in acute brain slices from controls and methamphetamine experienced male and female rats, and neuronal excitability was evaluated from GCNs. Reinstatement of methamphetamine seeking reduced spiking in males, and increased spiking in females compared to controls, demonstrating distinct neuroadaptations in intrinsic excitability of GCNs in males and females. Reduced excitability of GCNs in males was associated with enhanced levels of neural progenitor cells, expression of plasticity-related proteins including CaMKII, and choline acetyltransferase in the DG. Enhanced excitability in females was associated with an increased GluN2A/2B ratio, indicating changes in postsynaptic GluN subunit composition in the DG. Altered intrinsic excitability of GCNs was associated with reduced mossy fiber terminals in the hilus and pyramidal projections, demonstrating compromised neuroplasticity in the DG in both sexes. The alterations in excitability, plasticity-related proteins, and mossy fiber density were correlated with enhanced activation of microglial cells in the hilus, indicating neuroimmune responses in both sexes. Together, the present results indicate sexually dimorphic adaptive biochemical changes in excitatory neurotransmitter systems in the DG and highlight the importance of including sex as a biological variable in exploring neuroplasticity and neuroimmune changes that predict enhanced relapse to methamphetamine-seeking behaviors.
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Affiliation(s)
- Yoshio Takashima
- Department of Anesthesiology, University of California San Diego, San Diego, CA 92161, USA.
- VA San Diego Healthcare System, San Diego, CA 92161, USA.
| | - Joyee Tseng
- VA San Diego Healthcare System, San Diego, CA 92161, USA.
| | | | | | - Leon W Quach
- VA San Diego Healthcare System, San Diego, CA 92161, USA.
| | | | | | | | - Chitra D Mandyam
- Department of Anesthesiology, University of California San Diego, San Diego, CA 92161, USA.
- VA San Diego Healthcare System, San Diego, CA 92161, USA.
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11
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Harda Z, Dzik JM, Nalberczak-Skóra M, Meyza K, Łukasiewicz K, Łęski S, Radwanska K. Autophosphorylation of αCaMKII affects social interactions in mice. GENES BRAIN AND BEHAVIOR 2018; 17:e12457. [DOI: 10.1111/gbb.12457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/22/2017] [Accepted: 01/05/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Z. Harda
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - J. M. Dzik
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - M. Nalberczak-Skóra
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - K. Meyza
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - K. Łukasiewicz
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - S. Łęski
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - K. Radwanska
- The Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
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12
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Meadows JP, Guzman-Karlsson MC, Phillips S, Brown JA, Strange SK, Sweatt JD, Hablitz JJ. Dynamic DNA methylation regulates neuronal intrinsic membrane excitability. Sci Signal 2016; 9:ra83. [PMID: 27555660 DOI: 10.1126/scisignal.aaf5642] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epigenetic modifications, such as DNA cytosine methylation, contribute to the mechanisms underlying learning and memory by coordinating adaptive gene expression and neuronal plasticity. Transcription-dependent plasticity regulated by DNA methylation includes synaptic plasticity and homeostatic synaptic scaling. Memory-related plasticity also includes alterations in intrinsic membrane excitability mediated by changes in the abundance or activity of ion channels in the plasma membrane, which sets the threshold for action potential generation. We found that prolonged inhibition of DNA methyltransferase (DNMT) activity increased intrinsic membrane excitability of cultured cortical pyramidal neurons. Knockdown of the cytosine demethylase TET1 or inhibition of RNA polymerase blocked the increased membrane excitability caused by DNMT inhibition, suggesting that this effect was mediated by subsequent cytosine demethylation and de novo transcription. Prolonged DNMT inhibition blunted the medium component of the after-hyperpolarization potential, an effect that would increase neuronal excitability, and was associated with reduced expression of the genes encoding small-conductance Ca(2+)-activated K(+) (SK) channels. Furthermore, the specific SK channel blocker apamin increased neuronal excitability but was ineffective after DNMT inhibition. Our results suggested that DNMT inhibition enables transcriptional changes that culminate in decreased expression of SK channel-encoding genes and decreased activity of SK channels, thus providing a mechanism for the regulation of neuronal intrinsic membrane excitability by dynamic DNA cytosine methylation. This study has implications for human neurological and psychiatric diseases associated with dysregulated intrinsic excitability.
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Affiliation(s)
- Jarrod P Meadows
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mikael C Guzman-Karlsson
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Scott Phillips
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jordan A Brown
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Sarah K Strange
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - J David Sweatt
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA. Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John J Hablitz
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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13
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Abstract
Over the past decade, since epigenetic mechanisms were first implicated in memory formation and synaptic plasticity, dynamic DNA methylation reactions have been identified as integral to long-term memory formation, maintenance, and recall. This review incorporates various new findings that DNA methylation mechanisms are important regulators of non-Hebbian plasticity mechanisms, suggesting that these epigenetic mechanisms are a fundamental link between synaptic plasticity and metaplasticity. Because the field of neuroepigenetics is so young and the biochemical tools necessary to probe gene-specific questions are just now being developed and used, this review also speculates about the direction and potential of therapeutics that target epigenetic mechanisms in the central nervous system and the unique pharmacokinetic and pharmacodynamic properties that epigenetic therapies may possess. Mapping the dynamics of the epigenome in response to experiential learning, even a single epigenetic mark in isolation, remains a significant technical and bioinformatic hurdle facing the field, but will be necessary to identify changes to the methylome that govern memory-associated gene expression and effectively drug the epigenome.
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Affiliation(s)
- Andrew J Kennedy
- a Department of Neurobiology , University of Alabama at Birmingham , Birmingham , AL , USA
| | - J David Sweatt
- a Department of Neurobiology , University of Alabama at Birmingham , Birmingham , AL , USA
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14
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Wójtowicz T, Brzdąk P, Mozrzymas JW. Diverse impact of acute and long-term extracellular proteolytic activity on plasticity of neuronal excitability. Front Cell Neurosci 2015; 9:313. [PMID: 26321914 PMCID: PMC4530619 DOI: 10.3389/fncel.2015.00313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/28/2015] [Indexed: 12/13/2022] Open
Abstract
Learning and memory require alteration in number and strength of existing synaptic connections. Extracellular proteolysis within the synapses has been shown to play a pivotal role in synaptic plasticity by determining synapse structure, function, and number. Although synaptic plasticity of excitatory synapses is generally acknowledged to play a crucial role in formation of memory traces, some components of neural plasticity are reflected by nonsynaptic changes. Since information in neural networks is ultimately conveyed with action potentials, scaling of neuronal excitability could significantly enhance or dampen the outcome of dendritic integration, boost neuronal information storage capacity and ultimately learning. However, the underlying mechanism is poorly understood. With this regard, several lines of evidence and our most recent study support a view that activity of extracellular proteases might affect information processing in neuronal networks by affecting targets beyond synapses. Here, we review the most recent studies addressing the impact of extracellular proteolysis on plasticity of neuronal excitability and discuss how enzymatic activity may alter input-output/transfer function of neurons, supporting cognitive processes. Interestingly, extracellular proteolysis may alter intrinsic neuronal excitability and excitation/inhibition balance both rapidly (time of minutes to hours) and in long-term window. Moreover, it appears that by cleavage of extracellular matrix (ECM) constituents, proteases may modulate function of ion channels or alter inhibitory drive and hence facilitate active participation of dendrites and axon initial segments (AISs) in adjusting neuronal input/output function. Altogether, a picture emerges whereby both rapid and long-term extracellular proteolysis may influence some aspects of information processing in neurons, such as initiation of action potential, spike frequency adaptation, properties of action potential and dendritic backpropagation.
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Affiliation(s)
- Tomasz Wójtowicz
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University Wroclaw, Poland
| | - Patrycja Brzdąk
- Department of Animal Physiology, Institute of Experimental Biology, Wroclaw University Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University Wroclaw, Poland ; Department of Animal Physiology, Institute of Experimental Biology, Wroclaw University Wroclaw, Poland
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15
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Venkat P, Chopp M, Chen J. Models and mechanisms of vascular dementia. Exp Neurol 2015; 272:97-108. [PMID: 25987538 DOI: 10.1016/j.expneurol.2015.05.006] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 05/04/2015] [Accepted: 05/08/2015] [Indexed: 02/02/2023]
Abstract
Vascular dementia (VaD) is the second leading form of dementia after Alzheimer's disease (AD) plaguing the elderly population. VaD is a progressive disease caused by reduced blood flow to the brain, and it affects cognitive abilities especially executive functioning. VaD is poorly understood and lacks suitable animal models, which constrain the progress on understanding the basis of the disease and developing treatments. This review article discusses VaD, its risk factors, induced cognitive disability, various animal (rodent) models of VaD, pathology, and mechanisms of VaD and treatment options.
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Affiliation(s)
- Poornima Venkat
- Neurology, Henry Ford Hospital, Detroit, MI, USA; Physics, Oakland University, Rochester, MI, USA.
| | - Michael Chopp
- Neurology, Henry Ford Hospital, Detroit, MI, USA; Physics, Oakland University, Rochester, MI, USA.
| | - Jieli Chen
- Neurology, Henry Ford Hospital, Detroit, MI, USA; Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, Tianjin, China.
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16
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Guzman-Karlsson MC, Meadows JP, Gavin CF, Hablitz JJ, Sweatt JD. Transcriptional and epigenetic regulation of Hebbian and non-Hebbian plasticity. Neuropharmacology 2014; 80:3-17. [PMID: 24418102 DOI: 10.1016/j.neuropharm.2014.01.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/30/2013] [Accepted: 01/01/2014] [Indexed: 01/02/2023]
Abstract
The epigenome is uniquely positioned as a point of convergence, integrating multiple intracellular signaling cascades into a cohesive gene expression profile necessary for long-term behavioral change. The last decade of neuroepigenetic research has primarily focused on learning-induced changes in DNA methylation and chromatin modifications. Numerous studies have independently demonstrated the importance of epigenetic modifications in memory formation and retention as well as Hebbian plasticity. However, how these mechanisms operate in the context of other forms of plasticity is largely unknown. In this review, we examine evidence for epigenetic regulation of Hebbian plasticity. We then discuss how non-Hebbian forms of plasticity, such as intrinsic plasticity and synaptic scaling, may also be involved in producing the cellular adaptations necessary for learning-related behavioral change. Furthermore, we consider the likely roles for transcriptional and epigenetic mechanisms in the regulation of these plasticities. In doing so, we aim to expand upon the idea that epigenetic mechanisms are critical regulators of both Hebbian and non-Hebbian forms of plasticity that ultimately drive learning and memory.
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Affiliation(s)
| | - Jarrod P Meadows
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Cristin F Gavin
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John J Hablitz
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - J David Sweatt
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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17
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Ganesh A, Bogdanowicz W, Balamurugan K, Ragu Varman D, Rajan KE. Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx. Brain Res 2012; 1471:33-45. [PMID: 22796292 DOI: 10.1016/j.brainres.2012.06.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 06/08/2012] [Accepted: 06/25/2012] [Indexed: 11/26/2022]
Abstract
Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We examined two important examples of these, calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95, in regard to the functional role of early growth response gene-1 (egr-1) in regulation of olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx (family Pteropodidae). To test whether activation of egr-1 in the olfactory bulb (OB) is required for olfactory memory of these bats, bilaterally canulated individuals were infused with antisense (AS) or non-sense (NS)-oligodeoxynucleotides (ODN) of egr-1, or with phosphate buffer saline (PBS), 2h before the olfactory training. Our results showed that behavioral training significantly up-regulates immediate early gene (IEG) EGR-1 and key synaptic proteins Synaptotagmin-1(SYT-1), CaMKII and PSD-95, and phosphorylation of CaMKII in the OB at the protein level per se. Subsequently, we observed that egr-1 antisense-ODN infusion in the OB impaired olfactory memory and down regulates the expression of CaMKII and PSD-95, and the phosphorylation of CaMKII but not SYT-1. In contrast, NS-ODN or PBS had no effect on the expression of the PSDs CaMKII or PSD-95, or on the phosphorylation of CaMKII. When the egr-1 NS-ODN was infused in the OB after training for the novel odor there was no effect on olfactory memory. These findings suggest that egr-1 control the activation of CaMKII and PSD-95 during the process of olfactory memory formation.
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Affiliation(s)
- Ambigapathy Ganesh
- Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, India
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18
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Mohajeri MH, Giese KP. Two selected models of missense mutations in mice for the study of learning behaviour. Brain Res Bull 2011; 88:429-33. [PMID: 22214603 DOI: 10.1016/j.brainresbull.2011.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 12/01/2011] [Accepted: 12/17/2011] [Indexed: 01/19/2023]
Abstract
A large number of genome-wide association studies have linked missense mutations, mutations altering the amino acid sequence of proteins, with cognitive impairment in humans. However, these studies are correlative. As there may be multiple mutations for one particular patient, it is essential to address the functional impact of a missense mutation in a model system. The most suitable model system is the generation of knock-in mice with the homologous missense mutation followed by behavioural phenotyping. Here, we review selected mutants demonstrating an impact of single mutations on learning and memory in mice and discuss the relevance of such studies for understanding the role of these polymorphisms in human behaviour. We conclude that using these animal models has been instrumental in decoding the mechanisms underlying behaviour, and assists the design of therapeutic strategies for humans.
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Affiliation(s)
- M Hasan Mohajeri
- DSM Nutritional Products Ltd., R&D Human Nutrition and Health, Basel, Switzerland.
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19
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Kaczorowski CC. Bidirectional pattern-specific plasticity of the slow afterhyperpolarization in rats: role for high-voltage activated Ca2+ channels and I h. Eur J Neurosci 2011; 34:1756-65. [PMID: 22098477 DOI: 10.1111/j.1460-9568.2011.07899.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A burst of action potentials in hippocampal neurons is followed by a slow afterhyperpolarization (sAHP) that serves to limit subsequent firing. A reduction in the sAHP accompanies acquisition of several types of learning, whereas increases in the sAHP are correlated with cognitive impairment. The present study demonstrates in vitro that activity-dependent bidirectional plasticity of the sAHP does not require synaptic activation, and depends on the pattern of action potential firing. Whole-cell current-clamp recordings from CA1 pyramidal neurons in hippocampal slices from young rats (postnatal days 14-24) were performed in blockers of synaptic transmission. The sAHP was evoked by action potential firing at gamma-related (50 Hz, gamma-AHP) or theta frequencies (5 Hz, theta-AHP), two firing frequencies implicated in attention and memory. Interestingly, when the gamma-AHP and theta-AHP were evoked in the same cell, a gradual potentiation of the gamma-AHP (186 ± 31%) was observed that was blocked using Ca(2+) channel blockers nimodipine (10 μm) or ω-conotoxin MVIIC (1 μm). In experiments that exclusively evoked the sAHP with 50 Hz firing, the gamma-AHP was similarly potentiated (198 ± 44%). However, theta-burst firing pattern alone resulted in a decrease (65 ± 19%) of the sAHP. In these experiments, application of the h-channel blocker ZD7288 (25 μm) selectively prevented enhancement of the gamma-AHP. These data demonstrate that induction requirements for bidirectional AHP plasticity depend on the pattern of action potential firing, and result from distinct mechanisms. The identification of novel mechanisms underlying AHP plasticity in vitro provides additional insight into the dynamic processes that may regulate neuronal excitability during learning in vivo.
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Affiliation(s)
- C C Kaczorowski
- Department of Physiology and Institute for Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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20
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Mechanism for long-term memory formation when synaptic strengthening is impaired. Proc Natl Acad Sci U S A 2011; 108:18471-5. [PMID: 22025701 DOI: 10.1073/pnas.1109680108] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Long-term memory (LTM) formation has been linked with functional strengthening of existing synapses and other processes including de novo synaptogenesis. However, it is unclear whether synaptogenesis can contribute to LTM formation. Here, using α-calcium/calmodulin kinase II autophosphorylation-deficient (T286A) mutants, we demonstrate that when functional strengthening is severely impaired, contextual LTM formation is linked with training-induced PSD95 up-regulation followed by persistent generation of multiinnervated spines, a type of synapse that is characterized by several presynaptic terminals contacting the same postsynaptic spine. Both PSD95 up-regulation and contextual LTM formation in T286A mutants required signaling by the mammalian target of rapamycin (mTOR). Furthermore, we show that contextual LTM resists destabilization in T286A mutants, indicating that LTM is less flexible when synaptic strengthening is impaired. Taken together, we suggest that activation of mTOR signaling, followed by overexpression of PSD95 protein and synaptogenesis, contributes to formation of invariant LTM when functional strengthening is impaired.
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21
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Gamelli AE, McKinney BC, White JA, Murphy GG. Deletion of the L-type calcium channel Ca(V) 1.3 but not Ca(V) 1.2 results in a diminished sAHP in mouse CA1 pyramidal neurons. Hippocampus 2011; 21:133-41. [PMID: 20014384 DOI: 10.1002/hipo.20728] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Trains of action potentials in CA1 pyramidal neurons are followed by a prolonged calcium-dependent postburst afterhyperpolarization (AHP) that serves to limit further firing to a sustained depolarizing input. A reduction in the AHP accompanies acquisition of several types of learning and increases in the AHP are correlated with age-related cognitive impairment. The AHP develops primarily as the result of activation of outward calcium-activated potassium currents; however, the precise source of calcium for activation of the AHP remains unclear. There is substantial experimental evidence suggesting that calcium influx via voltage-gated L-type calcium channels (L-VGCCs) contributes to the generation of the AHP. Two L-VGCC subtypes are predominately expressed in the hippocampus, Ca(V) 1.2 and Ca(V) 1.3; however, it is not known which L-VGCC subtype is involved in generation of the AHP. This ambiguity is due in large part to the fact that at present there are no subunit-specific agonists or antagonists. Therefore, using mice in which the gene encoding Ca(V) 1.2 or Ca(V) 1.3 was deleted, we sought to determine the impact of alterations in levels of these two L-VCGG subtypes on neuronal excitability. No differences in any AHP measure were seen between neurons from Ca(V) 1.2 knockout mice and controls. However, the total area of the AHP was significantly smaller in neurons from Ca(V) 1.3 knockout mice as compared with neurons from wild-type controls. A significant reduction in the amplitude of the AHP was also seen at the 1 s time point in neurons from Ca(V) 1.3 knockout mice as compared with those from controls. Reductions in both the area and 1 s amplitude suggest the involvement of calcium influx via Ca(V) 1.3 in the slow AHP (sAHP). Thus, the results of our study demonstrate that deletion of Ca(V) 1.3, but not Ca(V) 1.2, significantly impacts the generation of the sAHP.
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Affiliation(s)
- Amy E Gamelli
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, Michigan, USA
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22
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Mechanisms underlying basal and learning-related intrinsic excitability in a mouse model of Alzheimer's disease. Neurobiol Aging 2009; 32:1452-65. [PMID: 19833411 DOI: 10.1016/j.neurobiolaging.2009.09.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/17/2009] [Accepted: 09/18/2009] [Indexed: 11/21/2022]
Abstract
Accumulations of β-amyloid (Aβ) contribute to neurological deficits associated with Alzheimer's disease (AD). The effects of Aβ on basal neuronal excitability and learning-related AHP plasticity were examined using whole-cell recordings from hippocampal neurons in the 5XFAD mouse model of AD. A robust increase in Aβ42 (and elevated levels of Aβ38-40) in naïve 5XFAD mice was associated with decreased basal neuronal excitability, evidenced by a select increase in Ca(2+)-sensitive afterhyperpolarization (AHP). Moreover, trace fear deficits observed in a subset of 5XFAD weak-learner mice were associated with a greater enhancement of the AHP in neurons, as compared to age-matched 5XFAD learner and 5XFAD naïve mice. Importantly, learning-related plasticity of the AHP remained intact in a subset of 5XFAD mice that learned trace fear conditioning to a set criterion. We show that APP-PS1 mutations enhance Aβ and disrupt basal excitability via a Ca(2+)-dependent enhancement of the AHP, and suggest disruption to learning-related modulation of intrinsic excitability resulted, in part, from altered cholinergic modulation of the AHP in the 5XFAD mouse model of AD (170 of 170).
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Abstract
The age of an experimental animal can be a critical variable, yet age matters are often overlooked within neuroscience. Many studies make use of young animals, without considering possible differences between immature and mature subjects. This is especially problematic when attempting to model traits or diseases that do not emerge until adulthood. In this commentary we discuss the reasons for this apparent bias in age of experimental animals, and illustrate the problem with a systematic review of published articles on long-term potentiation. Additionally, we review the developmental stages of a rat and discuss the difficulty of using the weight of an animal as a predictor of its age. Finally, we provide original data from our laboratory and review published data to emphasize that development is an ongoing process that does not end with puberty. Developmental changes can be quantitative in nature, involving gradual changes, rapid switches, or inverted U-shaped curves. Changes can also be qualitative. Thus, phenomena that appear to be unitary may be governed by different mechanisms at different ages. We conclude that selection of the age of the animals may be critically important in the design and interpretation of neurobiological studies.
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Affiliation(s)
- James Edgar McCutcheon
- Department of Cellular and Molecular Pharmacology, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA
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24
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Kaczorowski CC, Disterhoft JF. Memory deficits are associated with impaired ability to modulate neuronal excitability in middle-aged mice. Learn Mem 2009; 16:362-6. [PMID: 19470651 DOI: 10.1101/lm.1365609] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Normal aging disrupts hippocampal neuroplasticity and learning and memory. Aging deficits were exposed in a subset (30%) of middle-aged mice that performed below criterion on a hippocampal-dependent contextual fear conditioning task. Basal neuronal excitability was comparable in middle-aged and young mice, but learning-related modulation of the post-burst afterhyperpolarization (AHP)--a general mechanism engaged during learning--was impaired in CA1 neurons from middle-aged weak learners. Thus, modulation of neuronal excitability is critical for retention of context fear in middle-aged mice. Disruption of AHP plasticity may contribute to contextual fear deficits in middle-aged mice--a model of age-associated cognitive decline (AACD).
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Affiliation(s)
- Catherine C Kaczorowski
- Northwestern University Interdepartmental Neuroscience Program, Chicago, Illinois 60611, USA.
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25
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Sametsky EA, Disterhoft JF, Ohno M. Autophosphorylation of alphaCaMKII downregulates excitability of CA1 pyramidal neurons following synaptic stimulation. Neurobiol Learn Mem 2009; 92:120-3. [PMID: 19245842 DOI: 10.1016/j.nlm.2009.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/17/2009] [Accepted: 02/18/2009] [Indexed: 11/30/2022]
Abstract
It has been well documented that alpha-calcium/calmodulin-dependent protein kinase II (alphaCaMKII) is central to synaptic plasticity such as long-term potentiation, an activity-dependent strengthening of synapses that is thought to underlie certain types of learning and memory. However, the mechanisms by which alphaCaMKII may regulate neuronal excitability remain unclear. Here, we report that alphaCaMKII knock-in mice with a targeted T286A point mutation that prevents its autophosphorylation (alphaCaMKII(T286A)) showed increased excitability of CA1 pyramidal neurons compared with wild-type controls, as measured by a decrease in the slow component of post-burst afterhyperpolarization (sAHP) following high-frequency stimulation of Schaffer collateral afferent fibers. In contrast, AHP was indistinguishable between alphaCaMKII(T286A) and wild-type mice when it was evoked by somatic current injections, indicating that the hyperexcitability is observed specifically in response to synaptic stimulation in this mutant. Taken together, our results suggest that alphaCaMKII functions to downregulate CA1 neuron excitability following synaptic stimulation, presumably supporting the functionally adaptive modulation of excitability during hippocampal learning or providing a negative feedback mechanism that would prevent neurons from becoming hyperexcitable and promote network stability.
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Affiliation(s)
- Evgeny A Sametsky
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611-3008, USA
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26
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Liraz O, Rosenblum K, Barkai E. CAMKII activation is not required for maintenance of learning-induced enhancement of neuronal excitability. PLoS One 2009; 4:e4289. [PMID: 19172997 PMCID: PMC2627926 DOI: 10.1371/journal.pone.0004289] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 12/17/2008] [Indexed: 11/18/2022] Open
Abstract
Pyramidal neurons in the piriform cortex from olfactory-discrimination trained rats show enhanced intrinsic neuronal excitability that lasts for several days after learning. Such enhanced intrinsic excitability is mediated by long-term reduction in the post-burst after-hyperpolarization (AHP) which is generated by repetitive spike firing. AHP reduction is due to decreased conductance of a calcium-dependent potassium current, the sIAHP. We have previously shown that learning-induced AHP reduction is maintained by persistent protein kinase C (PKC) and extracellular regulated kinase (ERK) activation. However, the molecular machinery underlying this long-lasting modulation of intrinsic excitability is yet to be fully described. Here we examine whether the CaMKII, which is known to be crucial in learning, memory and synaptic plasticity processes, is instrumental for the maintenance of learning-induced AHP reduction. KN93, that selectively blocks CaMKII autophosphorylation at Thr286, reduced the AHP in neurons from trained and control rat to the same extent. Consequently, the differences in AHP amplitude and neuronal adaptation between neurons from trained rats and controls remained. Accordingly, the level of activated CaMKII was similar in pirifrom cortex samples taken form trained and control rats. Our data show that although CaMKII modulates the amplitude of AHP of pyramidal neurons in the piriform cortex, its activation is not required for maintaining learning-induced enhancement of neuronal excitability.
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Affiliation(s)
- Ori Liraz
- Department of Neurobiology, Faculty of Sciences, Haifa University, Haifa, Israel
- Department of Biology, Faculty of Sciences, Haifa University, Haifa, Israel
| | - Kobi Rosenblum
- Department of Neurobiology, Faculty of Sciences, Haifa University, Haifa, Israel
- Department of Biology, Faculty of Sciences, Haifa University, Haifa, Israel
| | - Edi Barkai
- Department of Neurobiology, Faculty of Sciences, Haifa University, Haifa, Israel
- Department of Biology, Faculty of Sciences, Haifa University, Haifa, Israel
- * E-mail:
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27
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Kimura R, Silva AJ, Ohno M. Autophosphorylation of alphaCaMKII is differentially involved in new learning and unlearning mechanisms of memory extinction. Learn Mem 2008; 15:837-43. [PMID: 18984565 DOI: 10.1101/lm.1049608] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Accumulating evidence indicates the key role of alpha-calcium/calmodulin-dependent protein kinase II (alphaCaMKII) in synaptic plasticity and learning, but it remains unclear how this kinase participates in the processing of memory extinction. Here, we investigated the mechanism by which alphaCaMKII may mediate extinction by using heterozygous knock-in mice with a targeted T286A mutation that prevents the autophosphorylation of this kinase (alphaCaMKII(T286A+/-)). Remarkably, partial reduction of alphaCaMKII function due to the T286A(+/-) mutation prevented the development of extinction without interfering with initial hippocampus-dependent memory formation as assessed by contextual fear conditioning and the Morris water maze. It is hypothesized that the mechanism of extinction may differ depending on the interval at which extinction training is started, being more akin to "new learning" at longer intervals and "unlearning" or "erasure" at shorter intervals. Consistent with this hypothesis, we found that extinction conducted 24 h, but not 15 min, after contextual fear training showed spontaneous recovery (reappearance of extinguished freezing responses) 21 d following the extinction, representing behavioral evidence for new learning and unlearning mechanisms underlying extinction 24 h and 15 min post-training, respectively. Importantly, the alphaCaMKII(T286A+/-) mutation blocked new learning of contextual fear memory extinction, whereas it did not interfere with unlearning processes. Our results demonstrate a genetic dissociation of new learning and unlearning mechanisms of extinction, and suggest that alphaCaMKII is responsible for extinguishing memories specifically through new learning mechanisms.
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Affiliation(s)
- Ryoichi Kimura
- Center for Dementia Research, Nathan Kline Institute, New York University School of Medicine, Orangeburg, New York 10962, USA
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Young SR, Bianchi R, Wong RKS. Signaling mechanisms underlying group I mGluR-induced persistent AHP suppression in CA3 hippocampal neurons. J Neurophysiol 2008; 99:1105-18. [PMID: 18184892 DOI: 10.1152/jn.00435.2007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activation of group I metabotropic glutamate receptors (mGluRs) leads to a concerted modulation of spike afterpotentials in guinea pig hippocampal neurons including a suppression of both medium and slow afterhyperpolarizations (AHPs). Suppression of AHPs may be long-lasting, in that it persists after washout of the agonist. Here, we show that persistent AHP suppression differs from short-term, transient suppression in that distinct and additional signaling processes are required to render the suppression persistent. Persistent AHP suppression followed DHPG application for 30 min, but not DHPG application for 5 min. Persistent AHP suppression was temperature dependent, occurring at 30-31 degrees C, but not at 25-26 degrees C. Preincubation of slices in inhibitors of protein synthesis (cycloheximide or anisomycin) prevented the persistent suppression of AHPs by DHPG. Similarly, preincubation of slices in an inhibitor of p38 MAP kinase (SB 203580) prevented persistent AHP suppression. In contrast, a blocker of p42/44 MAP kinase activation (PD 98059) had no effect on persistent AHP suppression. Additionally, we show that the mGluR5 antagonist MPEP, but not the mGluR1 antagonist LY 367385, prevented DHPG-induced persistent AHP suppression. Thus persistent AHP suppression by DHPG in hippocampal neurons requires activation of mGluR5. In addition, activation of p38 MAP kinase signaling and protein synthesis are required to impart persistence to the DHPG-activated AHP suppression.
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Affiliation(s)
- Steven R Young
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY 11203, USA.
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Alvarez EO, Alvarez PA. Motivated exploratory behaviour in the rat: The role of hippocampus and the histaminergic neurotransmission. Behav Brain Res 2008; 186:118-25. [PMID: 17825439 DOI: 10.1016/j.bbr.2007.07.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 07/26/2007] [Accepted: 07/30/2007] [Indexed: 11/25/2022]
Abstract
Exploration is one of most basic adaptive behavioural responses, giving the animal an important evolutionary advantage to survive in a changing environment. Inspection of novel environments might be come with motivated exploratory behaviour. In spite that this type of exploration in the rat is known for many years, little attention has been given to the intrinsic mechanisms or the brain structures that are involved in. In the present work the hippocampus, the neurotransmitter histamine, and the geometrical features of novel objects were examined in a model of conflictive and non-conflictive exploration in the rat which evaluates incentive-motivated exploration. Young adult intact rats were tested in a neutral non-conflictive behavioural activity detector (OVM), with (eOVM) or without (sOVM) novel objects. Three different objects were used: a box, a toy duck, and a tower. Results show that animals decrease its general motor activity (horizontal, ambulatory and non-ambulatory activity) in favor to exploration of the objects. Motivated exploration was not the same for all three objects. Rats explored significantly more the Tower and the Box objects than the Duck item. Behavioral patterns of hippocampus-implanted rats showed decreased scores in motor activity but maintained the difference in the relation of "without/with objects" exploration. When hippocampus-implanted rats were tested in a conflictive exploration device (the elevated asymmetric plus-maze), exploration of the No Wall arm, considered the most fear-inducing environment, was significantly more explored by the animal when the tower object was positioned at its end than when it was absent. Microinjection into the ventral hippocampus of histamine abolished this motivated exploratory response. Pre-treatment with pyrilamine, and not with ranitidine, was effective to block the inhibitory effect of histamine on the object motivated exploration. Results confirm that the hippocampus is involved on incentive motivated exploration, and suggest that histamine is part of an analyzing neuronal circuit of novelty incentivating behavioural responses in rats.
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Affiliation(s)
- Edgardo O Alvarez
- Area de Farmacología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, IMBECU-CONICET, Mendoza, Argentina.
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Abstract
Normal aging subjects, including humans, have difficulty learning hippocampus-dependent tasks. For example, at least 50% of normal aging rabbits and rats fail to meet a learning criterion in trace eyeblink conditioning. Many factors may contribute to this age-related learning impairment. An important cause is the reduced intrinsic excitability observed in hippocampal pyramidal neurons from normal aging subjects, as reflected by an enlarged postburst afterhyperpolarization (AHP) and an increased spike-frequency adaptation (accommodation). In this review, we will focus on the alterations in the AHP and accommodation during learning and normal aging. We propose that age-related increases in the postburst AHP and accommodation in hippocampal pyramidal neurons play an integral role in the learning impairment observed in normal aging subjects.
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Affiliation(s)
- John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA.
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Disterhoft JF, Oh MM. Learning, aging and intrinsic neuronal plasticity. Trends Neurosci 2006; 29:587-99. [PMID: 16942805 DOI: 10.1016/j.tins.2006.08.005] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 06/14/2006] [Accepted: 08/17/2006] [Indexed: 11/28/2022]
Abstract
In vitro experiments indicate that intrinsic neuronal excitability, as evidenced by changes in the post-burst afterhyperpolarization (AHP) and spike-frequency accommodation, is altered during learning and normal aging in the brain. Here we review these studies, highlighting two consistent findings: (i) that AHP and accommodation are reduced in pyramidal neurons from animals that have learned a task; and (ii) that AHP and accommodation are enhanced in pyramidal neurons from aging subjects, a cellular change that might contribute to age-related learning impairments. Findings from in vivo single-neuron recording studies complement the in vitro data. From these consistently reproduced findings, we propose that the intrinsic AHP level might determine the degree of synaptic plasticity and learning. Furthermore, it seems that reductions in the AHP must occur before learning if young and aging subjects are to learn a task successfully.
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Affiliation(s)
- John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA.
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