1
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Shkryl VM. The spatio-temporal properties of calcium transients in hippocampal pyramidal neurons in vitro. Front Cell Neurosci 2022; 16:1054950. [PMID: 36589284 PMCID: PMC9795003 DOI: 10.3389/fncel.2022.1054950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/24/2022] [Indexed: 12/15/2022] Open
Abstract
The spatio-temporal properties of calcium signals were studied in cultured pyramidal neurons of the hippocampus using two-dimensional fluorescence microscopy and ratiometric dye Fura-2. Depolarization-induced Ca2+ transients revealed an asynchronous delayed increase in free Ca2+ concentration. We found that the level of free resting calcium in the cell nucleus is significantly lower compared to the soma, sub-membrane, and dendritic tree regions. Calcium release from the endoplasmic reticulum under the action of several stimuli (field stimulation, high K+ levels, and caffeine) occurs in all areas studied. Under depolarization, calcium signals developed faster in the dendrites than in other areas, while their amplitude was significantly lower since larger and slower responses inside the soma. The peak value of the calcium response to the application of 10 mM caffeine, ryanodine receptors (RyRs) agonist, does not differ in the sub-membrane zone, central region, and nucleus but significantly decreases in the dendrites. In the presence of caffeine, the delay of Ca2+ signals between various areas under depolarization significantly declined. Thirty percentage of the peak amplitude of Ca2+ transients at prolonged electric field stimulation corresponded to calcium release from the ER store by RyRs, while short-term stimulation did not depend on them. 20 μM dantrolene, RyRs inhibitor, significantly reduces Ca2+ transient under high K+ levels depolarization of the neuron. RyRs-mediated enhancement of the Ca2+ signal is more pronounced in the central part and nucleus compared to the sub-membrane or dendrites regions of the neuron. In summary, using the ratiometric imaging allowed us to obtain additional information about the involvement of RyRs in the intracellular dynamics of Ca2+ signals induced by depolarization or electrical stimulation train, with an underlying change in Ca2+ concentration in various regions of interest in hippocampal pyramidal neurons.
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2
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Abstract
Pannexin-1 (Panx1) channels contribute to neurological disorders, including stroke and epilepsy, where their function has been linked to N-methyl D-aspartate (NMDA) receptors (NMDARs). We discovered that Ca2+ entry via NMDARs recruits endoplasmic reticulum–resident STIM proteins to activate Panx1 by binding to a hydrophobic region localized to the Panx1 N terminus. Using loss-of-function approaches, combined with molecular replacement and use of a STIM/Panx1 function–blocking antibody, we demonstrate that disrupting the STIM/Panx1 interaction prevents Panx1 activation by NMDARs, but not by hypotonic stimuli. Thus, our findings serve as a basis for the design of modality-specific inhibitors against STIM-dependent Panx1 activation that will aid in understanding the multimodal functions of Panx1 and their contribution to physiology and pathology. Pannexin-1 (Panx1) is a large-pore ion and solute permeable channel highly expressed in the nervous system, where it subserves diverse processes, including neurite outgrowth, dendritic spine formation, and N-methyl D-aspartate (NMDA) receptor (NMDAR)-dependent plasticity. Moreover, Panx1 dysregulation contributes to neurological disorders, including neuropathic pain, epilepsy, and excitotoxicity. Despite progress in understanding physiological and pathological functions of Panx1, the mechanisms that regulate its activity, including its ion and solute permeability, remain poorly understood. In this study, we identify endoplasmic reticulum (ER)-resident stromal interaction molecules (STIM1/2), which are Ca2+ sensors that communicate events within the ER to plasma membrane channels, as binding and signaling partners of Panx1. We demonstrate that Panx1 is activated to its large-pore configuration in response to stimuli that recruit STIM1/2 and map the interaction interface to a hydrophobic region within the N terminus of Panx1. We further characterize a Panx1 N terminus–recognizing antibody as a function-blocking tool able to prevent large-pore Panx1 activation by STIM1/2. Using either the function-blocking antibody or re-expression of Panx1 deletion mutants in Panx1 knockout (KO) neurons, we show that STIM recruitment couples Ca2+ entry via NMDARs to Panx1 activation, thereby identifying a model of NMDAR-STIM-Panx1 signaling in neurons. Our study highlights a previously unrecognized and important role of the Panx1 N terminus in regulating channel activation and membrane localization. Considering past work demonstrating an intimate functional relation between NMDARs and Panx1, our study opens avenues for understanding activation modality and context-specific functions of Panx1, including functions linked to diverse STIM-regulated cellular responses.
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3
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Goto JI, Fujii S, Fujiwara H, Mikoshiba K, Yamazaki Y. Synaptic plasticity in hippocampal CA1 neurons of mice lacking inositol-1,4,5-trisphosphate receptor-binding protein released with IP 3 (IRBIT). Learn Mem 2022; 29:110-119. [PMID: 35351819 PMCID: PMC8973391 DOI: 10.1101/lm.053542.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/02/2022] [Indexed: 01/02/2023]
Abstract
In hippocampal CA1 neurons of wild-type mice, a short tetanus (15 or 20 pulses at 100 Hz) or a standard tetanus (100 pulses at 100 Hz) to a naive input pathway induces long-term potentiation (LTP) of the responses. Low-frequency stimulation (LFS; 1000 pulses at 1 Hz) 60 min after the standard tetanus reverses LTP (depotentiation [DP]), while LFS applied 60 min prior to the standard tetanus suppresses LTP induction (LTP suppression). We investigated LTP, DP, and LTP suppression of both field excitatory postsynaptic potentials and population spikes in CA1 neurons of mice lacking the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R)-binding protein released with IP3 (IRBIT). The mean magnitudes of LTP induced by short and standard tetanus were not different in mutant and wild-type mice. In contrast, DP and LTP suppression were attenuated in mutant mice, whereby the mean magnitude of responses after LFS or tetanus were significantly greater than in wild-type mice. These results suggest that, in hippocampal CA1 neurons, IRBIT is involved in DP and LTP suppression, but is not essential for LTP. The attenuation of DP and LTP suppression in mice lacking IRBIT indicates that this protein, released during or after priming stimulations, determines the direction of LTP expression after the delivery of subsequent stimulations.
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Affiliation(s)
- Jun-Ichi Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Hiroki Fujiwara
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Center for Brain Science, Riken, Wako, Saitama 351-0198, Japan
| | - Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
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4
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Collingridge GL, Abraham WC. Glutamate receptors and synaptic plasticity: The impact of Evans and Watkins. Neuropharmacology 2021; 206:108922. [PMID: 34919905 DOI: 10.1016/j.neuropharm.2021.108922] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/23/2021] [Accepted: 12/09/2021] [Indexed: 12/31/2022]
Abstract
On the occasion of the 40 year anniversary of the hugely impactful review by Richard (Dick) Evans and Jeff Watkins, we describe how their work has impacted the field of synaptic plasticity. We describe their influence in each of the major glutamate receptor subtypes: AMPARs, NMDARs, KARs and mGluRs. Particular emphasis is placed on how their work impacted our own studies in the hippocampus. For example, we describe how the tools and regulators that they identified for studying NMDARs (e.g., NMDA, D-AP5 and Mg2+) led to the understanding of the molecular basis of the induction of LTP. We also describe how other tools that they introduced (e.g., (1S,3R)-ACPD and MCPG) helped lead to the concept of metaplasticity.
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Affiliation(s)
- G L Collingridge
- Department of Psychology, Brain Health Research Centre and Brain Research New Zealand, University of Otago, New Zealand; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada; TANZ Centre for Research in Neurodegenerative Diseases, Department of Physiology, University of Toronto, Toronto, ON, Canada.
| | - W C Abraham
- Department of Psychology, Brain Health Research Centre and Brain Research New Zealand, University of Otago, New Zealand
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5
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Maneshi MM, Toth AB, Ishii T, Hori K, Tsujikawa S, Shum AK, Shrestha N, Yamashita M, Miller RJ, Radulovic J, Swanson GT, Prakriya M. Orai1 Channels Are Essential for Amplification of Glutamate-Evoked Ca 2+ Signals in Dendritic Spines to Regulate Working and Associative Memory. Cell Rep 2020; 33:108464. [PMID: 33264616 PMCID: PMC7832685 DOI: 10.1016/j.celrep.2020.108464] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/14/2020] [Accepted: 11/10/2020] [Indexed: 11/18/2022] Open
Abstract
Store-operated Orai1 calcium channels function as highly Ca2+-selective ion channels and are broadly expressed in many tissues including the central nervous system, but their contributions to cognitive processing are largely unknown. Here, we report that many measures of synaptic, cellular, and behavioral models of learning are markedly attenuated in mice lacking Orai1 in forebrain excitatory neurons. Results with focal glutamate uncaging in hippocampal neurons support an essential role of Orai1 channels in amplifying NMDA-receptor-induced dendritic Ca2+ transients that drive activity-dependent spine morphogenesis and long-term potentiation at Schaffer collateral-CA1 synapses. Consistent with these signaling roles, mice lacking Orai1 in pyramidal neurons (but not interneurons) exhibit striking deficits in working and associative memory tasks. These findings identify Orai1 channels as essential regulators of dendritic spine Ca2+ signaling, synaptic plasticity, and cognition.
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Affiliation(s)
- Mohammad Mehdi Maneshi
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Anna B Toth
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Toshiyuki Ishii
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kotaro Hori
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Shogo Tsujikawa
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Andrew K Shum
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Nisha Shrestha
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Richard J Miller
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jelena Radulovic
- Department of Psychiatry, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Geoffrey T Swanson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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6
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Sharma VK, Singh TG, Singh S. Cyclic Nucleotides Signaling and Phosphodiesterase Inhibition: Defying Alzheimer's Disease. Curr Drug Targets 2020; 21:1371-1384. [PMID: 32718286 DOI: 10.2174/1389450121666200727104728] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 12/16/2022]
Abstract
Defects in brain functions associated with aging and neurodegenerative diseases benefit insignificantly from existing options, suggesting that there is a lack of understanding of pathological mechanisms. Alzheimer's disease (AD) is such a nearly untreatable, allied to age neurological deterioration for which only the symptomatic cure is available and the agents able to mould progression of the disease, is still far away. The altered expression of phosphodiesterases (PDE) and deregulated cyclic nucleotide signaling in AD has provoked a new thought of targeting cyclic nucleotide signaling in AD. Targeting cyclic nucleotides as an intracellular messenger seems to be a viable approach for certain biological processes in the brain and controlling substantial. Whereas, the synthesis, execution, and/or degradation of cyclic nucleotides has been closely linked to cognitive deficits. In relation to cognition, the cyclic nucleotides (cAMP and cGMP) have an imperative execution in different phases of memory, including gene transcription, neurogenesis, neuronal circuitry, synaptic plasticity and neuronal survival, etc. AD is witnessed by impairments of these basic processes underlying cognition, suggesting a crucial role of cAMP/cGMP signaling in AD populations. Phosphodiesterase inhibitors are the exclusive set of enzymes to facilitate hydrolysis and degradation of cAMP and cGMP thereby, maintains their optimum levels initiating it as an interesting target to explore. The present work reviews a neuroprotective and substantial influence of PDE inhibition on physiological status, pathological progression and neurobiological markers of AD in consonance with the intensities of cAMP and cGMP.
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Affiliation(s)
- Vivek K Sharma
- Chitkara College of Pharmacy, Chitkara University, Punjab, India,Govt. College of Pharmacy, Rohru, District Shimla, Himachal Pradesh-171207, India
| | - Thakur G Singh
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Shareen Singh
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
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7
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Fujii S, Yamazaki Y, Goto JI, Fujiwara H, Mikoshiba K. Depotentiation depends on IP 3 receptor activation sustained by synaptic inputs after LTP induction. ACTA ACUST UNITED AC 2020; 27:52-66. [PMID: 31949037 PMCID: PMC6970427 DOI: 10.1101/lm.050344.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/29/2020] [Indexed: 12/14/2022]
Abstract
In CA1 neurons of guinea pig hippocampal slices, long-term potentiation (LTP) was induced in field excitatory postsynaptic potentials (EPSPs) or population spikes (PSs) by the delivery of high-frequency stimulation (HFS, 100 pulses at 100 Hz) to CA1 synapses, and was reversed by the delivery of a train of low-frequency stimulation (LFS, 1000 pulses at 2 Hz) at 30 min after HFS (depotentiation), and this effect was inhibited when test synaptic stimulation was halted for a 19-min period after HFS or for a 20-min period after LFS or applied over the same time period in the presence of an antagonist of N-methyl-D-aspartate receptors (NMDARs), group I metabotropic glutamate receptors (mGluRs), or inositol 1, 4, 5-trisphosphate receptors (IP3Rs). Depotentiation was also blocked by the application of a Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor or a calcineurin inhibitor applied in the presence of test synaptic input for a 10-min period after HFS or for a 20-min period after LFS. These results suggest that, in postsynaptic neurons, the coactivation of NMDARs and group I mGluRs due to sustained synaptic activity following LTP induction results in the activation of IP3Rs and CaMKII, which leads to the activation of calcineurin after LFS and depotentiation of CA1 synaptic responses.
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Affiliation(s)
- Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.,Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Jun-Ichi Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.,Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Hiroki Fujiwara
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
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8
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Kumar A. Calcium Signaling During Brain Aging and Its Influence on the Hippocampal Synaptic Plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:985-1012. [PMID: 31646542 DOI: 10.1007/978-3-030-12457-1_39] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Calcium (Ca2+) ions are highly versatile intracellular signaling molecules and are universal second messenger for regulating a variety of cellular and physiological functions including synaptic plasticity. Ca2+ homeostasis in the central nervous system endures subtle dysregulation with advancing age. Research has provided abundant evidence that brain aging is associated with altered neuronal Ca2+ regulation and synaptic plasticity mechanisms. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during aging. The current chapter takes a specific perspective, assessing various Ca2+ sources and the influence of aging on Ca2+ sources and synaptic plasticity in the hippocampus. Integrating the knowledge of the complexity of age-related alterations in neuronal Ca2+ signaling and synaptic plasticity mechanisms will positively shape the development of highly effective therapeutics to treat brain disorders including cognitive impairment associated with aging and neurodegenerative disease.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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9
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Cheng S, Rong Y, Ma M, Lin X, Liu X, Li C, Yang X, Chen S. Modulation on tetrodotoxin-resistant sodium current of loureirin B in rat dorsal root ganglion neurons via cyclic AMP-dependent protein kinase A. J Cell Biochem 2019; 121:1790-1800. [PMID: 31642099 DOI: 10.1002/jcb.29414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/08/2019] [Indexed: 12/23/2022]
Abstract
To search the modulation mechanism of loureirin B, a flavonoid is extracted from Dracaena cochinchinensis, on tetrodotoxin-resistant (TTX-R) sodium channel in dorsal root ganglion (DRG) neurons of rats. Experiments were carried out based on patch-clamp technique and molecular biological methods. We observed the time-dependent inhibition of loureirin B on TTX-R sodium currents in DRG neurons and found that neither occupancy theory nor rate theory could well explain the time-dependent inhibitory effect of loureirin B on TTX-R sodium currents. It suggested that a second messenger-mediated signaling pathway may be involved in the modulation mechanism. So the cyclin AMP (cAMP) level of the DRG neurons before and after incubation with loureirin B was tested by ELISA Kit. Results showed that loureirin B could increase the cAMP level and the increased cAMP was caused by the enhancement of adenylate cyclase (AC) induced by loureirin B. Immunolabelling experiments further confirmed that loureirin B can promote the production of PKA in DRG neurons. In the presence of the PKA inhibitor H-89, the inhibitory effect of loureirin B on TTX-R sodium currents was reversed. Forskolin, a tool in biochemistry to raise the levels of cAMP, also could reduce TTX-R sodium currents similar to that of loureirin B. These studies demonstrated that loureirin B can modulate the TTX-R sodium channel in DRG neurons via an AC/cAMP/PKA pathway involving the activation of AC and PKA, which also can be used to explain the other pharmacological effects of loureirin B.
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Affiliation(s)
- Song Cheng
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Yi Rong
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Minjie Ma
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Xianguang Lin
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Xiangming Liu
- Gong Qing Institute of Science and Technology, Jiujiang, Jiangxi, China
| | - Chenhong Li
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Xiaofei Yang
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Su Chen
- Key Laboratory of Cognitive Science of State Ethnic Affairs Commission, Wuhan, Hubei, China.,Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis & Treatment, Wuhan, Hubei, China.,College of Biomedical Engineering, South-Central University for Nationalities, Wuhan, Hubei, China
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10
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Quantitation and Simulation of Single Action Potential-Evoked Ca 2+ Signals in CA1 Pyramidal Neuron Presynaptic Terminals. eNeuro 2019; 6:ENEURO.0343-19.2019. [PMID: 31551250 PMCID: PMC6800293 DOI: 10.1523/eneuro.0343-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 01/07/2023] Open
Abstract
Presynaptic Ca2+ evokes exocytosis, endocytosis, and synaptic plasticity. However, Ca2+ flux and interactions at presynaptic molecular targets are difficult to quantify because fluorescence imaging has limited resolution. In rats of either sex, we measured single varicosity presynaptic Ca2+ using Ca2+ dyes as buffers, and constructed models of Ca2+ dispersal. Action potentials evoked Ca2+ transients with little variation when measured with low-affinity dye (peak amplitude 789 ± 39 nM, within 2 ms of stimulation; decay times, 119 ± 10 ms). Endogenous Ca2+ buffering capacity, action potential-evoked free [Ca2+]i, and total Ca2+ amounts entering terminals were determined using Ca2+ dyes as buffers. These data constrained Monte Carlo (MCell) simulations of Ca2+ entry, buffering, and removal. Simulations of experimentally-determined Ca2+ fluxes, buffered by simulated calbindin28K well fit data, and were consistent with clustered Ca2+ entry followed within 4 ms by diffusion throughout the varicosity. Repetitive stimulation caused free varicosity Ca2+ to sum. However, simulated in nanometer domains, its removal by pumps and buffering was negligible, while local diffusion dominated. Thus, Ca2+ within tens of nanometers of entry, did not accumulate. A model of synaptotagmin1 (syt1)-Ca2+ binding indicates that even with 10 µM free varicosity evoked Ca2+, syt1 must be within tens of nanometers of channels to ensure occupation of all its Ca2+-binding sites. Repetitive stimulation, evoking short-term synaptic enhancement, does not modify probabilities of Ca2+ fully occupying syt1’s C2 domains, suggesting that enhancement is not mediated by Ca2+-syt1 interactions. We conclude that at spatiotemporal scales of fusion machines, Ca2+ necessary for their activation is diffusion dominated.
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11
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Padamsey Z, Foster WJ, Emptage NJ. Intracellular Ca 2+ Release and Synaptic Plasticity: A Tale of Many Stores. Neuroscientist 2019; 25:208-226. [PMID: 30014771 DOI: 10.1177/1073858418785334] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ca2+ is an essential trigger for most forms of synaptic plasticity. Ca2+ signaling occurs not only by Ca2+ entry via plasma membrane channels but also via Ca2+ signals generated by intracellular organelles. These organelles, by dynamically regulating the spatial and temporal extent of Ca2+ elevations within neurons, play a pivotal role in determining the downstream consequences of neural signaling on synaptic function. Here, we review the role of three major intracellular stores: the endoplasmic reticulum, mitochondria, and acidic Ca2+ stores, such as lysosomes, in neuronal Ca2+ signaling and plasticity. We provide a comprehensive account of how Ca2+ release from these stores regulates short- and long-term plasticity at the pre- and postsynaptic terminals of central synapses.
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Affiliation(s)
- Zahid Padamsey
- 1 Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, 15 George Square, Edinburgh, UK
| | - William J Foster
- 2 Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, Oxfordshire, UK
| | - Nigel J Emptage
- 2 Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, Oxfordshire, UK
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12
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Bliss T, Collingridge GL. Persistent memories of long-term potentiation and the N-methyl-d-aspartate receptor. Brain Neurosci Adv 2019; 3:2398212819848213. [PMID: 32166182 PMCID: PMC7058229 DOI: 10.1177/2398212819848213] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Indexed: 11/17/2022] Open
Abstract
In this article, we describe our involvement in the early days of research into long-term potentiation. We start with a description of the early experiments conducted in Oslo and London where long-term potentiation was first characterised. We discuss the ways in which the molecular pharmacology of glutamate receptors control the induction and expression of long-term potentiation and its counterpart, long-term depression. We then go on to summarise the extraordinary advances in understanding the cellular mechanisms of synaptic plasticity that have taken place in the subsequent half century. Finally, the increasing evidence that impaired long-term potentiation is a core feature of many brain disorders (LToPathies) is addressed by way of a few selected examples.
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Affiliation(s)
- Tvp Bliss
- The Francis Crick Institute, London, UK.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - G L Collingridge
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Tanz Centre for Research in Neurodegenerative Diseases and Department of Physiology, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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13
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Gavello D, Calorio C, Franchino C, Cesano F, Carabelli V, Carbone E, Marcantoni A. Early Alterations of Hippocampal Neuronal Firing Induced by Abeta42. Cereb Cortex 2019; 28:433-446. [PMID: 27999123 DOI: 10.1093/cercor/bhw377] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Indexed: 12/11/2022] Open
Abstract
We studied the effect of Amyloid β 1-42 oligomers (Abeta42) on Ca2+ dependent excitability profile of hippocampal neurons. Abeta42 is one of the Amyloid beta peptides produced by the proteolytic processing of the amyloid precursor protein and participates in the initiating event triggering the progressive dismantling of synapses and neuronal circuits. Our experiments on cultured hippocampal network reveal that Abeta42 increases intracellular Ca2+ concentration by 46% and inhibits firing discharge by 19%. More precisely, Abeta42 differently regulates ryanodine (RyRs), NMDA receptors (NMDARs), and voltage gated calcium channels (VGCCs) by increasing Ca2+ release through RyRs and inhibiting Ca2+ influx through NMDARs and VGCCs. The overall increased intracellular Ca2+ concentration causes stimulation of K+ current carried by big conductance Ca2+ activated potassium (BK) channels and hippocampal network firing inhibition. We conclude that Abeta42 alters neuronal function by means of at least 4 main targets: RyRs, NMDARs, VGCCs, and BK channels. The development of selective modulators of these channels may in turn be useful for developing effective therapies that could enhance the quality of life of AD patients during the early onset of the pathology.
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Affiliation(s)
- Daniela Gavello
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Chiara Calorio
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Claudio Franchino
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Federico Cesano
- Department of Chemistry Via Pietro Giuria 7, Torino University, 10125 Torino, Italy
| | - Valentina Carabelli
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Emilio Carbone
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Andrea Marcantoni
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
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14
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Park P, Kang H, Sanderson TM, Bortolotto ZA, Georgiou J, Zhuo M, Kaang BK, Collingridge GL. On the Role of Calcium-Permeable AMPARs in Long-Term Potentiation and Synaptic Tagging in the Rodent Hippocampus. Front Synaptic Neurosci 2019; 11:4. [PMID: 30923499 PMCID: PMC6426746 DOI: 10.3389/fnsyn.2019.00004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/01/2019] [Indexed: 12/21/2022] Open
Abstract
Classically, long-term potentiation (LTP) at hippocampal CA1 synapses is triggered by the synaptic activation of NMDA receptors (NMDARs). More recently, it has been shown that calcium-permeable (CP)-AMPARs can also trigger synaptic plasticity at these synapses. Specifically, their activation is required for the PKA and protein synthesis dependent component of LTP that is typically induced by delivery of spaced trains of high frequency stimulation. Here we present new data that build upon these ideas, including the requirement for low frequency synaptic activation and NMDAR dependence. We also show that a spaced theta burst stimulation (sTBS) protocol induces a heterosynaptic potentiation of baseline responses via activation of CP-AMPARs. Finally, we present data that implicate CP-AMPARs in synaptic tagging and capture, a fundamental process that is associated with the protein synthesis-dependent component of LTP. We have studied how a sTBS can augment the level of LTP generated by a weak TBS (wTBS), delivered 30 min later to an independent input. We show that inhibition of CP-AMPARs during the sTBS eliminates, and that inhibition of CP-AMPARs during the wTBS reduces, this facilitation of LTP. These data suggest that CP-AMPARs are crucial for the protein synthesis-dependent component of LTP and its heterosynaptic nature.
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Affiliation(s)
- Pojeong Park
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Heather Kang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Thomas M Sanderson
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Zuner A Bortolotto
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Min Zhuo
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Graham L Collingridge
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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15
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Montes de Oca Balderas P. Flux-Independent NMDAR Signaling: Molecular Mediators, Cellular Functions, and Complexities. Int J Mol Sci 2018; 19:ijms19123800. [PMID: 30501045 PMCID: PMC6321296 DOI: 10.3390/ijms19123800] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/21/2022] Open
Abstract
The glutamate (Glu) N-methyl-d-aspartate (NMDA) receptor (NMDAR) plays a critical role in synaptic communication given mainly by its ionotropic function that permeates Ca2+. This in turn activates calmodulin that triggers CaMKII, MAPK, CREB, and PI3K pathways, among others. However, NMDAR signaling is more complex. In the last two decades several groups have shown that the NMDAR also elicits flux-independent signaling (f-iNMDARs). It has been demonstrated that agonist (Glu or NMDA) or co-agonist (Glycine or d-Serine) bindings initiate intracellular events, including conformational changes, exchange of molecular interactions, release of second messengers, and signal transduction, that result in different cellular events including endocytosis, LTD, cell death, and neuroprotection, among others. Interestingly, f-iNMDARs has also been observed in pathological conditions and non-neuronal cells. Here, the molecular and cellular events elicited by these flux-independent actions (non-canonical or metabotropic-like) of the NMDAR are reviewed. Considering the NMDAR complexity, it is possible that these flux-independent events have a more relevant role in intracellular signaling that has been disregarded for decades. Moreover, considering the wide expression and function of the NMDAR in non-neuronal cells and other tissues beyond the nervous system and some evolutionary traits, f-iNMDARs calls for a reconsideration of how we understand the biology of this complex receptor.
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Affiliation(s)
- Pavel Montes de Oca Balderas
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM. Av. Universidad 3000, C.U. Coyoacán, Ciudad de México. C.P. 04510, Mexico.
- Unidad de Neurobiología Dinámica, Departamento de Neuroquímica, INNN. Av. Insurgentes Sur #3877 Col. La Fama, Ciudad de México. C.P. 14269, Mexico.
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16
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Lodge D, Watkins JC, Bortolotto ZA, Jane DE, Volianskis A. The 1980s: D-AP5, LTP and a Decade of NMDA Receptor Discoveries. Neurochem Res 2018; 44:516-530. [PMID: 30284673 PMCID: PMC6420420 DOI: 10.1007/s11064-018-2640-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/12/2018] [Accepted: 09/17/2018] [Indexed: 01/02/2023]
Abstract
In the 1960s and 70s, biochemical and pharmacological evidence was pointing toward glutamate as a synaptic transmitter at a number of distinct receptor classes, known as NMDA and non-NMDA receptors. The field, however, lacked a potent and highly selective antagonist to block these putative postsynaptic receptors. So, the discoveries in the early 1980s of d-AP5 as a selective NMDA receptor antagonist and of its ability to block synaptic events and plasticity were a major breakthrough leading to an explosion of knowledge about this receptor subtype. During the next 10 years, the role of NMDA receptors was established in synaptic transmission, long-term potentiation, learning and memory, epilepsy, pain, among others. Hints at pharmacological heterogeneity among NMDA receptors were followed by the cloning of separate subunits. The purpose of this review is to recognize the important contributions made in the 1980s by Graham L. Collingridge and other key scientists to the advances in our understanding of the functions of NMDA receptors throughout the central nervous system.
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Affiliation(s)
- D Lodge
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - J C Watkins
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Z A Bortolotto
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - D E Jane
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - A Volianskis
- School of Clinical Sciences, University of Bristol, Bristol, UK.
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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17
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Dual action of L-Lactate on the activity of NR2B-containing NMDA receptors: from potentiation to neuroprotection. Sci Rep 2018; 8:13472. [PMID: 30194439 PMCID: PMC6128851 DOI: 10.1038/s41598-018-31534-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 08/21/2018] [Indexed: 12/16/2022] Open
Abstract
L-Lactate is a positive modulator of NMDAR-mediated signaling resulting in plasticity gene induction and memory consolidation. However, L-Lactate is also able to protect neurons against excito-toxic NMDAR activity, an indication of a mitigating action of L-Lactate on NMDA signaling. In this study, we provide experimental evidence that resolves this apparent paradox. Transient co-application of glutamate/glycine (1 μM/100 μM; 2 min) in primary cultures of mouse cortical neurons triggers a NMDA-dependent Ca2+ signal positively modulated by L-Lactate (10 mM) or DTT (1 mM) but decreased by Pyruvate (10 mM). This L-Lactate and DTT-induced potentiation is blocked by Ifenprodil (2 μM), a specific blocker of NMDARs containing NR2B sub-units. In contrast, co-application of glutamate/glycine (1 mM/100 μM; 2 min) elicits a NMDAR-dependent excitotoxic death in 49% of neurons. L-Lactate and Pyruvate significantly reduce this rate of cell death processes (respectively to 23% and 9%) while DTT has no effect (54% of neuronal death). This L-Lactate-induced neuroprotection is blocked by carbenoxolone and glibenclamide, respectively blockers of pannexins and KATP. In conclusion, our results show that L-Lactate is involved in two distinct and independent pathways defined as NMDAR-mediated potentiation pathway (or NADH pathway) and a neuroprotective pathway (or Pyruvate/ATP pathway), the prevalence of each one depending on the strength of the glutamatergic stimulus.
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18
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Frazier HN, Maimaiti S, Anderson KL, Brewer LD, Gant JC, Porter NM, Thibault O. Calcium's role as nuanced modulator of cellular physiology in the brain. Biochem Biophys Res Commun 2016; 483:981-987. [PMID: 27553276 DOI: 10.1016/j.bbrc.2016.08.105] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/04/2016] [Accepted: 08/18/2016] [Indexed: 12/22/2022]
Abstract
Neuroscientists studying normal brain aging, spinal cord injury, Alzheimer's disease (AD) and other neurodegenerative diseases have focused considerable effort on carefully characterizing intracellular perturbations in calcium dynamics or levels. At the cellular level, calcium is known for controlling life and death and orchestrating most events in between. For many years, intracellular calcium has been recognized as an essential ion associated with nearly all cellular functions from cell growth to degeneration. Often the emphasis is on the negative impact of calcium dysregulation and the typical worse-case-scenario leading inevitably to cell death. However, even high amplitude calcium transients, when executed acutely, can alter neuronal communication and synaptic strength in positive ways, without necessarily killing neurons. Here, we focus on the evidence that calcium has a subtle and distinctive role in shaping and controlling synaptic events that underpin neuronal communication and that these subtle changes in aging or AD may contribute to cognitive decline. We emphasize that calcium imaging in dendritic components is ultimately necessary to directly test for the presence of age- or disease-associated alterations during periods of synaptic activation.
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Affiliation(s)
- Hilaree N Frazier
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Shaniya Maimaiti
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Katie L Anderson
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Lawrence D Brewer
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - John C Gant
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Nada M Porter
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Olivier Thibault
- UKMC, MS-313, Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA.
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19
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Role of postsynaptic inositol 1, 4, 5-trisphosphate receptors in depotentiation in guinea pig hippocampal CA1 neurons. Brain Res 2016; 1642:154-162. [DOI: 10.1016/j.brainres.2016.03.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/12/2016] [Accepted: 03/22/2016] [Indexed: 11/19/2022]
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20
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Abstract
Long-lasting, activity-dependent changes in the efficacy of synaptic transmission are considered to be of fundamental importance for the storage of information and for the development of neural circuitry. The leading experimental model for such a change has been long-term potentiation (LTP), a long-lasting increase in synaptic strength. Intensive experimental analysis of LTP in the hippocampus has resulted in a detailed description of the initial steps responsible for its generation. Recently, a form of long-term depression (LTD) in the hippocampus has been described and examined. It shares several mechanistic features with LTP and appears to be able to reverse LTP. The intracellular second messenger systems that are required to generate and maintain LTP and LTD have been difficult to identify definitively. Leading candidates include diffusible intercellular messengers as well as protein kinases and protein phosphatases, the activities of which may converge at the level of specific phosphoproteins. In addition to delineating the cellular mechanisms under lying LTP and LTD, investigators also are beginning to clarify the roles they play in real learning and memory. The Neuroscientist 1:35-42, 1995
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Affiliation(s)
- Robert C. Malenka
- Center for Neurobiology and Psychiatry Departments of
Psychiatry and Physiology University of California San Francisco, California
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21
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Abstract
The anterior cingulate cortex (ACC) is activated in both acute and chronic pain. In this Review, we discuss increasing evidence from rodent studies that ACC activation contributes to chronic pain states and describe several forms of synaptic plasticity that may underlie this effect. In particular, one form of long-term potentiation (LTP) in the ACC, which is triggered by the activation of NMDA receptors and expressed by an increase in AMPA-receptor function, sustains the affective component of the pain state. Another form of LTP in the ACC, which is triggered by the activation of kainate receptors and expressed by an increase in glutamate release, may contribute to pain-related anxiety.
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22
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Fujii S, Yamazaki Y, Goto JI, Fujiwara H, Mikoshiba K. Prior activation of inositol 1,4,5-trisphosphate receptors suppresses the subsequent induction of long-term potentiation in hippocampal CA1 neurons. Learn Mem 2016; 23:208-20. [PMID: 27084928 PMCID: PMC4836634 DOI: 10.1101/lm.041053.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/25/2016] [Indexed: 11/24/2022]
Abstract
We investigated the role of inositol 1,4,5-trisphosphate receptors (IP3Rs) activated by preconditioning low-frequency afferent stimulation (LFS) in the subsequent induction of long-term potentiation (LTP) in CA1 neurons in hippocampal slices from mature guinea pigs. Induction of LTP in the field excitatory postsynaptic potential or the population spike by the delivery of high-frequency stimulation (HFS, a tetanus of 100 pulses at 100 Hz) to the Schaffer collateral-commissural pathway to CA1 neuron synapses was suppressed when group I metabotropic glutamate receptors (mGluRs) were activated prior to the delivery of HFS. LTP induction was also suppressed when CA1 synapses were preconditioned 60 min before HFS by LFS of 1000 pulses at 1 Hz and this effect was inhibited when the test stimulation delivered at 0.05 Hz was either halted or applied in the presence of an antagonist ofN-methyl-d-aspartate receptors, group I mGluRs, or IP3Rs during a 20-min period from 20 to 40 min after the end of LFS. Furthermore, blockade of group I mGluRs or IP3Rs immediately before the delivery of HFS overcame the effects of the preconditioning LFS on LTP induction. These results suggest that, in CA1 neurons, after a preconditioning LFS, activation of group I mGluRs caused by the test stimulation results in IP3Rs activation that leads to a failure of LTP induction.
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Affiliation(s)
- Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Jun-Ichi Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Hiroki Fujiwara
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
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23
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Lee KFH, Soares C, Thivierge JP, Béïque JC. Correlated Synaptic Inputs Drive Dendritic Calcium Amplification and Cooperative Plasticity during Clustered Synapse Development. Neuron 2016; 89:784-99. [PMID: 26853305 DOI: 10.1016/j.neuron.2016.01.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 09/21/2015] [Accepted: 12/21/2015] [Indexed: 11/29/2022]
Abstract
The mechanisms that instruct the assembly of fine-scale features of synaptic connectivity in neural circuits are only beginning to be understood. Using whole-cell electrophysiology, two-photon calcium imaging, and glutamate uncaging in hippocampal slices, we discovered a functional coupling between NMDA receptor activation and ryanodine-sensitive intracellular calcium release that dominates the spatiotemporal dynamics of activity-dependent calcium signals during synaptogenesis. This developmentally regulated calcium amplification mechanism was tuned to detect and bind spatially clustered and temporally correlated synaptic inputs and enacted a local cooperative plasticity rule between coactive neighboring synapses. Consistent with the hypothesis that synapse maturation is spatially regulated, we observed clustering of synaptic weights in developing dendritic arbors. These results reveal developmental features of NMDA receptor-dependent calcium dynamics and local plasticity rules that are suited to spatially guide synaptic connectivity patterns in emerging neural networks.
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Affiliation(s)
- Kevin F H Lee
- Neuroscience Graduate Program, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Cary Soares
- Neuroscience Graduate Program, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Jean-Philippe Thivierge
- Centre for Neural Dynamics, University of Ottawa, Ottawa, ON K1H 8M5, Canada; School of Psychology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Jean-Claude Béïque
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Centre for Neural Dynamics, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
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24
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Tigaret CM, Olivo V, Sadowski JHLP, Ashby MC, Mellor JR. Coordinated activation of distinct Ca(2+) sources and metabotropic glutamate receptors encodes Hebbian synaptic plasticity. Nat Commun 2016; 7:10289. [PMID: 26758963 PMCID: PMC4735496 DOI: 10.1038/ncomms10289] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/26/2015] [Indexed: 01/10/2023] Open
Abstract
At glutamatergic synapses, induction of associative synaptic plasticity requires time-correlated presynaptic and postsynaptic spikes to activate postsynaptic NMDA receptors (NMDARs). The magnitudes of the ensuing Ca2+ transients within dendritic spines are thought to determine the amplitude and direction of synaptic change. In contrast, we show that at mature hippocampal Schaffer collateral synapses the magnitudes of Ca2+ transients during plasticity induction do not match this rule. Indeed, LTP induced by time-correlated pre- and postsynaptic spikes instead requires the sequential activation of NMDARs followed by voltage-sensitive Ca2+ channels within dendritic spines. Furthermore, LTP requires inhibition of SK channels by mGluR1, which removes a negative feedback loop that constitutively regulates NMDARs. Therefore, rather than being controlled simply by the magnitude of the postsynaptic calcium rise, LTP induction requires the coordinated activation of distinct sources of Ca2+ and mGluR1-dependent facilitation of NMDAR function. During STDP, the magnitude of postsynaptic Ca2+ transients is hypothesized to determine the strength of synaptic plasticity. Here, the authors find that STDP in mature hippocampal synapses does not obey this rule but instead relies on the coordinated activation of NMDARs and VGCCs and their regulation by mGluRs and SK channels.
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Affiliation(s)
- Cezar M Tigaret
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Valeria Olivo
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Josef H L P Sadowski
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Michael C Ashby
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jack R Mellor
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK
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25
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Yamazaki Y, Fujii S, Goto JI, Fujiwara H, Mikoshiba K. Activation of inositol 1,4,5-trisphosphate receptors during preconditioning low-frequency stimulation suppresses subsequent induction of long-term potentiation in hippocampal CA1 neurons. Neuroscience 2015; 311:195-206. [PMID: 26500182 DOI: 10.1016/j.neuroscience.2015.10.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/07/2015] [Accepted: 10/15/2015] [Indexed: 12/30/2022]
Abstract
We investigated the role of inositol 1,4,5-trisphosphate receptors (IP3Rs) activated during preconditioning low-frequency stimulation (LFS) in the subsequent high-frequency stimulation (HFS)-induced induction of long-term potentiation (LTP) in CA1 neurons in hippocampal slices from mature guinea pigs. Induction of LTP in the field excitatory postsynaptic potential (EPSP) or the population spike (PS) by delivery of HFS (a tetanus of 100 pulses at 100 Hz) to the Schaffer collateral-commissural pathway to CA1 neuron synapses was suppressed when the CA1 synapses were preconditioned by LFS of 1000 pulses at 1 Hz. This effect was inhibited when the preconditioning LFS was applied in the presence of an N-methyl-D-aspartate receptors (NMDARs) antagonist, a metabotropic glutamate receptor (mGluR) antagonist, IP3R antagonist, a calmodulin-dependent kinase II inhibitor or a calcineurin inhibitor. Furthermore, blockade of group I mGluRs immediately before the delivery of HFS blocked the inhibitory effect of the preconditioning LFS on subsequent induction of LTP by HFS. These results suggest that, in hippocampal CA1 neuron synapses, co-activation of NMDARs and IP3Rs during a preconditioning LFS results in both phosphorylation and dephosphorylation events that lead to prolonged activation of group I mGluRs that is responsible for the failure of LTP induction.
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Affiliation(s)
- Y Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - S Fujii
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan; Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan.
| | - J-I Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan; Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - H Fujiwara
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - K Mikoshiba
- Laboratory for Developmental Neurobiology, Riken Brain Science Institute, Wako, Saitama 351-0198, Japan
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26
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Arrázola MS, Silva-Alvarez C, Inestrosa NC. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario. Front Cell Neurosci 2015; 9:166. [PMID: 25999816 PMCID: PMC4419851 DOI: 10.3389/fncel.2015.00166] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/14/2015] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as “mitochondrial dynamics” is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration.
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Affiliation(s)
- Macarena S Arrázola
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile Santiago, Chile
| | - Carmen Silva-Alvarez
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile Santiago, Chile
| | - Nibaldo C Inestrosa
- Facultad de Ciencias Biológicas, Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile Santiago, Chile ; Center for Healthy Brain Aging, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia ; Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes Punta Arenas, Chile ; Centro UC Síndrome de Down, Pontificia Universidad Católica de Chile Santiago, Chile
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Yasuda H, Mukai H. Turning off of GluN2B subunits and turning on of CICR in hippocampal LTD induction after developmental GluN2 subunit switch. Hippocampus 2015; 25:1274-84. [PMID: 25727316 DOI: 10.1002/hipo.22435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2015] [Indexed: 11/08/2022]
Abstract
NMDA receptors (NMDARs) are essential for the induction of synaptic plasticity that mediates activity-dependent refinement of neural circuits during development. GluN2B subunits of NMDARs are abundant at synapses in the immature hippocampus and begin to be replaced by GluN2A subunits with the help of casein kinase 2 activity in the second postnatal week, the critical period for the GluN2 subunit switch (Sanz-Clemente et al. (2000) Neuron 67:984-996). However, the physiological role of GluN2B subunits in the hippocampus during this critical period has not been elucidated. Here, we report that GluN2B subunits mediate the induction of long-term depression (LTD) in the CA1 region of the hippocampus only until this period. Ifenprodil and Ro25-6981, selective inhibitors of NMDARs containing GluN2B subunits, blocked LTD in postnatal Day 11-14 (P11-14) rat hippocampal slices but not in P18-22 hippocampus. Just a few days after P14, synaptic NMDAR currents became narrower than those at P11-14, and calcium influx through NMDARs must be reduced. We found that calcium-induced calcium release (CICR) through ryanodine receptors starts to support the induction of NMDAR-dependent LTD at P18-22. Intracellular application of thapsigargin and ryanodine, inhibitors of Ca2+ -ATP pumps on internal stores and ryanodine receptors, respectively, did not at all affect LTD in the hippocampus at P11-14 but completely blocked LTD in the P18-22 hippocampus. Therefore, calcium influx through NMDAR with GluN2B subunits is sufficient to induce LTD at P11-14, after which CICR compensates for the decrease in calcium influx during LTD induction.
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Affiliation(s)
- Hiroki Yasuda
- Education and Research Support Center, Gunma University Graduate School of Medicine, Maebashi, Japan
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28
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Volianskis A, France G, Jensen MS, Bortolotto ZA, Jane DE, Collingridge GL. Long-term potentiation and the role of N-methyl-D-aspartate receptors. Brain Res 2015; 1621:5-16. [PMID: 25619552 PMCID: PMC4563944 DOI: 10.1016/j.brainres.2015.01.016] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 10/31/2022]
Abstract
N-methyl-D-aspartate receptors (NMDARs) are known for their role in the induction of long-term potentiation (LTP). Here we start by reviewing the early evidence for their role in LTP at CA1 synapses in the hippocampus. We then discuss more recent evidence that NMDAR dependent synaptic plasticity at these synapses can be separated into mechanistically distinct components. An initial phase of the synaptic potentiation, which is generally termed short-term potentiation (STP), decays in an activity-dependent manner and comprises two components that differ in their kinetics and NMDAR subtype dependence. The faster component involves activation of GluN2A and GluN2B subunits whereas the slower component involves activation of GluN2B and GluN2D subunits. The stable phase of potentiation, commonly referred to as LTP, requires activation of primarily triheteromeric NMDARs containing both GluN2A and GluN2B subunits. In new work, we compare STP with a rebound potentiation (RP) that is induced by NMDA application and conclude that they are different phenomena. We also report that NMDAR dependent long-term depression (NMDAR-LTD) is sensitive to a glycine site NMDAR antagonist. We conclude that NMDARs are not synonymous for either LTP or memory. Whilst important for the induction of LTP at many synapses in the CNS, not all forms of LTP require the activation of NMDARs. Furthermore, NMDARs mediate the induction of other forms of synaptic plasticity and are important for synaptic transmission. It is, therefore, not possible to equate NMDARs with LTP though they are intimately linked. This article is part of a Special Issue entitled SI: Brain and Memory.
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Affiliation(s)
- Arturas Volianskis
- Center for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, United Kingdom.
| | - Grace France
- Center for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, United Kingdom
| | | | - Zuner A Bortolotto
- Center for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, United Kingdom
| | - David E Jane
- Center for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, United Kingdom
| | - Graham L Collingridge
- Center for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, United Kingdom.
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29
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Alford ST, Alpert MH. A synaptic mechanism for network synchrony. Front Cell Neurosci 2014; 8:290. [PMID: 25278839 PMCID: PMC4166887 DOI: 10.3389/fncel.2014.00290] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/31/2014] [Indexed: 01/06/2023] Open
Abstract
Within neural networks, synchronization of activity is dependent upon the synaptic connectivity of embedded microcircuits and the intrinsic membrane properties of their constituent neurons. Synaptic integration, dendritic Ca2+ signaling, and non-linear interactions are crucial cellular attributes that dictate single neuron computation, but their roles promoting synchrony and the generation of network oscillations are not well understood, especially within the context of a defined behavior. In this regard, the lamprey spinal central pattern generator (CPG) stands out as a well-characterized, conserved vertebrate model of a neural network (Smith et al., 2013a), which produces synchronized oscillations in which neural elements from the systems to cellular level that control rhythmic locomotion have been determined. We review the current evidence for the synaptic basis of oscillation generation with a particular emphasis on the linkage between synaptic communication and its cellular coupling to membrane processes that control oscillatory behavior of neurons within the locomotor network. We seek to relate dendritic function found in many vertebrate systems to the accessible lamprey central nervous system in which the relationship between neural network activity and behavior is well understood. This enables us to address how Ca2+ signaling in spinal neuron dendrites orchestrate oscillations that drive network behavior.
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Affiliation(s)
- Simon T Alford
- Department of Biological Sciences, University of Illinois at Chicago Chicago, IL, USA
| | - Michael H Alpert
- Department of Biological Sciences, University of Illinois at Chicago Chicago, IL, USA
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30
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Paula-Lima AC, Adasme T, Hidalgo C. Contribution of Ca2+ release channels to hippocampal synaptic plasticity and spatial memory: potential redox modulation. Antioxid Redox Signal 2014; 21:892-914. [PMID: 24410659 DOI: 10.1089/ars.2013.5796] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE Memory is an essential human cognitive function. Consequently, to unravel the cellular and molecular mechanisms responsible for the synaptic plasticity events underlying memory formation, storage and loss represents a major challenge of present-day neuroscience. RECENT ADVANCES This review article first describes the wide-ranging functions played by intracellular Ca2+ signals in the activity-dependent synaptic plasticity processes underlying hippocampal spatial memory, and next, it focuses on how the endoplasmic reticulum Ca2+ release channels, the ryanodine receptors, and the inositol 1,4,5-trisphosphate receptors contribute to these processes. We present a detailed examination of recent evidence supporting the key role played by Ca2+ release channels in synaptic plasticity, including structural plasticity, and the formation/consolidation of spatial memory in the hippocampus. CRITICAL ISSUES Changes in cellular oxidative state particularly affect the function of Ca2+ release channels and alter hippocampal synaptic plasticity and the associated memory processes. Emphasis is placed in this review on how defective Ca2+ release, presumably due to increased levels of reactive oxygen species, may cause the hippocampal functional defects that are associated to aging and Alzheimer's disease (AD). FUTURE DIRECTIONS Additional studies should examine the precise molecular mechanisms by which Ca2+ release channels contribute to hippocampal synaptic plasticity and spatial memory formation/consolidation. Future studies should test whether redox-modified Ca2+ release channels contribute toward generating the intracellular Ca2+ signals required for sustained synaptic plasticity and hippocampal spatial memory, and whether loss of redox balance and oxidative stress, by altering Ca2+ release channel function, presumably contribute to the abnormal memory processes that occur during aging and AD.
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Affiliation(s)
- Andrea C Paula-Lima
- 1 Faculty of Dentistry, Institute for Research in Dental Sciences, Universidad de Chile , Santiago, Chile
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31
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Rapid regulation of endoplasmic reticulum dynamics in dendritic spines by NMDA receptor activation. Mol Brain 2014; 7:60. [PMID: 25242397 PMCID: PMC4237958 DOI: 10.1186/s13041-014-0060-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/12/2014] [Indexed: 01/24/2023] Open
Abstract
Endoplasmic reticulum (ER) is motile within dendritic spines, but the mechanisms underlying its regulation are poorly understood. To address this issue, we have simultaneously imaged morphology and ER content of dendritic spines in cultured dissociated mouse hippocampal neurons. Over a 10 min period, spines were highly dynamic, with spines both increasing and decreasing in volume. ER was present in approximately 50% of spines and was also highly dynamic, with a net increase over this period of time. Inhibition of the endogenous activation of NMDA receptors resulted in a reduction in ER growth. Conversely, augmentation of the synaptic activation of NMDA receptors, by elimination of striatal-enriched protein tyrosine phosphatase (STEP), resulted in enhanced ER growth. Therefore, NMDA receptors rapidly regulate spine ER dynamics.
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32
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Whitehead G, Jo J, Hogg EL, Piers T, Kim DH, Seaton G, Seok H, Bru-Mercier G, Son GH, Regan P, Hildebrandt L, Waite E, Kim BC, Kerrigan TL, Kim K, Whitcomb DJ, Collingridge GL, Lightman SL, Cho K. Acute stress causes rapid synaptic insertion of Ca2+ -permeable AMPA receptors to facilitate long-term potentiation in the hippocampus. ACTA ACUST UNITED AC 2013; 136:3753-65. [PMID: 24271563 PMCID: PMC3859225 DOI: 10.1093/brain/awt293] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The neuroendocrine response to episodes of acute stress is crucial for survival whereas the prolonged response to chronic stress can be detrimental. Learning and memory are particularly susceptible to stress with cognitive deficits being well characterized consequences of chronic stress. Although there is good evidence that acute stress can enhance cognitive performance, the mechanism(s) for this are unclear. We find that hippocampal slices, either prepared from rats following 30 min restraint stress or directly exposed to glucocorticoids, exhibit an N-methyl-d-aspartic acid receptor-independent form of long-term potentiation. We demonstrate that the mechanism involves an NMDA receptor and PKA-dependent insertion of Ca2+-permeable AMPA receptors into synapses. These then trigger the additional NMDA receptor-independent form of LTP during high frequency stimulation.
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Affiliation(s)
- Garry Whitehead
- 1 Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
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Plotkin JL, Shen W, Rafalovich I, Sebel LE, Day M, Chan CS, Surmeier DJ. Regulation of dendritic calcium release in striatal spiny projection neurons. J Neurophysiol 2013; 110:2325-36. [PMID: 23966676 DOI: 10.1152/jn.00422.2013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The induction of corticostriatal long-term depression (LTD) in striatal spiny projection neurons (SPNs) requires coactivation of group I metabotropic glutamate receptors (mGluRs) and L-type Ca(2+) channels. This combination leads to the postsynaptic production of endocannabinoids that act presynaptically to reduce glutamate release. Although the necessity of coactivation is agreed upon, why it is necessary in physiologically meaningful settings is not. The studies described here attempt to answer this question by using two-photon laser scanning microscopy and patch-clamp electrophysiology to interrogate the dendritic synapses of SPNs in ex vivo brain slices from transgenic mice. These experiments revealed that postsynaptic action potentials induce robust ryanodine receptor (RYR)-dependent Ca(2+)-induced-Ca(2+) release (CICR) in SPN dendritic spines. Depolarization-induced opening of voltage-gated Ca(2+) channels was necessary for CICR. CICR was more robust in indirect pathway SPNs than in direct pathway SPNs, particularly in distal dendrites. Although it did not increase intracellular Ca(2+) concentration alone, group I mGluR activation enhanced CICR and slowed Ca(2+) clearance, extending the activity-evoked intraspine transient. The mGluR modulation of CICR was sensitive to antagonism of inositol trisphosphate receptors, RYRs, src kinase, and Cav1.3 L-type Ca(2+) channels. Uncaging glutamate at individual spines effectively activated mGluRs and facilitated CICR induced by back-propagating action potentials. Disrupting CICR by antagonizing RYRs prevented the induction of corticostriatal LTD with spike-timing protocols. In contrast, mGluRs had no effect on the induction of long-term potentiation. Taken together, these results make clearer how coactivation of mGluRs and L-type Ca(2+) channels promotes the induction of activity-dependent LTD in SPNs.
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Affiliation(s)
- Joshua L Plotkin
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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34
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Bliss TVP, Collingridge GL. Expression of NMDA receptor-dependent LTP in the hippocampus: bridging the divide. Mol Brain 2013; 6:5. [PMID: 23339575 PMCID: PMC3562207 DOI: 10.1186/1756-6606-6-5] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Accepted: 12/27/2012] [Indexed: 12/17/2022] Open
Abstract
A consensus has famously yet to emerge on the locus and mechanisms underlying the expression of the canonical NMDA receptor-dependent form of LTP. An objective assessment of the evidence leads us to conclude that both presynaptic and postsynaptic expression mechanisms contribute to this type of synaptic plasticity.
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Affiliation(s)
- Tim V P Bliss
- Division of Neurophysiology, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
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35
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García-Osta A, Cuadrado-Tejedor M, García-Barroso C, Oyarzábal J, Franco R. Phosphodiesterases as therapeutic targets for Alzheimer's disease. ACS Chem Neurosci 2012; 3:832-44. [PMID: 23173065 DOI: 10.1021/cn3000907] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/01/2012] [Indexed: 01/10/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia among the elderly. In AD patients, memory loss is accompanied by the formation of beta-amyloid plaques and the appearance of tau in a pathological form. Given the lack of effective treatments for AD, the development of new management strategies for these patients is critical. The continued failure to find effective therapies using molecules aimed at addressing the anti-beta amyloid pathology has led researchers to focus on other non-amyloid-based approaches to restore memory function. Promising non-amyloid related candidate targets include phosphosdiesterases (PDEs), and indeed, Rolipram, a specific PDE4 inhibitor, was the first compound found to effectively restore cognitive deficits in animal models of AD. More recently, PDE5 inhibitors have also been shown to effectively restore memory function. Accordingly, inhibitors of other members of the PDE family may also improve memory performance in AD and non-AD animal models. Hence, in this review, we will summarize the data supporting the use of PDE inhibitors as cognitive enhancers and we will discuss the possible mechanisms of action underlying these effects. We shall also adopt a medicinal chemistry perspective that leads us to propose the most promising PDE candidates on the basis of inhibitor selectivity, brain distribution, and mechanism of action.
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Affiliation(s)
- Ana García-Osta
- Molecular and Cell Neuropharmacology
Laboratory, Neurosciences Division, CIMA (Centro de investigación Médica Aplicada), Avda Pio
XII, Pamplona, Spain
| | - Mar Cuadrado-Tejedor
- Molecular and Cell Neuropharmacology
Laboratory, Neurosciences Division, CIMA (Centro de investigación Médica Aplicada), Avda Pio
XII, Pamplona, Spain
| | - Carolina García-Barroso
- Molecular and Cell Neuropharmacology
Laboratory, Neurosciences Division, CIMA (Centro de investigación Médica Aplicada), Avda Pio
XII, Pamplona, Spain
| | - Julen Oyarzábal
- Molecular and Cell Neuropharmacology
Laboratory, Neurosciences Division, CIMA (Centro de investigación Médica Aplicada), Avda Pio
XII, Pamplona, Spain
- Small
Molecule Discovery Platform, CIMA (Centro
de investigación Médica
Aplicada), Avda Pio XII, Pamplona, Spain
| | - Rafael Franco
- Molecular and Cell Neuropharmacology
Laboratory, Neurosciences Division, CIMA (Centro de investigación Médica Aplicada), Avda Pio
XII, Pamplona, Spain
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Early presynaptic and postsynaptic calcium signaling abnormalities mask underlying synaptic depression in presymptomatic Alzheimer's disease mice. J Neurosci 2012; 32:8341-53. [PMID: 22699914 DOI: 10.1523/jneurosci.0936-12.2012] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD)-linked presenilin (PS) mutations result in pronounced endoplasmic reticulum calcium disruptions that occur before detectable histopathology and cognitive deficits. More subtly, these early AD-linked calcium alterations also reset neurophysiological homeostasis, such that calcium-dependent presynaptic and postsynaptic signaling appear functionally normal yet are actually operating under aberrant calcium signaling systems. In these 3xTg-AD mouse brains, upregulated ryanodine receptor (RyR) activity is associated with a shift toward synaptic depression, likely through a reduction in presynaptic vesicle stores and increased postsynaptic outward currents through small-conductance calcium-activated potassium SK2 channels. The deviant RyR-calcium involvement in the 3xTg-AD mice also compensates for an intrinsic predisposition for hippocampal long-term depression (LTD) and reduced long-term potentiation (LTP). In this study, we detail the impact of disrupted RyR-mediated calcium stores on synaptic transmission properties, LTD, and calcium-activated membrane channels of hippocampal CA1 pyramidal neurons in presymptomatic 3xTg-AD mice. Using electrophysiological recordings in young 3xTg-AD and nontransgenic (NonTg) hippocampal slices, we show that increased RyR-evoked calcium release in 3xTg-AD mice "normalizes" an altered synaptic transmission system operating under a shifted homeostatic state that is not present in NonTg mice. In the process, we uncover compensatory signaling mechanisms recruited early in the disease process that counterbalance the disrupted RyR-calcium dynamics, namely increases in presynaptic spontaneous vesicle release, altered probability of vesicle release, and upregulated postsynaptic SK channel activity. Because AD is increasingly recognized as a "synaptic disease," calcium-mediated signaling alterations may serve as a proximal trigger for the synaptic degradation driving the cognitive loss in AD.
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37
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Xie W, Adayev T, Zhu H, Wegiel J, Wieraszko A, Hwang YW. Activity-Dependent Phosphorylation of Dynamin 1 at Serine 857. Biochemistry 2012; 51:6786-96. [DOI: 10.1021/bi2017798] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wen Xie
- Department of Biology, College of Staten Island, City University of New York, Staten Island, New York 10314,
United States
| | | | | | | | - Andrzej Wieraszko
- Department of Biology, College of Staten Island, City University of New York, Staten Island, New York 10314,
United States
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38
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Early calcium dysregulation in Alzheimer's disease: setting the stage for synaptic dysfunction. SCIENCE CHINA-LIFE SCIENCES 2011; 54:752-62. [PMID: 21786198 DOI: 10.1007/s11427-011-4205-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 05/30/2011] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease (AD) is an irreversible and progressive neurodegenerative disorder with no known cure or clear understanding of the mechanisms involved in the disease process. Amyloid plaques, neurofibrillary tangles and neuronal loss, though characteristic of AD, are late stage markers whose impact on the most devastating aspect of AD, namely memory loss and cognitive deficits, are still unclear. Recent studies demonstrate that structural and functional breakdown of synapses may be the underlying factor in AD-linked cognitive decline. One common element that presents with several features of AD is disrupted neuronal calcium signaling. Increased intracellular calcium levels are functionally linked to presenilin mutations, ApoE4 expression, amyloid plaques, tau tangles and synaptic dysfunction. In this review, we discuss the role of AD-linked calcium signaling alterations in neurons and how this may be linked to synaptic dysfunctions at both early and late stages of the disease.
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39
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Stutzmann GE, Mattson MP. Endoplasmic reticulum Ca(2+) handling in excitable cells in health and disease. Pharmacol Rev 2011; 63:700-27. [PMID: 21737534 DOI: 10.1124/pr.110.003814] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is a morphologically and functionally diverse organelle capable of integrating multiple extracellular and internal signals and generating adaptive cellular responses. It plays fundamental roles in protein synthesis and folding and in cellular responses to metabolic and proteotoxic stress. In addition, the ER stores and releases Ca(2+) in sophisticated scenarios that regulate a range of processes in excitable cells throughout the body, including muscle contraction and relaxation, endocrine regulation of metabolism, learning and memory, and cell death. One or more Ca(2+) ATPases and two types of ER membrane Ca(2+) channels (inositol trisphosphate and ryanodine receptors) are the major proteins involved in ER Ca(2+) uptake and release, respectively. There are also direct and indirect interactions of ER Ca(2+) stores with plasma membrane and mitochondrial Ca(2+)-regulating systems. Pharmacological agents that selectively modify ER Ca(2+) release or uptake have enabled studies that revealed many different physiological roles for ER Ca(2+) signaling. Several inherited diseases are caused by mutations in ER Ca(2+)-regulating proteins, and perturbed ER Ca(2+) homeostasis is implicated in a range of acquired disorders. Preclinical investigations suggest a therapeutic potential for use of agents that target ER Ca(2+) handling systems of excitable cells in disorders ranging from cardiac arrhythmias and skeletal muscle myopathies to Alzheimer disease.
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Affiliation(s)
- Grace E Stutzmann
- Department of Neuroscience, Rosalind Franklin University/The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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40
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Zoladz PR, Clark B, Warnecke A, Smith L, Tabar J, Talbot JN. Pre-learning stress differentially affects long-term memory for emotional words, depending on temporal proximity to the learning experience. Physiol Behav 2011; 103:467-76. [DOI: 10.1016/j.physbeh.2011.01.016] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 01/06/2011] [Accepted: 01/16/2011] [Indexed: 11/16/2022]
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41
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Muñoz P, Humeres A, Elgueta C, Kirkwood A, Hidalgo C, Núñez MT. Iron mediates N-methyl-D-aspartate receptor-dependent stimulation of calcium-induced pathways and hippocampal synaptic plasticity. J Biol Chem 2011; 286:13382-92. [PMID: 21296883 DOI: 10.1074/jbc.m110.213785] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Iron deficiency hinders hippocampus-dependent learning processes and impairs cognitive performance, but current knowledge on the molecular mechanisms underlying the unique role of iron in neuronal function is sparse. Here, we investigated the participation of iron on calcium signal generation and ERK1/2 stimulation induced by the glutamate agonist N-methyl-D-aspartate (NMDA), and the effects of iron addition/chelation on hippocampal basal synaptic transmission and long-term potentiation (LTP). Addition of NMDA to primary hippocampal cultures elicited persistent calcium signals that required functional NMDA receptors and were independent of calcium influx through L-type calcium channels or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors; NMDA also promoted ERK1/2 phosphorylation and nuclear translocation. Iron chelation with desferrioxamine or inhibition of ryanodine receptor (RyR)-mediated calcium release with ryanodine-reduced calcium signal duration and prevented NMDA-induced ERK1/2 activation. Iron addition to hippocampal neurons readily increased the intracellular labile iron pool and stimulated reactive oxygen species production; the antioxidant N-acetylcysteine or the hydroxyl radical trapper MCI-186 prevented these responses. Iron addition to primary hippocampal cultures kept in calcium-free medium elicited calcium signals and stimulated ERK1/2 phosphorylation; RyR inhibition abolished these effects. Iron chelation decreased basal synaptic transmission in hippocampal slices, inhibited iron-induced synaptic stimulation, and impaired sustained LTP in hippocampal CA1 neurons induced by strong stimulation. In contrast, iron addition facilitated sustained LTP induction after suboptimal tetanic stimulation. Together, these results suggest that hippocampal neurons require iron to generate RyR-mediated calcium signals after NMDA receptor stimulation, which in turn promotes ERK1/2 activation, an essential step of sustained LTP.
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Affiliation(s)
- Pablo Muñoz
- Centro de Neurociencia, Universidad de Valparaíso, Valparaíso 2360102, Chile.
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42
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Chatterjea D, Hamid E, Leonard JP, Alford S. Phosphorylation-state-dependent regulation of NMDA receptor short-term plasticity modifies hippocampal dendritic Ca2+ transients. J Neurophysiol 2010; 104:2203-13. [PMID: 20719921 DOI: 10.1152/jn.01081.2009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-methyl-D-aspartate (NMDA) receptor-mediated currents are enhanced by phosphorylation. We have investigated effects of phosphorylation-dependent short-term plasticity of NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) on the induction of long-term depression (LTD). We confirmed in whole cell clamped CA1 pyramidal neurons that LTD is induced by pairing stimulus protocols. However, after serine-threonine phosphorylation was modified by postsynaptic introduction of a protein phosphatase-1 (PP1) inhibitor, the same pairing protocol evoked long-term potentiation (LTP). We determined effects of modification of phosphatase activity on evoked NMDA EPSCs during LTD induction protocols. During LTD induction, using a protocol pairing depolarization to -40 mV and 0.5 Hz stimulation, NMDA receptor-mediated EPSCs undergo a short-term enhancement at the start of the protocol. In neurons in which PP1 activity was inhibited, this short-term enhancement was markedly amplified. We then investigated the effect of this enhancement on Ca(2+) entry during the start of the LTD induction protocol. Enhancement of NMDA receptor-mediated responses was accompanied by an amplification of induction protocol-evoked Ca(2+) transients. Furthermore, this amplification required synaptic activation during the protocol, consistent with an enhancement of Ca(2+) entry mediated by NMDA receptor activation. The sign of NMDA receptor-mediated long-term plasticity, whether potentiation or depression depends on the amplitude of the synaptic Ca(2+) transient during induction. We conclude that short-term phosphorylation-dependent plasticity of the NMDA receptor-mediated EPSCs contributes significantly to the effect of phosphatase inhibition on the subsequent induction of LTD or LTP.
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Affiliation(s)
- Debika Chatterjea
- Department of Biological Sciences and Laboratory of Integrative Neuroscience, University of Illinois, Chicago, IL 60607, USA
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Popescu AT, Saghyan AA, Nagy FZ, Paré D. Facilitation of corticostriatal plasticity by the amygdala requires Ca2+-induced Ca2+ release in the ventral striatum. J Neurophysiol 2010; 104:1673-80. [PMID: 20554836 DOI: 10.1152/jn.00233.2010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Motor learning and habit formation are thought to depend on corticostriatal synaptic plasticity. Moreover, basolateral amygdala (BLA) activity facilitates consolidation of striatal-dependent memories. Accordingly, BLA stimulation in vitro facilitates long-term potentiation (LTP) induction at corticostriatal synapses onto medium spiny neurons (MSNs). Although these effects were found to depend on N-methyl-d-aspartate (NMDA) receptor activation at BLA synapses and consequent Ca(2+) influx, it is unclear how this event can facilitate LTP at cortical synapses, even when the two inputs are not coactivated. Here, we aimed to shed light on this question, using whole cell recordings of MSNs in vitro. We first tested whether BLA inputs end at more proximal dendritic sites than cortical inputs. In this scenario, BLA synapses would experience stronger spike-related depolarizations and be in a strategic position to control the spread of second messengers. However, comparison of compound excitatory postsynaptic potentials and single-axon excitatory postsynaptic currents revealed that BLA and cortical synapses are intermingled. Next, we examined the sensitivity of cortical and BLA NMDA responses to ifenprodil because NR2A-containing NMDA receptors have faster kinetics than those containing NR2B subunits. However, the two inputs did not differ in this respect. Last, reasoning that propagating waves of Ca(2+)-induced Ca(2+) release (CICR) could bridge temporal gaps between the two inputs, we tested the effects of CICR inhibitors on the BLA facilitation of corticostriatal LTP induction. Pharmacological interference with CICR blocked corticostriatal LTP induction. Thus our results are consistent with the notion that NMDA-dependent Ca(2+) influx at BLA synapses initiates propagating waves of CICR, thereby biasing active corticostriatal inputs toward synaptic potentiation.
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Affiliation(s)
- Andrei T Popescu
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ 07102, USA
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Intracellular calcium ion dynamics involved in long-term potentiation in hippocampal CA1 neurons in mice lacking the IP3 type 1 receptor. Neurosci Res 2010; 67:149-55. [DOI: 10.1016/j.neures.2010.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 02/09/2010] [Accepted: 03/03/2010] [Indexed: 11/17/2022]
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Yücel MA, Devor A, Akin A, Boas DA. The Possible Role of CO(2) in Producing A Post-Stimulus CBF and BOLD Undershoot. FRONTIERS IN NEUROENERGETICS 2009; 1:7. [PMID: 20027233 PMCID: PMC2795469 DOI: 10.3389/neuro.14.007.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 10/08/2009] [Indexed: 12/04/2022]
Abstract
Comprehending the underlying mechanisms of neurovascular coupling is important for understanding the pathogenesis of neurodegenerative diseases related to uncoupling. Moreover, it elucidates the casual relation between the neural signaling and the hemodynamic responses measured with various imaging modalities such as functional magnetic resonance imaging (fMRI). There are mainly two hypotheses concerning this mechanism: a metabolic hypothesis and a neurogenic hypothesis. We have modified recent models of neurovascular coupling adding the effects of both NO (nitric oxide) kinetics, which is a well-known neurogenic vasodilator, and CO2 kinetics as a metabolic vasodilator. We have also added the Hodgkin–Huxley equations relating the membrane potentials to sodium influx through the membrane. Our results show that the dominant factor in the hemodynamic response is NO, however CO2 is important in producing a brief post-stimulus undershoot in the blood flow response that in turn modifies the fMRI blood oxygenation level-dependent post-stimulus undershoot. Our results suggest that increased cerebral blood flow during stimulation causes CO2 washout which then results in a post-stimulus hypocapnia induced vasoconstrictive effect.
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Affiliation(s)
- Meryem A Yücel
- Institute of Biomedical Engineering, Boğaziçi University Istanbul, Turkey
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Dulla CG, Frenguelli BG, Staley KJ, Masino SA. Intracellular acidification causes adenosine release during states of hyperexcitability in the hippocampus. J Neurophysiol 2009; 102:1984-93. [PMID: 19625534 PMCID: PMC2746788 DOI: 10.1152/jn.90695.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 07/08/2009] [Indexed: 12/20/2022] Open
Abstract
Decreased pH increases extracellular adenosine in CNS regions as diverse as hippocampus and ventral medulla. However, thus far there is no clear consensus whether the critical pH change is a decrease in intracellular and/or extracellular pH. Previously we showed that a decrease in extracellular pH is necessary and a decrease in intracellular pH alone is not sufficient, to increase extracellular adenosine in an acute hippocampal slice preparation. Here we explored further the role of intracellular pH under different synaptic conditions in the hippocampal slice. When synaptic excitability was increased, either during gamma-aminobutyric acid type A receptor blockade in CA1 or after the induction of persistent bursting in CA3, a decrease in intracellular pH alone was now sufficient to: 1) elevate extracellular adenosine concentration, 2) activate adenosine A1 receptors, 3) decrease excitatory synaptic transmission (CA1), and 4) attenuate burst frequency in an in vitro seizure model (CA3). Hippocampal slices obtained from adenosine A1 receptor knockout mice did not exhibit these pH-mediated effects on synaptic transmission, further confirming the role of adenosine acting at the adenosine A1 receptor. Taken together, these data strengthen and add significantly to the evidence outlining a change in pH as an important stimulus influencing extracellular adenosine. In addition, we identify conditions under which intracellular pH plays a dominant role in regulating extracellular adenosine concentrations.
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Affiliation(s)
- Chris G Dulla
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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Deviant ryanodine receptor-mediated calcium release resets synaptic homeostasis in presymptomatic 3xTg-AD mice. J Neurosci 2009; 29:9458-70. [PMID: 19641109 DOI: 10.1523/jneurosci.2047-09.2009] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Presenilin mutations result in exaggerated endoplasmic reticulum (ER) calcium release in cellular and animal models of Alzheimer's disease (AD). In this study, we examined whether dysregulated ER calcium release in young 3xTg-AD neurons alters synaptic transmission and plasticity mechanisms before the onset of histopathology and cognitive deficits. Using electrophysiological recordings and two-photon calcium imaging in young (6-8 weeks old) 3xTg-AD and non-transgenic (NonTg) hippocampal slices, we show a marked increase in ryanodine receptor (RyR)-evoked calcium release within synapse-dense regions of CA1 pyramidal neurons. In addition, we uncovered a deviant contribution of presynaptic and postsynaptic ryanodine receptor-sensitive calcium stores to synaptic transmission and plasticity in 3xTg-AD mice that is not present in NonTg mice. As a possible underlying mechanism, the RyR2 isoform was found to be selectively increased more than fivefold in the hippocampus of 3xTg-AD mice relative to the NonTg controls. These novel findings demonstrate that 3xTg-AD CA1 neurons at presymptomatic ages operate under an aberrant, yet seemingly functional, calcium signaling and synaptic transmission system long before AD histopathology onset. These early signaling alterations may underlie the later synaptic breakdown and cognitive deficits characteristic of later stage AD.
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Metabotropic glutamate receptor-mediated LTD involves two interacting Ca(2+) sensors, NCS-1 and PICK1. Neuron 2009; 60:1095-111. [PMID: 19109914 DOI: 10.1016/j.neuron.2008.10.050] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 08/26/2008] [Accepted: 10/29/2008] [Indexed: 11/21/2022]
Abstract
There are two major forms of long-term depression (LTD) of synaptic transmission in the central nervous system that require activation of either N-methyl-D-aspartate receptors (NMDARs) or metabotropic glutamate receptors (mGluRs). In synapses in the perirhinal cortex, we have directly compared the Ca(2+) signaling mechanisms involved in NMDAR-LTD and mGluR-LTD. While both forms of LTD involve Ca(2+) release from intracellular stores, the Ca(2+) sensors involved are different; NMDAR-LTD involves calmodulin, while mGluR-LTD involves the neuronal Ca(2+) sensor (NCS) protein NCS-1. In addition, there is a specific requirement for IP3 and PKC, as well as protein interacting with C kinase (PICK-1) in mGluR-LTD. NCS-1 binds directly to PICK1 via its BAR domain in a Ca(2+)-dependent manner. Furthermore, the NCS-1-PICK1 association is stimulated by activation of mGluRs, but not NMDARs, and introduction of a PICK1 BAR domain fusion protein specifically blocks mGluR-LTD. Thus, NCS-1 plays a distinct role in mGluR-LTD.
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GLUK1 receptor antagonists and hippocampal mossy fiber function. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 85:13-27. [PMID: 19607958 DOI: 10.1016/s0074-7742(09)85002-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Kainate receptors, one of the three subtypes of ionotropic receptors for the excitatory transmitter l-glutamate, play a variety of functions in the regulation of synaptic activity. Their physiological properties and functional roles have been identified only recently, following the discovery of selective pharmacological tools that allow for isolation of kainate receptor-mediated events. A considerable amount of data indicates that this class of glutamate receptors is located both at the pre- and postsynaptic site, playing a special role in regulating transmission and controlling short- and long-term plasticity. In this review, we summarize some data obtained in our laboratory over the last decade illustrating how various ligands have contributed to our understanding of the physiological role for neuronal kainate receptors. In particular, we show that the GluK1-containing KARs are important for regulating synaptic facilitation and LTP induction at hippocampal mossy fiber synapses.
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Klejman ME, Gruszczynska-Biegala J, Skibinska-Kijek A, Wisniewska MB, Misztal K, Blazejczyk M, Bojarski L, Kuznicki J. Expression of STIM1 in brain and puncta-like co-localization of STIM1 and ORAI1 upon depletion of Ca(2+) store in neurons. Neurochem Int 2008; 54:49-55. [PMID: 19013491 DOI: 10.1016/j.neuint.2008.10.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 10/14/2008] [Accepted: 10/15/2008] [Indexed: 12/17/2022]
Abstract
Recent findings indicate that Store Operated Ca(2+) Entry (SOCE) in non-excitable cells is based on the interaction of ER calcium sensor STIM1 with the plasma membrane Ca(2+) channel protein ORAI1. However, despite physiological evidence for functional SOCE in neurons, its mechanism is not known. Using PCR, immunoblotting and immunohistochemical methods we show that STIM1 protein is present in the mouse brain. The protein and mRNA levels of STIM1 are similar in the thalamus, the hippocampus, the cortex and the amygdala and the higher level is observed in the cerebellum. Immunohistochemistry of the cortex and the hippocampus of brain sections shows that STIM1 is present in cell bodies and dendrites of pyramidal neurons. In the cerebellum STIM1 is present in Purkinje and granule cells. The same immunostaining pattern is observed in cultured hippocampal and cortical neurons. Localization of YFP-STIM1 and ORAI1 changes from a dispersed pattern in untreated cortical neurons to puncta-like pattern in cells with a Ca(2+) store depleted by thapsigargin treatment. The YFP-STIM1(D76A) dominant positive mutant, which is active regardless of the Ca(2+) level in ER, concentrates as puncta even without depletion of the neuronal Ca(2+) store. Also, this mutant forces ORAI1 redistribution to form puncta-like staining. We suggest that in neurons, just as in non-excitable cells, the STIM1 and ORAI1 proteins are involved in SOCE.
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Affiliation(s)
- Monika E Klejman
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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