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Carnovale C, Perrotta C, Baldelli S, Cattaneo D, Montrasio C, Barbieri SS, Pompilio G, Vantaggiato C, Clementi E, Pozzi M. Antihypertensive drugs and brain function: mechanisms underlying therapeutically beneficial and harmful neuropsychiatric effects. Cardiovasc Res 2022; 119:647-667. [PMID: 35895876 PMCID: PMC10153433 DOI: 10.1093/cvr/cvac110] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 06/15/2022] [Accepted: 06/21/2022] [Indexed: 11/14/2022] Open
Abstract
A bidirectional relationship exists between hypertension and psychiatric disorders, including unipolar and bipolar depression, anxiety, post-traumatic stress disorder (PTSD), psychosis, schizophrenia, mania, and dementia/cognitive decline. Repurposing of antihypertensive drugs to treat mental disorders is thus being explored. A systematic knowledge of the mechanisms of action and clinical consequences of the use of antihypertensive agents on neuropsychiatric functions has not been achieved yet. In this article, we review the putative role of antihypertensive agents in psychiatric disorders, discuss the targets and mechanisms of action, and examine how and to what extent specific drug classes/molecules may trigger, worsen, or mitigate psychiatric symptoms. In addition, we review pharmacokinetics (brain penetration of drugs) and pharmacogenetics data that add important information to assess risks and benefits of antihypertensive drugs in neuropsychiatric settings. The scientific literature shows robust evidence of a positive effect of α1 blockers on PTSD symptoms, nightmares and sleep quality, α2 agonists on core symptoms, executive function and quality of life in Attention-Deficit/Hyperactivity Disorder, PTSD, Tourette's syndrome, and β blockers on anxiety, aggression, working memory, and social communication. Renin-angiotensin system modulators exert protective effects on cognition, depression, and anxiety, and the loop diuretic bumetanide reduced the core symptoms of autism in a subset of patients. There is no evidence of clear benefits of calcium channel blockers in mood disorders in the scientific literature. These findings are mainly from preclinical studies; clinical data are still insufficient or of anecdotal nature, and seldom systematic. The information herewith provided can support a better therapeutic approach to hypertension, tailored to patients with, or with high susceptibility to, psychiatric illness. It may prompt clinical studies exploring the potential benefit of antihypertensive drugs in selected patients with neuropsychiatric comorbidities that include outcomes of neuropsychiatric interest and specifically assess undesirable effects or interactions.
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Affiliation(s)
- Carla Carnovale
- Unit of Clinical Pharmacology, Department of Biomedical and Clinical Sciences (DIBIC), ASST Fatebenefratelli-Sacco University Hospital, Università degli Studi di Milano, 20157 Milano, Italy
| | - Cristiana Perrotta
- Unit of Clinical Pharmacology, Department of Biomedical and Clinical Sciences (DIBIC), ASST Fatebenefratelli-Sacco University Hospital, Università degli Studi di Milano, 20157 Milano, Italy
| | - Sara Baldelli
- Unit of Clinical Pharmacology, ASST Fatebenefratelli-Sacco University Hospital, 20157 Milano, Italy
| | - Dario Cattaneo
- Unit of Clinical Pharmacology, ASST Fatebenefratelli-Sacco University Hospital, 20157 Milano, Italy
| | - Cristina Montrasio
- Unit of Clinical Pharmacology, ASST Fatebenefratelli-Sacco University Hospital, 20157 Milano, Italy
| | - Silvia S Barbieri
- Unit of Brain-Heart axis: cellular and molecular mechanisms - Centro Cardiologico Monzino IRCCS, 20138 Milano, Italy
| | - Giulio Pompilio
- Unit of Vascular Biology and Regenerative Medicine - Centro Cardiologico Monzino IRCCS, 20138, Milan, Italy.,Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Milan, Italy
| | | | - Emilio Clementi
- Unit of Clinical Pharmacology, Department of Biomedical and Clinical Sciences (DIBIC), ASST Fatebenefratelli-Sacco University Hospital, Università degli Studi di Milano, 20157 Milano, Italy.,Scientific Institute IRCCS Eugenio Medea, Bosisio Parini (LC), Italy
| | - Marco Pozzi
- Scientific Institute IRCCS Eugenio Medea, Bosisio Parini (LC), Italy
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2
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Hiess F, Yao J, Song Z, Sun B, Zhang Z, Huang J, Chen L, Institoris A, Estillore JP, Wang R, Ter Keurs HEDJ, Stys PK, Gordon GR, Zamponi GW, Ganguly A, Chen SRW. Subcellular localization of hippocampal ryanodine receptor 2 and its role in neuronal excitability and memory. Commun Biol 2022; 5:183. [PMID: 35233070 PMCID: PMC8888588 DOI: 10.1038/s42003-022-03124-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/01/2022] [Indexed: 11/09/2022] Open
Abstract
Ryanodine receptor 2 (RyR2) is abundantly expressed in the heart and brain. Mutations in RyR2 are associated with both cardiac arrhythmias and intellectual disability. While the mechanisms of RyR2-linked arrhythmias are well characterized, little is known about the mechanism underlying RyR2-associated intellectual disability. Here, we employed a mouse model expressing a green fluorescent protein (GFP)-tagged RyR2 and a specific GFP probe to determine the subcellular localization of RyR2 in hippocampus. GFP-RyR2 was predominantly detected in the soma and dendrites, but not the dendritic spines of CA1 pyramidal neurons or dentate gyrus granular neurons. GFP-RyR2 was also detected within the mossy fibers in the stratum lucidum of CA3, but not in the presynaptic terminals of CA1 neurons. An arrhythmogenic RyR2-R4496C+/− mutation downregulated the A-type K+ current and increased membrane excitability, but had little effect on the afterhyperpolarization current or presynaptic facilitation of CA1 neurons. The RyR2-R4496C+/− mutation also impaired hippocampal long-term potentiation, learning, and memory. These data reveal the precise subcellular distribution of hippocampal RyR2 and its important role in neuronal excitability, learning, and memory. A mouse model containing a GFP-tagged ryanodine receptor 2 (RyR2) has shed light on the precise subcellular localization of hippocampal RyR2 and mechanisms underlying neuronal excitability, learning, and memory.
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Affiliation(s)
- Florian Hiess
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Jinjing Yao
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Zhenpeng Song
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Bo Sun
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Zizhen Zhang
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Junting Huang
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Lina Chen
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Adam Institoris
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - John Paul Estillore
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Henk E D J Ter Keurs
- Libin Cardiovascular Institute, Department of Cardiovascular Science, Department of Medicine, University of Calgary, Calgary, AB, Canada
| | - Peter K Stys
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Gerald W Zamponi
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Anutosh Ganguly
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | - S R Wayne Chen
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada. .,Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada.
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3
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Chami M, Checler F. Targeting Post-Translational Remodeling of Ryanodine Receptor: A New Track for Alzheimer's Disease Therapy? Curr Alzheimer Res 2021; 17:313-323. [PMID: 32096743 DOI: 10.2174/1567205017666200225102941] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/08/2020] [Accepted: 02/24/2020] [Indexed: 01/20/2023]
Abstract
Pathologic calcium (Ca2+) signaling linked to Alzheimer's Disease (AD) involves the intracellular Ca2+ release channels/ryanodine receptors (RyRs). RyRs are macromolecular complexes where the protein-protein interactions between RyRs and several regulatory proteins impact the channel function. Pharmacological and genetic approaches link the destabilization of RyRs macromolecular complexes to several human pathologies including brain disorders. In this review, we discuss our recent data, which demonstrated that enhanced neuronal RyR2-mediated Ca2+ leak in AD is associated with posttranslational modifications (hyperphosphorylation, oxidation, and nitrosylation) leading to RyR2 macromolecular complex remodeling, and dissociation of the stabilizing protein Calstabin2 from the channel. We describe RyR macromolecular complex structure and discuss the molecular mechanisms and signaling cascade underlying neuronal RyR2 remodeling in AD. We provide evidence linking RyR2 dysfunction with β-adrenergic signaling cascade that is altered in AD. RyR2 remodeling in AD leads to histopathological lesions, alteration of synaptic plasticity, learning and memory deficits. Targeting RyR macromolecular complex remodeling should be considered as a new therapeutic window to treat/or prevent AD setting and/or progression.
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Affiliation(s)
- Mounia Chami
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, F-06560, France.,CNRS, IPMC, Sophia Antipolis, F-06560, France
| | - Frédéric Checler
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, F-06560, France.,CNRS, IPMC, Sophia Antipolis, F-06560, France
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4
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TSUBOI M, HIRABAYASHI Y. New insights into the regulation of synaptic transmission and plasticity by the endoplasmic reticulum and its membrane contacts. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:559-572. [PMID: 34897182 PMCID: PMC8687855 DOI: 10.2183/pjab.97.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 10/18/2021] [Indexed: 06/14/2023]
Abstract
Mammalian neurons are highly compartmentalized yet very large cells. To provide each compartment with its distinct properties, metabolic homeostasis and molecular composition need to be precisely coordinated in a compartment-specific manner. Despite the importance of the endoplasmic reticulum (ER) as a platform for various biochemical reactions, such as protein synthesis, protein trafficking, and intracellular calcium control, the contribution of the ER to neuronal compartment-specific functions and plasticity remains elusive. Recent advances in the development of live imaging and serial scanning electron microscopy (sSEM) analysis have revealed that the neuronal ER is a highly dynamic organelle with compartment-specific structures. sSEM studies also revealed that the ER forms contacts with other membranes, such as the mitochondria and plasma membrane, although little is known about the functions of these ER-membrane contacts. In this review, we discuss the mechanisms and physiological roles of the ER structure and ER-mitochondria contacts in synaptic transmission and plasticity, thereby highlighting a potential link between organelle ultrastructure and neuronal functions.
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Affiliation(s)
- Masafumi TSUBOI
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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5
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Mahajan G, Nadkarni S. Intracellular calcium stores mediate metaplasticity at hippocampal dendritic spines. J Physiol 2019; 597:3473-3502. [PMID: 31099020 PMCID: PMC6636706 DOI: 10.1113/jp277726] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/16/2019] [Indexed: 12/21/2022] Open
Abstract
Key points Calcium (Ca2+) entry mediated by NMDA receptors is considered central to the induction of activity‐dependent synaptic plasticity in hippocampal area CA1; this description does not, however, take into account the potential contribution of endoplasmic reticulum (ER) Ca2+ stores. The ER has a heterogeneous distribution in CA1 dendritic spines, and may introduce localized functional differences in Ca2+ signalling between synapses, as suggested by experiments on metabotropic receptor‐dependent long‐term depression. A physiologically detailed computational model of Ca2+ dynamics at a CA3–CA1 excitatory synapse characterizes the contribution of spine ER via metabotropic signalling during plasticity induction protocols. ER Ca2+ release via IP3 receptors modulates NMDA receptor‐dependent plasticity in a graded manner, to selectively promote synaptic depression with relatively diminished effect on LTP induction; this may temper further strengthening at the stronger synapses which are preferentially associated with ER‐containing spines. Acquisition of spine ER may thus represent a local, biophysically plausible ‘metaplastic switch’ at potentiated CA1 synapses, contributing to the plasticity–stability balance in neural circuits.
Abstract Long‐term plasticity mediated by NMDA receptors supports input‐specific, Hebbian forms of learning at excitatory CA3–CA1 connections in the hippocampus. There exists an additional layer of stabilizing mechanisms that act globally as well as locally over multiple time scales to ensure that plasticity occurs in a constrained manner. Here, we investigated the role of calcium (Ca2+) stores associated with the endoplasmic reticulum (ER) in the local regulation of plasticity at individual CA1 synapses. Our study was spurred by (1) the curious observation that ER is sparsely distributed in dendritic spines, but over‐represented in larger spines that are likely to have undergone activity‐dependent strengthening, and (2) evidence suggesting that ER motility at synapses can be rapid, and accompany activity‐regulated spine remodelling. We constructed a physiologically realistic computational model of an ER‐bearing CA1 spine, and examined how IP3‐sensitive Ca2+ stores affect spine Ca2+ dynamics during activity patterns mimicking the induction of long‐term potentiation and long‐term depression (LTD). Our results suggest that the presence of ER modulates NMDA receptor‐dependent plasticity in a graded manner that selectively enhances LTD induction. We propose that ER may locally tune Ca2+‐based plasticity, providing a braking mechanism to mitigate runaway strengthening at potentiated synapses. Our study provides a biophysically accurate description of postsynaptic Ca2+ regulation, and suggests that ER in the spine may promote the re‐use of hippocampal synapses with saturated strengths. Calcium (Ca2+) entry mediated by NMDA receptors is considered central to the induction of activity‐dependent synaptic plasticity in hippocampal area CA1; this description does not, however, take into account the potential contribution of endoplasmic reticulum (ER) Ca2+ stores. The ER has a heterogeneous distribution in CA1 dendritic spines, and may introduce localized functional differences in Ca2+ signalling between synapses, as suggested by experiments on metabotropic receptor‐dependent long‐term depression. A physiologically detailed computational model of Ca2+ dynamics at a CA3–CA1 excitatory synapse characterizes the contribution of spine ER via metabotropic signalling during plasticity induction protocols. ER Ca2+ release via IP3 receptors modulates NMDA receptor‐dependent plasticity in a graded manner, to selectively promote synaptic depression with relatively diminished effect on LTP induction; this may temper further strengthening at the stronger synapses which are preferentially associated with ER‐containing spines. Acquisition of spine ER may thus represent a local, biophysically plausible ‘metaplastic switch’ at potentiated CA1 synapses, contributing to the plasticity–stability balance in neural circuits.
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Affiliation(s)
- Gaurang Mahajan
- Indian Institute of Science Education and Research, Pune, 411 008, India
| | - Suhita Nadkarni
- Indian Institute of Science Education and Research, Pune, 411 008, India
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6
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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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7
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Arias-Cavieres A, Barrientos GC, Sánchez G, Elgueta C, Muñoz P, Hidalgo C. Ryanodine Receptor-Mediated Calcium Release Has a Key Role in Hippocampal LTD Induction. Front Cell Neurosci 2018; 12:403. [PMID: 30459562 PMCID: PMC6232521 DOI: 10.3389/fncel.2018.00403] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 10/18/2018] [Indexed: 01/04/2023] Open
Abstract
The induction of both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission entails pre- and postsynaptic Ca2+ signals, which represent transient increments in cytoplasmic free Ca2+ concentration. In diverse synapse types, Ca2+ release from intracellular stores contributes to amplify the Ca2+ signals initially generated by activation of neuronal Ca2+ entry pathways. Here, we used hippocampal slices from young male rats to evaluate whether pharmacological activation or inhibition of Ca2+ release from the endoplasmic reticulum (ER) mediated by ryanodine receptor (RyR) channels modifies LTD induction at Schaffer collateral-CA1 synapses. Pre-incubation of slices with ryanodine (1 μM, 1 h) or caffeine (1 mM, 30 min) to promote RyR-mediated Ca2+ release facilitated LTD induction by low frequency stimulation (LFS), but did not affect the amplitude of synaptic transmission, the profiles of field excitatory postsynaptic potentials (fEPSP) or the paired-pulse (PP) responses. Conversely, treatment with inhibitory ryanodine (20 μM, 1 h) to suppress RyR-mediated Ca2+ release prevented LTD induction, but did not affect baseline synaptic transmission or PP responses. Previous literature reports indicate that LTD induction requires presynaptic CaMKII activity. We found that 1 h after applying the LTD induction protocol, slices displayed a significant increase in CaMKII phosphorylation relative to the levels exhibited by un-stimulated (naïve) slices. In addition, LTD induction (1 h) enhanced the phosphorylation of the presynaptic protein Synapsin I at a CaMKII-dependent phosphorylation site, indicating that LTD induction stimulates presynaptic CaMKII activity. Pre-incubation of slices with 20 μM ryanodine abolished the increased CaMKII and Synapsin I phosphorylation induced by LTD, whereas naïve slices pre-incubated with inhibitory ryanodine displayed similar CaMKII and Synapsin I phosphorylation levels as naïve control slices. We posit that inhibitory ryanodine suppressed LTD-induced presynaptic CaMKII activity, as evidenced by the suppression of Synapsin I phosphorylation induced by LTD. Accordingly, we propose that presynaptic RyR-mediated Ca2+ signals contribute to LTD induction at Schaffer collateral-CA1 synapses.
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Affiliation(s)
- Alejandra Arias-Cavieres
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Genaro C Barrientos
- Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Gina Sánchez
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Pathophysiology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Claudio Elgueta
- Systemic and Cellular Neurophysiology, Physiology Institute I, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Pablo Muñoz
- Pathology and Physiology Department, Medical School, Faculty of Medicine, Universidad de Valparaíso, Valparaíso, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Department of Neuroscience and Center of Molecular Studies of the Cell, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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8
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Breit M, Kessler M, Stepniewski M, Vlachos A, Queisser G. Spine-to-Dendrite Calcium Modeling Discloses Relevance for Precise Positioning of Ryanodine Receptor-Containing Spine Endoplasmic Reticulum. Sci Rep 2018; 8:15624. [PMID: 30353066 PMCID: PMC6199256 DOI: 10.1038/s41598-018-33343-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 09/18/2018] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum (ER) forms a complex endomembrane network that reaches into the cellular compartments of a neuron, including dendritic spines. Recent work discloses that the spine ER is a dynamic structure that enters and leaves spines. While evidence exists that ER Ca2+ release is involved in synaptic plasticity, the role of spine ER morphology remains unknown. Combining a new 3D spine generator with 3D Ca2+ modeling, we addressed the relevance of ER positioning on spine-to-dendrite Ca2+ signaling. Our simulations, which account for Ca2+ exchange on the plasma membrane and ER, show that spine ER needs to be present in distinct morphological conformations in order to overcome a barrier between the spine and dendritic shaft. We demonstrate that RyR-carrying spine ER promotes spine-to-dendrite Ca2+ signals in a position-dependent manner. Our simulations indicate that RyR-carrying ER can initiate time-delayed Ca2+ reverberation, depending on the precise position of the spine ER. Upon spine growth, structural reorganization of the ER restores spine-to-dendrite Ca2+ communication, while maintaining aspects of Ca2+ homeostasis in the spine head. Our work emphasizes the relevance of precise positioning of RyR-containing spine ER in regulating the strength and timing of spine Ca2+ signaling, which could play an important role in tuning spine-to-dendrite Ca2+ communication and homeostasis.
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Affiliation(s)
- Markus Breit
- Goethe Center for Scientific Computing, Computational Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Marcus Kessler
- Goethe Center for Scientific Computing, Computational Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Martin Stepniewski
- Goethe Center for Scientific Computing, Computational Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, 79104, Germany. .,Bernstein Center Freiburg, University of Freiburg, Freiburg, 79104, Germany.
| | - Gillian Queisser
- Department of Mathematics, Temple University, Philadelphia, USA.
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Qian Z, Wu X, Qiao Y, Shi M, Liu Z, Ren W, Han J, Zheng Q. Downregulation of mGluR2/3 receptors during morphine withdrawal in rats impairs mGluR2/3- and NMDA receptor-dependent long-term depression in the nucleus accumbens. Neurosci Lett 2018; 690:76-82. [PMID: 30315852 DOI: 10.1016/j.neulet.2018.10.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 09/29/2018] [Accepted: 10/09/2018] [Indexed: 10/28/2022]
Abstract
Drugs of abuse modify synaptic long-term potentiation and long-term depression (LTD) in the nucleus accumbens, and the impairment of synaptic plasticity in this brain region may be a universal feature of drug addiction. It is unknown whether metabotropic glutamate receptors (mGluRs) play a role in synaptic plasticity induced by drugs such as morphine. The neurochemical, electrophysiological, and Western blotting experiments reported here reveal a novel form of LTD in synapses of the shell region of the nucleus accumbens induced in vivo by low-frequency stimulation of the medial prefrontal cortex. This plasticity required the activation of N-methyl-d-aspartate receptors and mGluR2/3 but not mGluR5. The expression of mGluR2/3 was downregulated during withdrawal from repeated morphine exposure (10 days after the last injection), resulting in impaired low-frequency stimulation-induced LTD. These results indicate that withdrawal-induced mGluR2/3 downregulation alters neural plasticity after morphine exposure, which may be a mechanism contributing to drug addiction.
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Affiliation(s)
- Zhaoqiang Qian
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China; College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Xiaojie Wu
- College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Yanning Qiao
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Meimei Shi
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Zhiqiang Liu
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Wei Ren
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Jing Han
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China
| | - Qiaohua Zheng
- Key Laboratory of Modern Teaching Technology, Ministry of Education, Shaanxi Normal University, Xi'an, Shaanxi, 710062, PR China.
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10
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Lacampagne A, Liu X, Reiken S, Bussiere R, Meli AC, Lauritzen I, Teich AF, Zalk R, Saint N, Arancio O, Bauer C, Duprat F, Briggs CA, Chakroborty S, Stutzmann GE, Shelanski ML, Checler F, Chami M, Marks AR. Post-translational remodeling of ryanodine receptor induces calcium leak leading to Alzheimer's disease-like pathologies and cognitive deficits. Acta Neuropathol 2017. [PMID: 28631094 DOI: 10.1007/s00401-017-1733-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanisms underlying ryanodine receptor (RyR) dysfunction associated with Alzheimer disease (AD) are still not well understood. Here, we show that neuronal RyR2 channels undergo post-translational remodeling (PKA phosphorylation, oxidation, and nitrosylation) in brains of AD patients, and in two murine models of AD (3 × Tg-AD, APP +/- /PS1 +/-). RyR2 is depleted of calstabin2 (KFBP12.6) in the channel complex, resulting in endoplasmic reticular (ER) calcium (Ca2+) leak. RyR-mediated ER Ca2+ leak activates Ca2+-dependent signaling pathways, contributing to AD pathogenesis. Pharmacological (using a novel RyR stabilizing drug Rycal) or genetic rescue of the RyR2-mediated intracellular Ca2+ leak improved synaptic plasticity, normalized behavioral and cognitive functions and reduced Aβ load. Genetically altered mice with congenitally leaky RyR2 exhibited premature and severe defects in synaptic plasticity, behavior and cognitive function. These data provide a mechanism underlying leaky RyR2 channels, which could be considered as potential AD therapeutic targets.
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11
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Kwon SK, Hirabayashi Y, Polleux F. Organelle-Specific Sensors for Monitoring Ca 2+ Dynamics in Neurons. Front Synaptic Neurosci 2016; 8:29. [PMID: 27695411 PMCID: PMC5025517 DOI: 10.3389/fnsyn.2016.00029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/30/2016] [Indexed: 11/16/2022] Open
Abstract
Calcium (Ca2+) plays innumerable critical functions in neurons ranging from regulation of neurotransmitter release and synaptic plasticity to activity-dependent transcription. Therefore, more than any other cell types, neurons are critically dependent on spatially and temporally controlled Ca2+ dynamics. This is achieved through an exquisite level of compartmentalization of Ca2+ storage and release from various organelles. The function of these organelles in the regulation of Ca2+ dynamics has been studied for decades using electrophysiological and optical methods combined with pharmacological and genetic alterations. Mitochondria and the endoplasmic reticulum (ER) are among the organelles playing the most critical roles in Ca2+ dynamics in neurons. At presynaptic boutons, Ca2+ triggers neurotransmitter release and synaptic plasticity, and postsynaptically, Ca2+ mobilization mediates long-term synaptic plasticity. To explore Ca2+ dynamics in live cells and intact animals, various synthetic and genetically encoded fluorescent Ca2+ sensors were developed, and recently, many groups actively increased the sensitivity and diversity of genetically encoded Ca2+ indicators (GECIs). Following conjugation with various signal peptides, these improved GECIs can be targeted to specific subcellular compartments, allowing monitoring of organelle-specific Ca2+ dynamics. Here, we review recent findings unraveling novel roles for mitochondria- and ER-dependent Ca2+ dynamics in neurons and at synapses.
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Affiliation(s)
- Seok-Kyu Kwon
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, Columbia University Medical Center New York, NY, USA
| | - Yusuke Hirabayashi
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, Columbia University Medical Center New York, NY, USA
| | - Franck Polleux
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, Columbia University Medical Center New York, NY, USA
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12
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Satheesh NJ, Uehara Y, Fedotova J, Pohanka M, Büsselberg D, Kruzliak P. TRPV currents and their role in the nociception and neuroplasticity. Neuropeptides 2016; 57:1-8. [PMID: 26825374 DOI: 10.1016/j.npep.2016.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 01/11/2016] [Accepted: 01/11/2016] [Indexed: 01/11/2023]
Abstract
Transient receptor potential channels sensitive to vanilloids (TRPVs) are group of ion channels which are sensitive to various tissue damaging signals and their activation is generally perceived as pain. Therefore, they are generally named as nociceptors. Understanding their activation and function as well as their interaction with intracellular pathways is crucial for the development of pharmacological interference in order to reduce pain perception. The current review summarizes basic facts in regard to TRPV and discusses their relevance in the sensing of (pain-) signals and their intracellular processing, focussing on their modulation of the intracellular calcium ([Ca(2+)]i) signal. Furthermore we discuss the basic mechanisms how the modification of [Ca(2+)]i through TRPV might induce long-term-potentiation (LTP) or long-term- depression (LTD) and from "memories" of pain. Understanding of these mechanisms is needed to localize the best point of interference for pharmacological treatment. Therefore, high attention is given to highlight physiological and pathological processes and their interaction with significant modulators and their roles in neuroplasticity and pain modulation.
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Affiliation(s)
| | - Yoshio Uehara
- Division of Clinical Nutrition, Faculty of Home Economics, Kyoritsu Women's University, Tokyo, Japan
| | - Julia Fedotova
- Laboratory of Neuroendocrinology, I.P. Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Miroslav Pohanka
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Dietrich Büsselberg
- Weill Cornell Medicine in Qatar, Qatar Foundation - Education City, Doha, Qatar
| | - Peter Kruzliak
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic; Laboratory of Structural Biology and Proteomics, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic; 2(nd) Department of Internal Medicine, Faculty of Medicine, Masaryk University, Brno, Czech Republic.
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Hidalgo C, Arias-Cavieres A. Calcium, Reactive Oxygen Species, and Synaptic Plasticity. Physiology (Bethesda) 2016; 31:201-15. [DOI: 10.1152/physiol.00038.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this review article, we address how activity-dependent Ca2+ signaling is crucial for hippocampal synaptic/structural plasticity and discuss how changes in neuronal oxidative state affect Ca2+ signaling and synaptic plasticity. We also analyze current evidence indicating that oxidative stress and abnormal Ca2+ signaling contribute to age-related synaptic plasticity deterioration.
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Affiliation(s)
- Cecilia Hidalgo
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile; and
- Center of Molecular Studies of the Cell and Physiology and Biophysics Program, ICBM, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Alejandra Arias-Cavieres
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile; and
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14
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Futagi D, Kitano K. Ryanodine-receptor-driven intracellular calcium dynamics underlying spatial association of synaptic plasticity. J Comput Neurosci 2015; 39:329-47. [PMID: 26497496 PMCID: PMC4648987 DOI: 10.1007/s10827-015-0579-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 09/24/2015] [Accepted: 09/28/2015] [Indexed: 11/28/2022]
Abstract
Synaptic modifications induced at one synapse are accompanied by hetero-synaptic changes at neighboring sites. In addition, it is suggested that the mechanism of spatial association of synaptic plasticity is based on intracellular calcium signaling that is mainly regulated by two types of receptors of endoplasmic reticulum calcium store: the ryanodine receptor (RyR) and the inositol triphosphate receptor (IP3R). However, it is not clear how these types of receptors regulate intracellular calcium flux and contribute to the outcome of calcium-dependent synaptic change. To understand the relation between the synaptic association and store-regulated calcium dynamics, we focused on the function of RyR calcium regulation and simulated its behavior by using a computational neuron model. As a result, we observed that RyR-regulated calcium release depended on spike timings of pre- and postsynaptic neurons. From the induction site of calcium release, the chain activation of RyRs occurred, and spike-like calcium increase propagated along the dendrite. For calcium signaling, the propagated calcium increase did not tend to attenuate; these characteristics came from an all-or-none behavior of RyR-sensitive calcium store. Considering the role of calcium dependent synaptic plasticity, the results suggest that RyR-regulated calcium propagation induces a similar change at the synapses. However, according to the dependence of RyR calcium regulation on the model parameters, whether the chain activation of RyRs occurred, sensitively depended on spatial expression of RyR and nominal fluctuation of calcium flux. Therefore, calcium regulation of RyR helps initiate rather than relay calcium propagation.
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Affiliation(s)
- Daiki Futagi
- Graduate School of Information Science and Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan.
| | - Katsunori Kitano
- Department of Human and Computer Intelligence, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga, 525-8577, Japan
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15
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Stein LR, Zorumski CF, Imai SI, Izumi Y. Nampt is required for long-term depression and the function of GluN2B subunit-containing NMDA receptors. Brain Res Bull 2015; 119:41-51. [PMID: 26481044 DOI: 10.1016/j.brainresbull.2015.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 09/13/2015] [Accepted: 10/12/2015] [Indexed: 01/01/2023]
Abstract
Nicotinamide adenine dinucleotide (NAD(+)) is an essential coenzyme/cosubstrate for many biological processes in cellular metabolism. The rate-limiting step in the major pathway of mammalian NAD(+) biosynthesis is mediated by nicotinamide phosphoribosyltransferase (Nampt). Previously, we showed that mice lacking Nampt in forebrain excitatory neurons (CamKIIαNampt(-/-) mice) exhibited hyperactivity, impaired learning and memory, and reduced anxiety-like behaviors. However, it remained unclear if these functional effects were accompanied by synaptic changes. Here, we show that CamKIIαNampt(-/-) mice have impaired induction of long-term depression (LTD) in the Schaffer collateral pathway, but normal induction of long-term potentiation (LTP), at postnatal day 30. Pharmacological assessments demonstrated that CamKIIαNampt(-/-) mice also display dysfunction of synaptic GluN2B (NR2B)-containing N-methyl-d-aspartate receptors (NMDARs) prior to changes in NMDAR subunit expression. These results support a novel, important role for Nampt-mediated NAD(+) biosynthesis in LTD and in the function of GluN2B-containing NMDARs.
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Affiliation(s)
- Liana Roberts Stein
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Department of Psychiatry, The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
| | - Charles F Zorumski
- Department of Psychiatry, The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Department of Anatomy and Neurobiology, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
| | - Shin-Ichiro Imai
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
| | - Yukitoshi Izumi
- Department of Psychiatry, The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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16
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Liu J, Supnet C, Sun S, Zhang H, Good L, Popugaeva E, Bezprozvanny I. The role of ryanodine receptor type 3 in a mouse model of Alzheimer disease. Channels (Austin) 2015; 8:230-42. [PMID: 24476841 PMCID: PMC4203752 DOI: 10.4161/chan.27471] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dysregulated endoplasmic reticulum (ER) calcium (Ca2+) signaling is reported to play an important role in Alzheimer disease (AD) pathogenesis. The role of ER Ca2+ release channels, the ryanodine receptors (RyanRs), has been extensively studied in AD models and RyanR expression and activity are upregulated in the brains of various familial AD (FAD) models. The objective of this study was to utilize a genetic approach to evaluate the importance of RyanR type 3 (RyanR3) in the context of AD pathology.
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17
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Adasme T, Paula-Lima A, Hidalgo C. Inhibitory ryanodine prevents ryanodine receptor-mediated Ca²⁺ release without affecting endoplasmic reticulum Ca²⁺ content in primary hippocampal neurons. Biochem Biophys Res Commun 2015; 458:57-62. [PMID: 25623539 DOI: 10.1016/j.bbrc.2015.01.065] [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] [Received: 01/12/2015] [Accepted: 01/15/2015] [Indexed: 10/24/2022]
Abstract
Ryanodine is a cell permeant plant alkaloid that binds selectively and with high affinity to ryanodine receptor (RyR) Ca(2+) release channels. Sub-micromolar ryanodine concentrations activate RyR channels while micromolar concentrations are inhibitory. Several reports indicate that neuronal synaptic plasticity, learning and memory require RyR-mediated Ca(2+)-release, which is essential for muscle contraction. The use of micromolar (inhibitory) ryanodine represents a common strategy to suppress RyR activity in neuronal cells: however, micromolar ryanodine promotes RyR-mediated Ca(2+) release and endoplasmic reticulum Ca(2+) depletion in muscle cells. Information is lacking in this regard in neuronal cells; hence, we examined here if addition of inhibitory ryanodine elicited Ca(2+) release in primary hippocampal neurons, and if prolonged incubation of primary hippocampal cultures with inhibitory ryanodine affected neuronal ER calcium content. Our results indicate that inhibitory ryanodine does not cause Ca(2+) release from the ER in primary hippocampal neurons, even though ryanodine diffusion should produce initially low intracellular concentrations, within the RyR activation range. Moreover, neurons treated for 1 h with inhibitory ryanodine had comparable Ca(2+) levels as control neurons. These combined findings imply that prolonged incubation with inhibitory ryanodine, which effectively abolishes RyR-mediated Ca(2+) release, preserves ER Ca(2+) levels and thus constitutes a sound strategy to suppress neuronal RyR function.
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Affiliation(s)
- Tatiana Adasme
- Biomedical Neuroscience Institute and Centro de Estudios Moleculares de la Célula, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrea Paula-Lima
- Biomedical Neuroscience Institute and Centro de Estudios Moleculares de la Célula, Faculty of Medicine, Universidad de Chile, Santiago, Chile; Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Biomedical Neuroscience Institute and Centro de Estudios Moleculares de la Célula, Faculty of Medicine, Universidad de Chile, Santiago, Chile; Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Chile.
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18
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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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19
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Castellano-Muñoz M, Ricci AJ. Role of intracellular calcium stores in hair-cell ribbon synapse. Front Cell Neurosci 2014; 8:162. [PMID: 24971053 PMCID: PMC4054790 DOI: 10.3389/fncel.2014.00162] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/28/2014] [Indexed: 11/13/2022] Open
Abstract
Intracellular calcium stores control many neuronal functions such as excitability, gene expression, synaptic plasticity, and synaptic release. Although the existence of calcium stores along with calcium-induced calcium release (CICR) has been demonstrated in conventional and ribbon synapses, functional significance and the cellular mechanisms underlying this role remains unclear. This review summarizes recent experimental evidence identifying contribution of CICR to synaptic transmission and synaptic plasticity in the CNS, retina and inner ear. In addition, the potential role of CICR in the recruitment of vesicles to releasable pools in hair-cell ribbon synapses will be specifically discussed.
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Affiliation(s)
| | - Anthony J Ricci
- Department of Otolaryngology, Stanford University School of Medicine Stanford, CA, USA ; Department of Molecular and Cellular Physiology, Stanford University School of Medicine Stanford, CA, USA
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20
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5HT(1B) receptor-mediated pre-synaptic depression of excitatory inputs to the rat lateral habenula. Neuropharmacology 2014; 81:153-65. [PMID: 24508708 DOI: 10.1016/j.neuropharm.2014.01.046] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 01/06/2014] [Accepted: 01/27/2014] [Indexed: 01/23/2023]
Abstract
Accumulating lines of evidence indicate that the lateral habenula (LHb), which reciprocally interacts with raphe nuclei (RN), displays hyperactivity including synaptic potentiation of excitatory inputs to the LHb during a depressed state. Despite the potential importance of glutamatergic excitatory synapses in depression-like behavior, modulation of these LHb synapses by monoamines such as serotonin (5HT) is not fully understood at the cellular and molecular level. Therefore, we used whole cell voltage-clamp recording to examine the molecular mechanisms by which 5HT modulates glutamatergic transmission in the LHb. The present study provides the first evidence that glutamatergic transmission of LHb synapses is inhibited by activation of the 5HT(1B) receptor at the pre-synapse in both acute depression (5HT-AD) and long-term depression (5HT-LTD). We further show that 5HT-AD results from the activation of Shaker-type K(+) channels whereas 5HT-LTD depends on inhibition of the adenylyl cyclase-cAMP (AC-cAMP) pathway with an increase in pre-synaptic Ca(2+) release from ryanodine-sensitive internal stores in an NO-dependent manner.
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21
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Sheng M, Ertürk A. Long-term depression: a cell biological view. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130138. [PMID: 24298141 DOI: 10.1098/rstb.2013.0138] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Recent studies of the molecular mechanisms of long-term depression (LTD) suggest a crucial role for the signalling pathways of apoptosis (programmed cell death) in the weakening and elimination of synapses and dendritic spines. With this backdrop, we suggest that LTD can be considered as the electrophysiological aspect of a larger cell biological programme of synapse involution, which uses localized apoptotic mechanisms to sculpt synapses and circuits without causing cell death.
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Affiliation(s)
- Morgan Sheng
- Department of Neuroscience, Genentech, Inc., , 1 DNA Way, South San Francisco, CA 94080, USA
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22
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Morita D, Rah JC, Isaac JTR. Incorporation of inwardly rectifying AMPA receptors at silent synapses during hippocampal long-term potentiation. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130156. [PMID: 24298157 DOI: 10.1098/rstb.2013.0156] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite decades of study, the mechanisms by which synapses express the increase in strength during long-term potentiation (LTP) remain an area of intense interest. Here, we have studied how AMPA receptor subunit composition changes during the early phases of hippocampal LTP in CA1 pyramidal neurons. We studied LTP at silent synapses that initially lack AMPA receptors, but contain NMDA receptors. We show that strongly inwardly rectifying AMPA receptors are initially incorporated at silent synapses during LTP and are then subsequently replaced by non-rectifying AMPA receptors. These findings suggest that silent synapses initially incorporate GluA2-lacking, calcium-permeable AMPA receptors during LTP that are then replaced by GluA2-containing calcium-impermeable receptors. We also show that LTP consolidation at CA1 synapses requires a rise in intracellular calcium concentration during the early phase of expression, indicating that calcium influx through the GluA2-lacking AMPA receptors drives their replacement by GluA2-containing receptors during LTP consolidation. Taken together with previous studies in hippocampus and in other brain regions, these findings suggest that a common mechanism for the expression of activity-dependent glutamatergic synaptic plasticity involves the regulation of GluA2-subunit composition and highlights a critical role for silent synapses in this process.
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Affiliation(s)
- Daiju Morita
- Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, , 35 Convent Drive, Bethesda, MD 20892, USA
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Baker KD, Edwards TM, Rickard NS. The role of intracellular calcium stores in synaptic plasticity and memory consolidation. Neurosci Biobehav Rev 2013; 37:1211-39. [PMID: 23639769 DOI: 10.1016/j.neubiorev.2013.04.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 12/20/2022]
Abstract
Memory processing requires tightly controlled signalling cascades, many of which are dependent upon intracellular calcium (Ca(2+)). Despite this, most work investigating calcium signalling in memory formation has focused on plasma membrane channels and extracellular sources of Ca(2+). The intracellular Ca(2+) release channels, ryanodine receptors (RyRs) and inositol (1,4,5)-trisphosphate receptors (IP3Rs) have a significant capacity to regulate intracellular Ca(2+) signalling. Evidence at both cellular and behavioural levels implicates both RyRs and IP3Rs in synaptic plasticity and memory formation. Pharmacobehavioural experiments using young chicks trained on a single-trial discrimination avoidance task have been particularly useful by demonstrating that RyRs and IP3Rs have distinct roles in memory formation. RyR-dependent Ca(2+) release appears to aid the consolidation of labile memory into a persistent long-term memory trace. In contrast, IP3Rs are required during long-term memory. This review discusses various functions for RyRs and IP3Rs in memory processing, including neuro- and glio-transmitter release, dendritic spine remodelling, facilitating vasodilation, and the regulation of gene transcription and dendritic excitability. Altered Ca(2+) release from intracellular stores also has significant implications for neurodegenerative conditions.
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Affiliation(s)
- Kathryn D Baker
- School of Psychology and Psychiatry, Monash University, Clayton 3800, Victoria, Australia.
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24
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Lee KJ, Queenan BN, Rozeboom AM, Bellmore R, Lim ST, Vicini S, Pak DTS. Mossy fiber-CA3 synapses mediate homeostatic plasticity in mature hippocampal neurons. Neuron 2013; 77:99-114. [PMID: 23312519 DOI: 10.1016/j.neuron.2012.10.033] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2012] [Indexed: 11/19/2022]
Abstract
Network activity homeostatically alters synaptic efficacy to constrain neuronal output. However, it is unclear how such compensatory adaptations coexist with synaptic information storage, especially in established networks. Here, we report that in mature hippocampal neurons in vitro, network activity preferentially regulated excitatory synapses within the proximal dendrites of CA3 neurons. These homeostatic synapses exhibited morphological, functional, and molecular signatures of the specialized contacts between mossy fibers of dentate granule cells and thorny excrescences (TEs) of CA3 pyramidal neurons. In vivo TEs were also selectively and bidirectionally altered by chronic activity changes. TE formation required presynaptic synaptoporin and was suppressed by the activity-inducible kinase, Plk2. These results implicate the mossy fiber-TE synapse as an independently tunable gain control locus that permits efficacious homeostatic adjustment of mossy fiber-CA3 synapses, while preserving synaptic weights that may encode information elsewhere within the mature hippocampal circuit.
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Affiliation(s)
- Kea Joo Lee
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, DC 20057, USA
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25
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Direct association of the reticulon protein RTN1A with the ryanodine receptor 2 in neurons. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1421-33. [PMID: 23454728 PMCID: PMC3636420 DOI: 10.1016/j.bbamcr.2013.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 02/11/2013] [Accepted: 02/14/2013] [Indexed: 11/21/2022]
Abstract
RTN1A is a reticulon protein with predominant localization in the endoplasmic reticulum (ER). It was previously shown that RTN1A is expressed in neurons of the mammalian central nervous system but functional information remains sparse. To elucidate the neuronal function of RTN1A, we chose to focus our investigation on identifying possible novel binding partners specifically interacting with the unique N-terminus of RTN1A. Using a nonbiased approach involving GST pull-downs and MS analysis, we identified the intracellular calcium release channel ryanodine receptor 2 (RyR2) as a direct binding partner of RTN1A. The RyR2 binding site was localized to a highly conserved 150-amino acid residue region. RTN1A displays high preference for RyR2 binding in vitro and in vivo and both proteins colocalize in hippocampal neurons and Purkinje cells. Moreover, we demonstrate the precise subcellular localization of RTN1A in Purkinje cells and show that RTN1A inhibits RyR channels in [(3)H]ryanodine binding studies on brain synaptosomes. In a functional assay, RTN1A significantly reduced RyR2-mediated Ca(2+) oscillations. Thus, RTN1A and RyR2 might act as functional partners in the regulation of cytosolic Ca(2+) dynamics the in neurons.
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26
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Ji X, Martin GE. New rules governing synaptic plasticity in core nucleus accumbens medium spiny neurons. Eur J Neurosci 2012; 36:3615-27. [PMID: 23013293 DOI: 10.1111/ejn.12002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 08/08/2012] [Accepted: 08/15/2012] [Indexed: 11/29/2022]
Abstract
The nucleus accumbens is a forebrain region responsible for drug reward and goal-directed behaviors. It has long been believed that drugs of abuse exert their addictive properties on behavior by altering the strength of synaptic communication over long periods of time. To date, attempts at understanding the relationship between drugs of abuse and synaptic plasticity have relied on the high-frequency long-term potentiation model of T.V. Bliss & T. Lømo [(1973) Journal of Physiology, 232, 331-356]. We examined synaptic plasticity using spike-timing-dependent plasticity, a stimulation paradigm that reflects more closely the in vivo firing patterns of mouse core nucleus accumbens medium spiny neurons and their afferents. In contrast to other brain regions, the same stimulation paradigm evoked bidirectional long-term plasticity. The magnitude of spike-timing-dependent long-term potentiation (tLTP) changed with the delay between action potentials and excitatory post-synaptic potentials, and frequency, whereas that of spike-timing-dependent long-term depression (tLTD) remained unchanged. We showed that tLTP depended on N-methyl-d-aspartate receptors, whereas tLTD relied on action potentials. Importantly, the intracellular calcium signaling pathways mobilised during tLTP and tLTD were different. Thus, calcium-induced calcium release underlies tLTD but not tLTP. Finally, we found that the firing pattern of a subset of medium spiny neurons was strongly inhibited by dopamine receptor agonists. Surprisingly, these neurons were exclusively associated with tLTP but not with tLTD. Taken together, these data point to the existence of two subgroups of medium spiny neurons with distinct properties, each displaying unique abilities to undergo synaptic plasticity.
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Affiliation(s)
- Xincai Ji
- Department of Psychiatry, University of Massachusetts Medical School, The Brudnick Neuropsychiatric Research Institute, 303 Belmont Street, Worcester, MA 01604, USA
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Nicolas CS, Peineau S, Amici M, Csaba Z, Fafouri A, Javalet C, Collett VJ, Hildebrandt L, Seaton G, Choi SL, Sim SE, Bradley C, Lee K, Zhuo M, Kaang BK, Gressens P, Dournaud P, Fitzjohn SM, Bortolotto ZA, Cho K, Collingridge GL. The Jak/STAT pathway is involved in synaptic plasticity. Neuron 2012; 73:374-90. [PMID: 22284190 PMCID: PMC3268861 DOI: 10.1016/j.neuron.2011.11.024] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2011] [Indexed: 12/15/2022]
Abstract
The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is involved in many cellular processes, including cell growth and differentiation, immune functions and cancer. It is activated by various cytokines, growth factors, and protein tyrosine kinases (PTKs) and regulates the transcription of many genes. Of the four JAK isoforms and seven STAT isoforms known, JAK2 and STAT3 are highly expressed in the brain where they are present in the postsynaptic density (PSD). Here, we demonstrate a new neuronal function for the JAK/STAT pathway. Using a variety of complementary approaches, we show that the JAK/STAT pathway plays an essential role in the induction of NMDA-receptor dependent long-term depression (NMDAR-LTD) in the hippocampus. Therefore, in addition to established roles in cytokine signaling, the JAK/STAT pathway is involved in synaptic plasticity in the brain.
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Affiliation(s)
- Céline S Nicolas
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
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Upreti C, Zhang XL, Alford S, Stanton PK. Role of presynaptic metabotropic glutamate receptors in the induction of long-term synaptic plasticity of vesicular release. Neuropharmacology 2012; 66:31-9. [PMID: 22626985 DOI: 10.1016/j.neuropharm.2012.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 11/24/2022]
Abstract
While postsynaptic ionotropic and metabotropic glutamate receptors have received the lions share of attention in studies of long-term activity-dependent synaptic plasticity, it is becoming clear that presynaptic metabotropic glutamate receptors play critical roles in both short-term and long-term plasticity of vesicular transmitter release, and that they act both at the level of voltage-dependent calcium channels and directly on proteins of the vesicular release machinery. Activation of G protein-coupled receptors can transiently inhibit vesicular release through the release of Gβγ which binds to both voltage-dependent calcium channels to reduce calcium influx, and directly to the C-terminus region of the SNARE protein SNAP-25. Our recent work has revealed that the binding of Gβγ to SNAP-25 is necessary, but not sufficient, to elicit long-term depression (LTD) of vesicular glutamate release, and that the concomitant release of Gα(i) and the second messenger nitric oxide are also necessary steps in the presynaptic LTD cascade. Here, we review the current state of knowledge of the molecular steps mediating short-term and long-term plasticity of vesicular release at glutamatergic synapses, and the many gaps that remain to be addressed. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Chirag Upreti
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA
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Lü N, Cheng LZ, Zhang YQ, Lü BC, Li YQ, Zhao ZQ. Involvement of ryanodine receptors in tetanic sciatic stimulation-induced long-term potentiation of spinal dorsal horn and persistent pain in rats. J Neurosci Res 2012; 90:1096-104. [PMID: 22315169 DOI: 10.1002/jnr.22799] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 08/19/2011] [Accepted: 08/22/2011] [Indexed: 01/03/2023]
Abstract
Tetanic stimulation of the sciatic nerve induces long-term potentiation (LTP) of C-fiber-evoked field potentials in the spinal dorsal horn and persistent pain, suggesting that spinal LTP may be a substrate for central sensitization of the pain pathway. However, its cellular mechanism remains unclear. The present study provides electrophysiological and behavioral evidence for the involvement of ryanodine receptor (RyR) in the induction of spinal LTP and persistent pain in rats. The specific inhibitor of ryanodine receptor, ryanodine and dantrolene, dose dependently blocked the induction, but not maintenance, of spinal LTP and reduced persistent pain behaviors induced by tetanic sciatic stimulation. Both cyclic ADP ribose (cADPR), an endogenous agonist of RyR, and (±)-1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluromethyl)-phenyl]-3-pyridine carboxylic acid methyl ester (Bay K 8644), an agonist of L-type calcium channel, attenuated ryanodine-induced inhibition. Immunohistochemistry and electron microscopic observation showed that RyR subtypes RyR1 and RyR3 were located in the spinal dorsal horn. The results suggest that RyRs are involved in synaptic plasticity of the spinal pain pathway and may be a novel target for treating pain. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Ning Lü
- Institute of Neurobiology, Institutes of Brain Science and State Key laboratory of Medical Neurobiology, Fudan University, Shanghai, China.
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Abstract
All cells use changes in intracellular calcium concentration ([Ca(2+)](i)) to regulate cell signalling events. In neurons, with their elaborate dendritic and axonal arborizations, there are clear examples of both localized and widespread Ca(2+) signals. [Ca(2+)](i) changes that are generated by Ca(2+) entry through voltage- and ligand-gated channels are the best characterized. In addition, the release of Ca(2+) from intracellular stores can result in increased [Ca(2+)](i); the signals that trigger this release have been less well-studied, in part because they are not usually associated with specific changes in membrane potential. However, recent experiments have revealed dramatic widespread Ca(2+) waves and localized spark-like events, particularly in dendrites. Here we review emerging data on the nature of these signals and their functions.
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Smith FL, LeBlanc SJ, Carter R. Influence of intracellular Ca2+ release modulating drugs on bupivacaine infiltration anesthesia in mice. Eur J Pain 2012; 8:153-61. [PMID: 14987625 DOI: 10.1016/s1090-3801(03)00089-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2003] [Accepted: 07/04/2003] [Indexed: 10/27/2022]
Abstract
The endoplasmic reticulum inside neurons can provide enormous amounts of releasable Ca2+ to increase cytosolic Ca2+ levels through the activation of endoplasmic membrane ion channels. Ryanodine (RyR) channels release Ca2+ into the cytosol when activated by Ca2+ influx through voltage-gated channels, or by cyclicADP ribose. Inositol tris-phosphate (IP3) channels are stimulated by phospolipid metabolism and the release of IP3. The hypothesis was tested that drugs that bind RyR or IP3 channels would affect the anesthetic potency of bupivacaine. The radiant heat tail-flick test was used to assess for anesthesia following subcutaneous infiltration of bupivacaine and Ca2+ modulating drugs in the tails of mice. No musculature is contained in the tail that could result in motor block. The RyR channel agonists 4-chloro-m-cresol and poly-L-lysine significantly reduced the anesthetic potency of bupivacaine. The plant alkaloid ryanodine elicited a bi-phasic effect, with low concentrations blocking bupivacaine anesthesia, and a high concentration enhancing anesthesia. Alternatively, the RyR channel antagonist dantrolene sodium dose-dependently increased bupivacaine's potency. However, the IP3 channel drugs were inactive. The IP3 agonist adenophostin A failed to affect bupivacaine anesthesia. Furthermore, bupivacaine was unaffected by the IP3 channel antagonists xestospongin C or low molecular weight heparin. Our results indicate that only the RyR channel drugs modulated the anesthetic effects of bupivacaine. Electrophysiological and molecular studies of sensory dorsal root ganglia neurons, the source of Adelta and C-fiber nociceptors, have demonstrated the presence of RyR3 Ca2+ release channels. This provides the first evidence that RyR channels might affect bupivacaine anesthesia in some fashion.
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Affiliation(s)
- Forrest L Smith
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus of Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298-0613, USA.
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Manita S, Miyazaki K, Ross WN. Synaptically activated Ca2+ waves and NMDA spikes locally suppress voltage-dependent Ca2+ signalling in rat pyramidal cell dendrites. J Physiol 2011; 589:4903-20. [PMID: 21844002 DOI: 10.1113/jphysiol.2011.216564] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Postsynaptic [Ca(2+)](i) changes contribute to several kinds of plasticity in pyramidal neurons. We examined the effects of synaptically activated Ca(2+) waves and NMDA spikes on subsequent Ca(2+) signalling in CA1 pyramidal cell dendrites in hippocampal slices. Tetanic synaptic stimulation evoked a localized Ca(2+) wave in the primary apical dendrites. The [Ca(2+)](i) increase from a backpropagating action potential (bAP) or subthreshold depolarization was reduced if it was generated immediately after the wave. The suppression had a recovery time of 30-60 s. The suppression only occurred where the wave was generated and was not due to a change in bAP amplitude or shape. The suppression also could be generated by Ca(2+) waves evoked by uncaging IP(3), showing that other signalling pathways activated by the synaptic tetanus were not required. The suppression was proportional to the amplitude of the [Ca(2+)](i) change of the Ca(2+) wave and was not blocked by a spectrum of kinase or phosphatase inhibitors, consistent with suppression due to Ca(2+)-dependent inactivation of Ca(2+) channels. The waves also reduced the frequency and amplitude of spontaneous, localized Ca(2+) release events in the dendrites by a different mechanism, probably by depleting the stores at the site of wave generation. The same synaptic tetanus often evoked NMDA spike-mediated [Ca(2+)](i) increases in the oblique dendrites where Ca(2+) waves do not propagate. These NMDA spikes suppressed the [Ca(2+)](i) increase caused by bAPs in those regions. [Ca(2+)](i) increases by Ca(2+) entry through voltage-gated Ca(2+) channels also suppressed the [Ca(2+)](i) increases from subsequent bAPs in regions where the voltage-gated [Ca(2+)](i) increases were largest, showing that all ways of raising [Ca(2+)](i) could cause suppression.
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Affiliation(s)
- Satoshi Manita
- Department of Physiology, New York Medical College, Valhalla, NY 10595, USA
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Gβγ and the C terminus of SNAP-25 are necessary for long-term depression of transmitter release. PLoS One 2011; 6:e20500. [PMID: 21633701 PMCID: PMC3102109 DOI: 10.1371/journal.pone.0020500] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 05/04/2011] [Indexed: 11/19/2022] Open
Abstract
Background Short-term presynaptic inhibition mediated by G protein-coupled receptors involves a direct interaction between G proteins and the vesicle release machinery. Recent studies implicate the C terminus of the vesicle-associated protein SNAP-25 as a molecular binding target of Gβγ that transiently reduces vesicular release. However, it is not known whether SNAP-25 is a target for molecular modifications expressing long-term changes in transmitter release probability. Methodology/Principal Findings This study utilized two-photon laser scanning microscopy for real-time imaging of action potential-evoked [Ca2+] increases, in single Schaffer collateral presynaptic release sites in in vitro hippocampal slices, plus simultaneous recording of Schaffer collateral-evoked synaptic potentials. We used electroporation to infuse small peptides through CA3 cell bodies into presynaptic Schaffer collateral terminals to selectively study the presynaptic effect of scavenging the G-protein Gβγ. We demonstrate here that the C terminus of SNAP-25 is necessary for expression of LTD, but not long-term potentiation (LTP), of synaptic strength. Using type A botulinum toxin (BoNT/A) to enzymatically cleave the 9 amino acid C-terminus of SNAP-25 eliminated the ability of low frequency synaptic stimulation to induce LTD, but not LTP, even if release probability was restored to pre-BoNT/A levels by elevating extracellular [Ca2+]. Presynaptic electroporation infusion of the 14-amino acid C-terminus of SNAP-25 (Ct-SNAP-25), to scavenge Gβγ, reduced both the transient presynaptic inhibition produced by the group II metabotropic glutamate receptor stimulation, and LTD. Furthermore, presynaptic infusion of mSIRK, a second, structurally distinct Gβγ scavenging peptide, also blocked the induction of LTD. While Gβγ binds directly to and inhibit voltage-dependent Ca2+ channels, imaging of presynaptic [Ca2+] with Mg-Green revealed that low-frequency stimulation only transiently reduced presynaptic Ca2+ influx, an effect not altered by infusion of Ct-SNAP-25. Conclusions/Significance The C-terminus of SNAP-25, which links synaptotagmin I to the SNARE complex, is a binding target for Gβγ necessary for both transient transmitter-mediated presynaptic inhibition, and the induction of presynaptic LTD.
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Ng AN, Toresson H. Endoplasmic reticulum dynamics in hippocampal dendritic spines induced by agonists of type I metabotropic glutamate but not by muscarinic acetylcholine receptors. Synapse 2011; 65:351-5. [PMID: 21284010 DOI: 10.1002/syn.20887] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 11/15/2010] [Indexed: 11/06/2022]
Abstract
Neurons in the hippocampus exhibit subpopulations of dendritic spines that contain endoplasmic reticulum (ER). ER in spines is important for synaptic activity and its associated Ca(2+) signaling. The dynamic distribution of ER to spines is regulated by diacylglycerol and partly mediated by protein kinase C, metalloproteinases and γ-secretase. In this study, we explored whether pharmacological activation of type I metabotropic glutamate receptors (mGluRs) and muscarinic acetylcholine receptors (mAChRs) known to activate phospholipase C would have any effect on spine ER content. We found that DHPG (100 μM) but not carbachol (10 μM) caused a reduction in the number of spines with ER. We further found that ER Ca(2+) depletion triggered by thapsigargin (200 nM) had no effect on ER localization in spines.
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Affiliation(s)
- Ai Na Ng
- Department of Clinical Sciences Lund, Laboratory for Experimental Brain Research, Wallenberg Neuroscience Centre, Lund University, BMC A13, 221 84 Lund, Sweden.
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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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Nani F, Cifra A, Nistri A. Transient oxidative stress evokes early changes in the functional properties of neonatal rat hypoglossal motoneurons in vitro. Eur J Neurosci 2010; 31:951-66. [PMID: 20214680 DOI: 10.1111/j.1460-9568.2010.07108.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Oxidative stress of motoneurons is believed to be an important contributor to neurodegeneration underlying the familial (and perhaps even the sporadic) form of amyotrophic lateral sclerosis (ALS). This concept has generated numerous rodent genetic models with inborn oxidative stress to mimic the clinical condition. ALS is, however, a predominantly sporadic disorder probably triggered by environmental causes. Thus, it is interesting to understand how wild-type motoneurons react to strong oxidative stress as this response might cast light on the presymptomatic disease stage. The present study used, as a model, hypoglossal motoneurons from the rat brainstem slice to investigate how hydrogen peroxide could affect synaptic transmission and intrinsic motoneuron excitability in relation to their survival. Hydrogen peroxide (1 mm; 30 min) induced inward current or membrane depolarization accompanied by an increase in input resistance, enhanced firing and depressed spontaneous synaptic events. Despite enhanced intracellular oxidative processes, there was no death of motoneurons, although most cells were immunopositive for activating transcription factor 3, a stress-related transcription factor. Voltage-clamp experiments indicated increased frequency of excitatory or inhibitory miniature events, and reduced voltage-gated persistent currents of motoneurons. The global effect of this transient oxidative challenge was to depress the input flow from the premotor interneurons to motoneurons that became more excitable due to a combination of enhanced input resistance and impaired spike afterhyperpolarization. Our data show previously unreported changes in motoneuron activity associated with cell distress caused by a transient oxidative insult.
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Affiliation(s)
- Francesca Nani
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 2-4, 34151 Trieste, Italy
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Scullin CS, Partridge LD. Contributions of SERCA pump and ryanodine-sensitive stores to presynaptic residual Ca2+. Cell Calcium 2010; 47:326-38. [PMID: 20153896 DOI: 10.1016/j.ceca.2010.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 12/31/2009] [Accepted: 01/20/2010] [Indexed: 11/24/2022]
Abstract
The presynaptic Ca2+ signal, which triggers vesicle release, disperses to a broadly distributed residual [Ca2+] ([Ca2+](res)) that plays an important role in synaptic plasticity. We have previously reported a slowing in the decay timecourse of [Ca2+](res) during the second of paired pulses. In this study, we investigated the contributions of organelle and plasma membrane Ca2+ flux pathways to the reduction of effectiveness of [Ca2+](res) clearance during short-term plasticity in Schaffer collateral terminals in the CA1 field of the hippocampus. We show that the slowed decay timecourse is mainly the result of a transport-dependent Ca2+ clearance process; that presynaptic caffeine-sensitive Ca2+ stores are not functionally loaded in the unstimulated terminal, but that these stores can effectively take up Ca2+ even during high frequency trains of stimuli; and that a rate limiting step of sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) kinetics following the first pulse is responsible for a large portion of the observed slowing of [Ca2+](res) clearance during the second pulse. We were able to accurately fit our [Ca2+](res) data with a kinetic model based on these observations and this model predicted a reduction in availability of unbound SERCA during paired pulses, but no saturation of Ca2+ buffer in the endoplasmic reticulum.
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Affiliation(s)
- Chessa S Scullin
- Department of Neurosciences, University of New Mexico, School of Medicine, Albuquerque, NM 87131, USA
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Differential distribution of endoplasmic reticulum controls metabotropic signaling and plasticity at hippocampal synapses. Proc Natl Acad Sci U S A 2009; 106:15055-60. [PMID: 19706463 DOI: 10.1073/pnas.0905110106] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synaptic plasticity is considered essential for learning and storage of new memories. Whether all synapses on a given neuron have the same ability to express long-term plasticity is not well understood. Synaptic microanatomy could affect the function of local signaling cascades and thus differentially regulate the potential for plasticity at individual synapses. Here, we investigate how the presence of endoplasmic reticulum (ER) in dendritic spines of CA1 pyramidal neurons affects postsynaptic signaling. We show that the ER is targeted selectively to large spines containing strong synapses. In ER-containing spines, we frequently observed synaptically triggered calcium release events of very large amplitudes. Low-frequency stimulation of these spines induced a permanent depression of synaptic potency that was independent of NMDA receptor activation and specific to the stimulated synapses. In contrast, no functional changes were induced in the majority of spines lacking ER. Both calcium release events and long-term depression depended on the activation of metabotropic glutamate receptors and inositol trisphosphate receptors. In summary, spine microanatomy is a reliable indicator for the presence of specific signaling cascades that govern plasticity on a micrometer scale.
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A systematic investigation of the protein kinases involved in NMDA receptor-dependent LTD: evidence for a role of GSK-3 but not other serine/threonine kinases. Mol Brain 2009; 2:22. [PMID: 19583853 PMCID: PMC2715398 DOI: 10.1186/1756-6606-2-22] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 07/07/2009] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The signalling mechanisms involved in the induction of N-methyl-D-aspartate (NMDA) receptor-dependent long-term depression (LTD) in the hippocampus are poorly understood. Numerous studies have presented evidence both for and against a variety of second messengers systems being involved in LTD induction. Here we provide the first systematic investigation of the involvement of serine/threonine (ser/thr) protein kinases in NMDAR-LTD, using whole-cell recordings from CA1 pyramidal neurons. RESULTS Using a panel of 23 inhibitors individually loaded into the recorded neurons, we can discount the involvement of at least 57 kinases, including PKA, PKC, CaMKII, p38 MAPK and DYRK1A. However, we have been able to confirm a role for the ser/thr protein kinase, glycogen synthase kinase 3 (GSK-3). CONCLUSION The present study is the first to investigate the role of 58 ser/thr protein kinases in LTD in the same study. Of these 58 protein kinases, we have found evidence for the involvement of only one, GSK-3, in LTD.
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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: 85] [Impact Index Per Article: 5.7] [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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The role of dietary niacin intake and the adenosine-5'-diphosphate-ribosyl cyclase enzyme CD38 in spatial learning ability: is cyclic adenosine diphosphate ribose the link between diet and behaviour? Nutr Res Rev 2009; 21:42-55. [PMID: 19079853 DOI: 10.1017/s0954422408945182] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The pyridine nucleotide NAD+ is derived from dietary niacin and serves as the substrate for the synthesis of cyclic ADP-ribose (cADPR), an intracellular Ca signalling molecule that plays an important role in synaptic plasticity in the hippocampus, a region of the brain involved in spatial learning. cADPR is formed in part via the activity of the ADP-ribosyl cyclase enzyme CD38, which is widespread throughout the brain. In the present review, current evidence of the relationship between dietary niacin and behaviour is presented following investigations of the effect of niacin deficiency, pharmacological nicotinamide supplementation and CD38 gene deletion on brain nucleotides and spatial learning ability in mice and rats. In young male rats, both niacin deficiency and nicotinamide supplementation significantly altered brain NAD+ and cADPR, both of which were inversely correlated with spatial learning ability. These results were consistent across three different models of niacin deficiency (pair feeding, partially restricted feeding and niacin recovery). Similar changes in spatial learning ability were observed in Cd38- / - mice, which also showed decreases in brain cADPR. These findings suggest an inverse relationship between spatial learning ability, dietary niacin intake and cADPR, although a direct link between cADPR and spatial learning ability is still missing. Dietary niacin may therefore play a role in the molecular events regulating learning performance, and further investigations of niacin intake, CD38 and cADPR may help identify potential molecular targets for clinical intervention to enhance learning and prevent or reverse cognitive decline.
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Abstract
The second messenger cyclic guanosine 3',5'-monophosphate (cGMP) plays a crucial role in the control of cardiovascular and gastrointestinal homeostastis, but its effects on neuronal functions are less established. This review summarizes recent biochemical and functional data on the role of the cGMP signalling pathway in the mammalian brain, with a focus on the regulation of synaptic plasticity, learning, and other complex behaviours. Expression profiling, along with pharmacological and genetic manipulations, indicates important functions of nitric oxide (NO)-sensitive soluble guanylyl cyclases (sGCs), cGMP-dependent protein kinases (cGKs), and cGMP-regulated phosphodiesterases (PDEs) as generators, effectors, and modulators of cGMP signals in the brain, respectively. In addition, neuronal cGMP signalling can be transmitted through cyclic nucleotide-gated (CNG) or hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels. The canonical NO/sGC/cGMP/cGK pathway modulates long-term changes of synaptic activity in the hippocampus, amygdala, cerebellum, and other brain regions, and contributes to distinct forms of learning and memory, such as fear conditioning, motor adaptation, and object recognition. Behavioural studies indicate that cGMP signalling is also involved in anxiety, addiction, and the pathogenesis of depression and schizophrenia. At the molecular level, different cGK isoforms appear to mediate effects of cGMP on presynaptic transmitter release and postsynaptic functions. The cGKs have been suggested to modulate cytoskeletal organization, vesicle and AMPA receptor trafficking, and gene expression via phosphorylation of various substrates including VASP, RhoA, RGS2, hSERT, GluR1, G-substrate, and DARPP-32. These and other components of the cGMP signalling cascade may be attractive new targets for the treatment of cognitive impairment, drug abuse, and psychiatric disorders.
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Cavazzini M, Bliss T, Emptage N. Ca2+ and synaptic plasticity. Cell Calcium 2008; 38:355-67. [PMID: 16154476 DOI: 10.1016/j.ceca.2005.06.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 11/26/2022]
Abstract
The induction and maintenance of synaptic plasticity is well established to be a Ca2+-dependent process. The use of fluorescent imaging to monitor changes [Ca2+]i in neurones has revealed a diverse array of signaling patterns across the different compartments of the cell. The Ca2+ signals within these compartments are generated by voltage or ligand-gated Ca2+ influx, and release from intracellular stores. The changes in [Ca2+]i are directly linked to the activity of the neurone, thus a neurone's input and output is translated into a dynamic Ca2+ code. Despite considerable progress in measuring this code much still remains to be determined in order to understand how the code is interpreted by the Ca2+ sensors that underlie the induction of compartment-specific plastic changes.
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Affiliation(s)
- Michele Cavazzini
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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Inhibition of mGluR1 and IP3Rs impairs long-term memory formation in young chicks. Neurobiol Learn Mem 2008; 90:269-74. [PMID: 18495503 DOI: 10.1016/j.nlm.2008.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2007] [Revised: 04/05/2008] [Accepted: 04/07/2008] [Indexed: 11/21/2022]
Abstract
Calcium (Ca(2+)) is involved in a myriad of cellular functions in the brain including synaptic plasticity. However, the role of intracellular Ca(2+) stores in memory processing remains poorly defined. The current study explored a role for glutamate-dependent intracellular Ca(2+) release in memory processing via blockade of metabotropic glutamate receptor subtype 1 (mGluR1) and inositol (1,4,5)-trisphosphate receptors (IP(3)Rs). Using a single-trial discrimination avoidance task developed for the young chick, administration of the specific and potent mGluR1 antagonist JNJ16259685 (500nM, immediately post-training, ic), or the IP(3)R antagonist Xestospongin C (5microM, immediately post-training, ic), impaired retention from 90min post-training. These findings are consistent with mGluR1 activating IP(3)Rs to release intracellular Ca(2+) required for long-term memory formation and have been interpreted within an LTP2 model. The consequences of different patterns of retention loss following ryanodine receptor (RyR) and IP(3)R inhibition are discussed.
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Geiger JE, Magoski NS. Ca2+-induced Ca2+ release in Aplysia bag cell neurons requires interaction between mitochondrial and endoplasmic reticulum stores. J Neurophysiol 2008; 100:24-37. [PMID: 18463180 DOI: 10.1152/jn.90356.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intracellular Ca2+ is influenced by both Ca2+ influx and release. We examined intracellular Ca2+ following action potential firing in the bag cell neurons of Aplysia californica. Following brief synaptic input, these neuroendocrine cells undergo an afterdischarge, resulting in elevated Ca2+ and the secretion of neuropeptides to initiate reproduction. Cultured bag cell neurons were injected with the Ca2+ indicator, fura-PE3, and subjected to simultaneous imaging and electrophysiology. Delivery of a 5-Hz, 1-min train of action potentials (mimicking the fast phase of the afterdischarge) produced a Ca2+ rise that markedly outlasted the initial influx, consistent with Ca2+-induced Ca2+ release (CICR). This response was attenuated by about half with ryanodine or depletion of the endoplasmic reticulum (ER) by cyclopiazonic acid. However, depletion of the mitochondria, with carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone, essentially eliminated CICR. Dual depletion of the ER and mitochondria did not reduce CICR further than depletion of the mitochondria alone. Moreover, tetraphenylphosphonium, a blocker of mitochondrial Ca2+ release, largely prevented CICR. The Ca2+ elevation during and subsequent to a stimulus mimicking the full afterdischarge was prominent and enhanced by protein kinase C activation. Traditionally, the ER is seen as the primary Ca2+ source for CICR. However, bag cell neuron CICR represents a departure from this view in that it relies on store interaction, where Ca2+ released from the mitochondria may in turn liberate Ca2+ from the ER. This unique form of CICR may be used by both bag cell neurons, and other neurons, to initiate secretion, activate channels, or induce gene expression.
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Affiliation(s)
- Julia E Geiger
- Department of Physiology, Queen's University, Kingston, Ontario, Canada
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Galpha(i2) inhibition of adenylate cyclase regulates presynaptic activity and unmasks cGMP-dependent long-term depression at Schaffer collateral-CA1 hippocampal synapses. Learn Mem 2008; 15:261-70. [PMID: 18391187 DOI: 10.1101/lm.810208] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cyclic AMP signaling plays a central role in regulating activity at a number of synapses in the brain. We showed previously that pairing activation of receptors that inhibit adenylate cyclase (AC) and reduce the concentration of cyclic AMP, with elevation of the concentration of cyclic GMP is sufficient to elicit a presynaptically expressed form of LTD at Schaffer collateral-CA1 synapses in the hippocampus. To directly test the role of AC inhibition and G-protein signaling in LTD at these synapses, we utilized transgenic mice that express a mutant, constitutively active inhibitory G protein, Galpha(i2), in principal neurons of the forebrain. Transgene expression of Galpha(i2) markedly enhanced LTD and impaired late-phase LTP at Schaffer collateral synapses, with no associated differences in input/output relations, paired-pulse facilitation, or NMDA receptor-gated conductances. When paired with application of a type V phosphodiesterase inhibitor to elevate the concentration of intracellular cyclic GMP, constitutively active Galpha(i2) expression converted the transient depression normally caused by this treatment to an LTD that persisted after the drug was washed out. Moreover, this effect could be mimicked in control slices by pairing type V phosphodiesterase inhibitor application with application of a PKA inhibitor. Electrophysiological recordings of spontaneous excitatory postsynaptic currents and two-photon visualization of vesicular release using FM1-43 revealed that constitutively active Galpha(i2) tonically reduced basal release probability from the rapidly recycling vesicle pool of Schaffer collateral terminals. Our findings support the hypothesis that inhibitory G-protein signaling acts presynaptically to regulate release, and, when paired with elevations in the concentration of cyclic GMP, converts a transient cyclic GMP-induced depression into a long-lasting decrease in release.
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Abstract
Nitric oxide (NO) is a multifunctional messenger in the CNS that can signal both in antero- and retrograde directions across synapses. Many effects of NO are mediated through its canonical receptor, the soluble guanylyl cyclase, and the second messenger cyclic guanosine-3',5'-monophosphate (cGMP). An increase of cGMP can also arise independently of NO via activation of membrane-bound particulate guanylyl cyclases by natriuretic peptides. The classical targets of cGMP are cGMP-dependent protein kinases (cGKs), cyclic nucleotide hydrolysing phosphodiesterases, and cyclic nucleotide-gated (CNG) cation channels. The NO/cGMP/cGK signalling cascade has been linked to the modulation of transmitter release and synaptic plasticity by numerous pharmacological and genetic studies. This review focuses on the role of NO as a retrograde messenger in long-term potentiation of transmitter release in the hippocampus. Presynaptic mechanisms of NO/cGMP/cGK signalling will be discussed with recently identified potential downstream components such as CaMKII, the vasodilator-stimulated phosphoprotein, and regulators of G protein signalling. NO has further been suggested to increase transmitter release through presynaptic clustering of a-synuclein. Alternative modes of NO/cGMP signalling resulting in inhibition of transmitter release and long-term depression of synaptic activity will also be addressed, as well as anterograde NO signalling in the cerebellum. Finally, emerging evidence for cGMP signalling through CNG channels and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels will be discussed.
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MacGregor DG, Mallon AP, Harvey AL, Young L, Nimmo HG, Stone TW. Group S8A serine proteases, including a novel enzyme cadeprin, induce long-lasting, metabotropic glutamate receptor-dependent synaptic depression in rat hippocampal slices. Eur J Neurosci 2008; 26:1870-80. [PMID: 17897396 DOI: 10.1111/j.1460-9568.2007.05808.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Long-term potentiation and long-term depression (LTD) are forms of synaptic plasticity in the central nervous system. We now report that a group of chymotrypsin-like serine proteases, especially members of the S8A subfamily, induce LTD of evoked potentials in rat hippocampal slices. The proteolytic activity of these enzymes is required for the induction of LTD, as serine protease inhibitors prevent the effect. The depression is partly mediated by the suppression of transmitter release from glutamatergic terminals but also involves an elevation of action potential threshold with no change of post-synaptic membrane potential or input resistance. We have also isolated a novel and more potent related enzyme, cadeprin, from Aspergillus. The LTD produced by all of these proteases is not dependent on receptors for several transmitter systems, including N-methyl-d-aspartate or adenosine receptors, but is prevented by blocking group I metabotropic glutamate receptors. The activity of cadeprin, subtilisin and other S8A serine proteases may shed light on the mechanisms of LTD and a related endogenous molecule could have a physiological or pathological role as a modulator of synaptic plasticity in the mammalian hippocampus.
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Affiliation(s)
- Duncan G MacGregor
- Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Scotland, UK
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Kim S, Yun HM, Baik JH, Chung KC, Nah SY, Rhim H. Functional interaction of neuronal Cav1.3 L-type calcium channel with ryanodine receptor type 2 in the rat hippocampus. J Biol Chem 2007; 282:32877-89. [PMID: 17823125 DOI: 10.1074/jbc.m701418200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal L-type Ca(2+) channels do not support synaptic transmission, but they play an essential role in synaptic activity-dependent gene expression. Ca(v)1.2 and Ca(v)1.3 are the two most widely expressed L-type Ca(2+) channels in neurons and have different biophysical and subcellular distributions. The function of the Ca(v) 1.3 L-type Ca(2+) channel and its cellular mechanisms in the central nervous system are poorly understood. In this study, using a yeast two-hybrid assay, we found that the N terminus of the rat Ca(v)1.3 alpha(1) subunit interacts with a partial N-terminal amino acid sequence of ryanodine receptor type 2 (RyR2). Reverse transcription-PCR and Western blot assays revealed high expression of both Ca(v)1.3 and RyR2 in the rat hippocampus. We also demonstrate a physical association of Ca(v)1.3 with RyR2 using co-immunoprecipitation assays. Moreover, immunocytochemistry revealed prominent co-localization between Ca(v)1.3 and RyR2 in hippocampal neurons. Depolarizing cells by an acute treatment of a high concentration of KCl (high-K, 60 mm) showed that the activation of L-type Ca(2+) channels induced RyR opening and led to RyR-dependent Ca(2+) release, even in the absence of extracellular Ca(2+). Furthermore, we found that RyR2 mRNA itself is increased by long term treatment of high-K via activation of L-type Ca(2+) channels. These acute and long term effects of high-K on RyRs were selectively blocked by small interfering RNA-mediated silencing of Ca(v)1.3. These results suggest a physical and functional interaction between Ca(v)1.3 and RyR2 and important implications of Ca(v)1.3/RyR2 clusters in translating synaptic activity into alterations in gene expression.
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Affiliation(s)
- Sunoh Kim
- Life Sciences Division, Korea Institute of Science and Technology, 39-1 Hawholgok-dong, Sungbuk-gu, Seoul, Korea
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Suzuki D, Hori T, Saitoh N, Takahashi T. 4-Chloro-m-cresol, an activator of ryanodine receptors, inhibits voltage-gated K(+) channels at the rat calyx of Held. Eur J Neurosci 2007; 26:1530-6. [PMID: 17714495 DOI: 10.1111/j.1460-9568.2007.05762.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
4-Chloro-m-cresol (4-CmC) is thought to be a specific activator of ryanodine receptors (RyRs). Using this compound, we examined whether the RyR-mediated Ca(2+) release is involved in transmitter release at the rat calyx of Held synapse in brainstem slices. Bath application of 4-CmC caused a dramatic increase in the amplitude of excitatory postsynaptic currents (TIFCs) with the half-maximal effective concentration of 0.12 mm. By making direct patch-clamp whole-cell recordings from presynaptic terminals, we investigated the mechanism by which 4-CmC facilitates transmitter release. 4-CmC markedly prolonged the duration of action potentials, with little effect on their rise time kinetics. In voltage-clamp recordings, 4-CmC inhibited voltage-gated presynaptic K(+) currents (I(pK)) by 53% (at +20 mV) but had no effect on voltage-gated presynaptic Ca(2+) currents (I(pCa)). In simultaneous pre- and postsynaptic recordings, 4-CmC had no effect on the TIFC evoked by I(pCa). Although immunocytochemical study of the calyceal terminals showed immunoreactivity to type 3 RyRs, ryanodine (0.02 mm) had no effect on the 4-CmC-induced TIFC potentiation. We conclude that the facilitatory effect of 4-CmC on nerve-evoked transmitter release is mediated by its inhibitory effect on I(pK).
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Affiliation(s)
- Daisuke Suzuki
- Department of Neurophysiology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
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