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Li S, He Y, Turner D, Wei N, Ma L, Taylor DH, Taylor DT, Ji X, Wu J. Electrophysiological Phenotypes of Hippocampal Synaptic and Network Functions in Cannabinoid Receptor 2 Knockout Mice. Cannabis Cannabinoid Res 2024. [PMID: 38502778 DOI: 10.1089/can.2023.0186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024] Open
Abstract
Background: The cannabinoid receptor 2 (CB2R), a cannabinoid receptor primarily expressed in immune cells, has been found in the brain, particularly in the hippocampus, where it plays crucial roles in modulating various neural functions, including synaptic plasticity, neuroprotection, neurogenesis, anxiety and stress responses, and neuroinflammation. Despite this growing understanding, the intricate electrophysiological characteristics of hippocampal neurons in CB2R knockout (CB2R KO) mice remain elusive. Aim and Methods: This study aimed to comprehensively assess the electrophysiological traits of hippocampal synaptic and network functions in CB2R KO mice. The focus was on aspects such as synaptic transmission, short- and long-term synaptic plasticity, and neural network synchrony (theta oscillations). Results: Our findings unveiled multiple functional traits in these CB2R KO mice, notably elevated synaptic transmission in hippocampal CA1 neurons, decreased both synaptic short-term plasticity (paired-pulse facilitation) and long-term potentiation (LTP), and impaired neural network synchronization. Conclusion: In essence, this study yields insightful revelations about the influence of CB2Rs on hippocampal neural functions. By illuminating the electrophysiological modifications in CB2R KO mice, our research enriches the comprehension of CB2R involvement in hippocampal function. Such insights could hold implications for advancing our understanding of the neural mechanisms under the influence of CB2Rs within the brain.
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Affiliation(s)
- Shuangtao Li
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
| | - Yongchang He
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Dharshaun Turner
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Naili Wei
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Luyao Ma
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Devin H Taylor
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
- Department of Biology, Utah Valley University, Orem, Utah, USA
| | | | - Xiaoyu Ji
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Jie Wu
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
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Müller NIC, Paulußen I, Hofmann LN, Fisch JO, Singh A, Friauf E. Development of synaptic fidelity and action potential robustness at an inhibitory sound localization circuit: effects of otoferlin-related deafness. J Physiol 2022; 600:2461-2497. [PMID: 35439328 DOI: 10.1113/jp280403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 03/30/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Inhibitory glycinergic inputs from the medial nucleus of the trapezoid body (MNTB) to the lateral superior olive (LSO) are involved in sound localization. This brainstem circuit performs reliably throughout life. How such reliability develops is unknown. Here we investigated the role of acoustic experience on the functional maturation of MNTB-LSO inputs at juvenile (postnatal day P11) and young-adult ages (P38) employing deaf mice lacking otoferlin (KO). We analyzed neurotransmission at single MNTB-LSO fibers in acute brainstem slices employing prolonged high-frequency stimulation (1-200 Hz|60 s). At P11, KO inputs still performed normally, as manifested by normal synaptic attenuation, fidelity, replenishment rate, temporal precision, and action potential robustness. Between P11-P38, several synaptic parameters increased substantially in WTs, collectively resulting in high-fidelity and temporally precise neurotransmission. In contrast, maturation of synaptic fidelity was largely absent in KOs after P11. Collectively, reliable neurotransmission at inhibitory MNTB-LSO inputs develops under the guidance of acoustic experience. ABSTRACT Sound localization involves information analysis in the lateral superior olive (LSO), a conspicuous nucleus in the mammalian auditory brainstem. LSO neurons weigh interaural level differences (ILDs) through precise integration of glutamatergic excitation from the cochlear nucleus (CN) and glycinergic inhibition from the medial nucleus of the trapezoid body (MNTB). Sound sources can be localized even during sustained perception, an accomplishment that requires robust neurotransmission. Virtually nothing is known about the sustained performance and the temporal precision of MNTB-LSO inputs after postnatal day (P)12 (time of hearing onset) and whether acoustic experience guides development. Here we performed whole-cell patch-clamp recordings to investigate neurotransmission of single MNTB-LSO fibers upon sustained electrical stimulation (1-200 Hz|60 s) at P11 and P38 in wild-type (WT) and deaf otoferlin (Otof) knock-out (KO) mice. At P11, WT and KO inputs performed remarkably similarly. In WTs, the performance increased drastically between P11-P38, e.g. manifested by an 8 to 11-fold higher replenishment rate (RR) of synaptic vesicles (SVs) and action potential robustness. Together, these changes resulted in reliable and highly precise neurotransmission at frequencies ≤ 100 Hz. In contrast, KO inputs performed similarly at both ages, implying impaired synaptic maturation. Computational modeling confirmed the empirical observations and established a reduced RR per release site for P38 KOs. In conclusion, acoustic experience appears to contribute massively to the development of reliable neurotransmission, thereby forming the basis for effective ILD detection. Collectively, our results provide novel insights into experience-dependent maturation of inhibitory neurotransmission and auditory circuits at the synaptic level. Abstract figure legend MNTB-LSO inputs are a major component of the mammalian auditory brainstem. Reliable neurotransmission at these inputs requires both failure-free conduction of action potentials and robust synaptic transmission. The development of reliable neurotransmission depends crucially on functional hearing, as demonstrated in a time series and by the fact that deafness - upon loss of the protein otoferlin - results in severely impaired synaptic release and replenishment machineries. These findings from animal research may have some implications towards optimizing cochlear implant strategies on newborn humans. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nicolas I C Müller
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany.,Physiology of Neuronal Networks, Department of Biology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany
| | - Isabelle Paulußen
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany
| | - Lina N Hofmann
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany
| | - Jonas O Fisch
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany
| | - Abhyudai Singh
- 3Electrical & Computer Engineering, University of Delaware, Newark, DE, USA
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany
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Martínez-Valencia A, Ramírez-Santiago G, De-Miguel FF. Dynamics of Neuromuscular Transmission Reproduced by Calcium-Dependent and Reversible Serial Transitions in the Vesicle Fusion Complex. Front Synaptic Neurosci 2022; 13:785361. [PMID: 35242023 PMCID: PMC8885725 DOI: 10.3389/fnsyn.2021.785361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/30/2021] [Indexed: 11/28/2022] Open
Abstract
Neuromuscular transmission, from spontaneous release to facilitation and depression, was accurately reproduced by a mechanistic kinetic model of sequential maturation transitions in the molecular fusion complex. The model incorporates three predictions. First, calcium-dependent forward transitions take vesicles from docked to preprimed to primed states, followed by fusion. Second, prepriming and priming are reversible. Third, fusion and recycling are unidirectional. The model was fed with experimental data from previous studies, whereas the backward (β) and recycling (ρ) rate constant values were fitted. Classical experiments were successfully reproduced with four transition states in the model when every forward (α) rate constant had the same value, and both backward rate constants were 50–100 times larger. Such disproportion originated an abruptly decreasing gradient of resting vesicles from docked to primed states. By contrast, a three-state version of the model failed to reproduce the dynamics of transmission by using the same set of parameters. Simulations predict the following: (1) Spontaneous release reflects primed to fusion spontaneous transitions. (2) Calcium elevations synchronize the series of forward transitions that lead to fusion. (3) Facilitation reflects a transient increase of priming following the calcium-dependent maturation transitions. (4) The calcium sensors that produce facilitation are those that evoke the transitions form docked to primed states. (5) Backward transitions and recycling restore the resting state. (6) Depression reflects backward transitions and slow recycling after intense release. Altogether, our results predict that fusion is produced by one calcium sensor, whereas the modulation of the number of vesicles that fuse depends on the calcium sensors that promote the early transition states. Such finely tuned kinetics offers a mechanism for collective non-linear transitional adaptations of a homogeneous vesicle pool to the ever-changing pattern of electrical activity in the neuromuscular junction.
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Affiliation(s)
- Alejandro Martínez-Valencia
- Posgrado en Ciencias Físicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Francisco F. De-Miguel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- *Correspondence: Francisco F. De-Miguel,
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Huang W, Ke Y, Zhu J, Liu S, Cong J, Ye H, Guo Y, Wang K, Zhang Z, Meng W, Gao TM, Luhmann HJ, Kilb W, Chen R. TRESK channel contributes to depolarization-induced shunting inhibition and modulates epileptic seizures. Cell Rep 2021; 36:109404. [PMID: 34289346 DOI: 10.1016/j.celrep.2021.109404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/19/2021] [Accepted: 06/23/2021] [Indexed: 11/18/2022] Open
Abstract
Glutamatergic and GABAergic synaptic transmission controls excitation and inhibition of postsynaptic neurons, whereas activity of ion channels modulates neuronal intrinsic excitability. However, it is unclear how excessive neuronal excitation affects intrinsic inhibition to regain homeostatic stability under physiological or pathophysiological conditions. Here, we report that a seizure-like sustained depolarization can induce short-term inhibition of hippocampal CA3 neurons via a mechanism of membrane shunting. This depolarization-induced shunting inhibition (DShI) mediates a non-synaptic, but neuronal intrinsic, short-term plasticity that is able to suppress action potential generation and postsynaptic responses by activated ionotropic receptors. We demonstrate that the TRESK channel significantly contributes to DShI. Disruption of DShI by genetic knockout of TRESK exacerbates the sensitivity and severity of epileptic seizures of mice, whereas overexpression of TRESK attenuates seizures. In summary, these results uncover a type of homeostatic intrinsic plasticity and its underlying mechanism. TRESK might represent a therapeutic target for antiepileptic drugs.
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Affiliation(s)
- Weiyuan Huang
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yue Ke
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jianping Zhu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shuai Liu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jin Cong
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Hailin Ye
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yanwu Guo
- The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Kewan Wang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhenhai Zhang
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Center for Precision Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou 510030, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China
| | - Wenxiang Meng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tian-Ming Gao
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China; State Key Laboratory of Organ Failure Research, Collaborative Innovation Center for Brain Science, Southern Medical University, Guangzhou 510515, China
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany.
| | - Rongqing Chen
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China.
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Jacob T, Lillis KP, Wang Z, Swiercz W, Rahmati N, Staley KJ. A Proposed Mechanism for Spontaneous Transitions between Interictal and Ictal Activity. J Neurosci 2019; 39:557-575. [PMID: 30446533 PMCID: PMC6335741 DOI: 10.1523/jneurosci.0719-17.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 10/23/2018] [Accepted: 10/31/2018] [Indexed: 11/21/2022] Open
Abstract
Epileptic networks are characterized by two outputs: brief interictal spikes and rarer, more prolonged seizures. Although either output state is readily modeled in silico and induced experimentally, the transition mechanisms are unknown, in part because no models exhibit both output states spontaneously. In silico small-world neural networks were built using single-compartment neurons whose physiological parameters were derived from dual whole-cell recordings of pyramidal cells in organotypic hippocampal slice cultures that were generating spontaneous seizure-like activity. In silico, neurons were connected by abundant local synapses and rare long-distance synapses. Activity-dependent synaptic depression and gradual recovery delimited synchronous activity. Full synaptic recovery engendered interictal population spikes that spread via long-distance synapses. When synaptic recovery was incomplete, postsynaptic neurons required coincident activation of multiple presynaptic terminals to reach firing threshold. Only local connections were sufficiently dense to spread activity under these conditions. This coalesced network activity into traveling waves whose velocity varied with synaptic recovery. Seizures were comprised of sustained traveling waves that were similar to those recorded during experimental and human neocortical seizures. Sustained traveling waves occurred only when wave velocity, network dimensions, and the rate of synaptic recovery enabled wave reentry into previously depressed areas at precisely ictogenic levels of synaptic recovery. Wide-field, cellular-resolution GCamP7b calcium imaging demonstrated similar initial patterns of activation in the hippocampus, although the anatomical distribution of traveling waves of synaptic activation was altered by the pattern of synaptic connectivity in the organotypic hippocampal cultures.SIGNIFICANCE STATEMENT When computerized distributed neural network models are required to generate both features of epileptic networks (i.e., spontaneous interictal population spikes and seizures), the network structure is substantially constrained. These constraints provide important new hypotheses regarding the nature of epileptic networks and mechanisms of seizure onset.
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Affiliation(s)
- Theju Jacob
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Kyle P Lillis
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Zemin Wang
- Brigham and Women's Hospital, Boston, MA 02115, and
- Harvard Medical School, Boston, MA 02115
| | - Waldemar Swiercz
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Negah Rahmati
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Kevin J Staley
- Massachusetts General Hospital, Boston, Massachusetts 02114,
- Harvard Medical School, Boston, MA 02115
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Papaleonidopoulos V, Trompoukis G, Koutsoumpa A, Papatheodoropoulos C. A gradient of frequency-dependent synaptic properties along the longitudinal hippocampal axis. BMC Neurosci 2017; 18:79. [PMID: 29233091 PMCID: PMC5727934 DOI: 10.1186/s12868-017-0398-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/05/2017] [Indexed: 12/29/2022] Open
Abstract
Background The hippocampus is a functionally heterogeneous brain structure and specializations of the intrinsic neuronal network may crucially support the functional segregation along the longitudinal axis of the hippocampus. Short-term synaptic plasticity plays fundamental roles in information processing and may be importantly involved in diversifying the properties of local neuronal network along the hippocampus long axis. Therefore, we aimed to examine the properties of the cornu ammonis 1 (CA1) synapses along the entire dorsoventral axis of the rat hippocampus using field excitatory postsynaptic potentials from transverse rat hippocampal slices and a frequency stimulation paradigm. Results Applying a ten-pulse stimulus train at frequencies from 0.1 to 100 Hz to the Schaffer collaterals we found a gradually diversified pattern of frequency-dependent synaptic effects along the dorsoventral hippocampus axis. The first conditioned response was facilitated along the whole hippocampus for stimulus frequencies 10–40 Hz. However, steady-state responses or averaged responses generally ranged from maximum synaptic facilitation in the most dorsal segment of the hippocampus to maximum synaptic depression in the most ventral segment of the hippocampus. In particular, dorsal synapses facilitated for stimulus frequency up to 50 Hz while they depressed at higher frequencies (75–100 Hz). Facilitation at dorsal synapses was maximal at stimulus frequency of 20 Hz. On the contrary, the most ventral synapses showed depression regardless of the stimulus frequency, only displaying a transient facilitation at the beginning of 10–50 Hz stimulation. Importantly, the synapses in the medial hippocampus displayed a transitory behavior. Finally, as a whole the hippocampal synapses maximally facilitated at 20 Hz and increasingly depressed at 50–100 Hz. Conclusion The short-term synaptic dynamics change gradually along the hippocampal long axis in a frequency-dependent fashion conveying distinct properties of information processing to successive segments of the structure, thereby crucially supporting functional segregation along the dorsoventral axis of the hippocampus.
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Affiliation(s)
| | - George Trompoukis
- Department of Medicine, Laboratory of Physiology, University of Patras, 26504, Rion, Greece
| | - Andriana Koutsoumpa
- Department of Medicine, Laboratory of Physiology, University of Patras, 26504, Rion, Greece
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Neher E. Some Subtle Lessons from the Calyx of Held Synapse. Biophys J 2017; 112:215-223. [PMID: 28122210 PMCID: PMC5266140 DOI: 10.1016/j.bpj.2016.12.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/29/2016] [Accepted: 12/09/2016] [Indexed: 12/12/2022] Open
Abstract
The calyx of Held is a giant nerve terminal that forms a glutamatergic synapse in the auditory pathway. Due to its large size, it offers a number of advantages for biophysical studies, including voltage-clamp of both pre- and postsynaptic compartments and the loading with indicator dyes and caged compounds. Three aspects of recent findings on the calyx are reviewed here, each of which seems to have only subtle consequences for nerve-evoked excitatory postsynaptic currents: vesicle heterogeneity, refractoriness of release sites, and superpriming. Together, they determine short-term plasticity features that are superficially similar to those expected for a simple vesicle pool model. However, detailed consideration of these aspects may be required for the correct mechanistic interpretation of data from synapses with normal and perturbed function, as well as for modeling the dynamics of short-term plasticity.
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Affiliation(s)
- Erwin Neher
- Membrane Biophysics Laboratory, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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Barroso-Flores J, Herrera-Valdez MA, Galarraga E, Bargas J. Models of Short-Term Synaptic Plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1015:41-57. [PMID: 29080020 DOI: 10.1007/978-3-319-62817-2_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We focus on dynamical descriptions of short-term synaptic plasticity. Instead of focusing on the molecular machinery that has been reviewed recently by several authors, we concentrate on the dynamics and functional significance of synaptic plasticity, and review some mathematical models that reproduce different properties of the dynamics of short term synaptic plasticity that have been observed experimentally. The complexity and shortcomings of these models point to the need of simple, yet physiologically meaningful models. We propose a simplified model to be tested in synapses displaying different types of short-term plasticity.
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Affiliation(s)
- Janet Barroso-Flores
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, DF, 04510, Mexico.
| | - Marco A Herrera-Valdez
- Departamento de Matemáticas, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, DF, 04510, Mexico.
| | - Elvira Galarraga
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, DF, 04510, Mexico
| | - José Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, DF, 04510, Mexico
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Tissue-specific dynamin-1 deletion at the calyx of Held decreases short-term depression through a mechanism distinct from vesicle resupply. Proc Natl Acad Sci U S A 2016; 113:E3150-8. [PMID: 27185948 DOI: 10.1073/pnas.1520937113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dynamin is a large GTPase with a crucial role in synaptic vesicle regeneration. Acute dynamin inhibition impairs neurotransmitter release, in agreement with the protein's established role in vesicle resupply. Here, using tissue-specific dynamin-1 knockout [conditional knockout (cKO)] mice at a fast central synapse that releases neurotransmitter at high rates, we report that dynamin-1 deletion unexpectedly leads to enhanced steady-state neurotransmission and consequently less synaptic depression during brief periods of high-frequency stimulation. These changes are also accompanied by increased transmission failures. Interestingly, synaptic vesicle resupply and several other synaptic properties remain intact, including basal neurotransmission, presynaptic Ca(2+) influx, initial release probability, and postsynaptic receptor saturation and desensitization. However, acute application of Latrunculin B, a reagent known to induce actin depolymerization and impair bulk and ultrafast endocytosis, has a stronger effect on steady-state depression in cKO than in control and brings the depression down to a control level. The slow phase of presynaptic capacitance decay following strong stimulation is impaired in cKO; the rapid capacitance changes immediately after strong depolarization are also different between control and cKO and sensitive to Latrunculin B. These data raise the possibility that, in addition to its established function in regenerating synaptic vesicles, the endocytosis protein dynamin-1 may have an impact on short-term synaptic depression. This role comes into play primarily during brief high-frequency stimulation.
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Shah D, Praet J, Latif Hernandez A, Höfling C, Anckaerts C, Bard F, Morawski M, Detrez JR, Prinsen E, Villa A, De Vos WH, Maggi A, D'Hooge R, Balschun D, Rossner S, Verhoye M, Van der Linden A. Early pathologic amyloid induces hypersynchrony of BOLD resting-state networks in transgenic mice and provides an early therapeutic window before amyloid plaque deposition. Alzheimers Dement 2016; 12:964-976. [PMID: 27107518 DOI: 10.1016/j.jalz.2016.03.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/16/2016] [Accepted: 03/19/2016] [Indexed: 10/21/2022]
Abstract
INTRODUCTION In Alzheimer's disease (AD), pathologic amyloid-beta (Aβ) is synaptotoxic and impairs neuronal function at the microscale, influencing brain networks at the macroscale before Aβ deposition. The latter can be detected noninvasively, in vivo, using resting-state functional MRI (rsfMRI), a technique used to assess brain functional connectivity (FC). METHODS RsfMRI was performed longitudinally in TG2576 and PDAPP mice, starting before Aβ deposition to determine the earliest FC changes. Additionally, the role of pathologic Aβ on early FC alterations was investigated by treating TG2576 mice with the 3D6 anti-Aβ-antibody. RESULTS Both transgenic models showed hypersynchronized FC before Aβ deposition and hyposynchronized FC at later stages. Early anti-Aβ treatment in TG2576 mice prevented hypersynchronous FC and the associated synaptic impairments and excitatory/inhibitory disbalances. DISCUSSION Hypersynchrony of FC may be used as a new noninvasive read out of early AD and can be recovered by anti-Aβ treatment, encouraging preventive treatment strategies in familial AD.
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Affiliation(s)
- Disha Shah
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium.
| | - Jelle Praet
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Amira Latif Hernandez
- Laboratory of Biological Psychology, Department of Psychology, KU Leuven, Leuven, Belgium
| | - Corinna Höfling
- Paul Flechsig Institute for Brain Research, Leipzig, Germany
| | - Cynthia Anckaerts
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | | | - Markus Morawski
- Paul Flechsig Institute for Brain Research, Leipzig, Germany
| | - Jan R Detrez
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Els Prinsen
- Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Alessandro Villa
- Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Winnok H De Vos
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium; Cell Systems and Imaging, Department Molecular Biotechnology, University of Ghent, Ghent, Belgium
| | - Adriana Maggi
- Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Rudi D'Hooge
- Laboratory of Biological Psychology, Department of Psychology, KU Leuven, Leuven, Belgium
| | - Detlef Balschun
- Laboratory of Biological Psychology, Department of Psychology, KU Leuven, Leuven, Belgium
| | - Steffen Rossner
- Paul Flechsig Institute for Brain Research, Leipzig, Germany
| | - Marleen Verhoye
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Annemie Van der Linden
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
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Neher E. Merits and Limitations of Vesicle Pool Models in View of Heterogeneous Populations of Synaptic Vesicles. Neuron 2015; 87:1131-1142. [DOI: 10.1016/j.neuron.2015.08.038] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Striking differences in synaptic facilitation along the dorsoventral axis of the hippocampus. Neuroscience 2015; 301:454-70. [DOI: 10.1016/j.neuroscience.2015.06.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/07/2015] [Accepted: 06/18/2015] [Indexed: 12/23/2022]
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13
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Meneses D, Mateos V, Islas G, Barral J. G-protein-coupled inward rectifier potassium channels involved in corticostriatal presynaptic modulation. Synapse 2015; 69:446-52. [DOI: 10.1002/syn.21833] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 06/01/2015] [Accepted: 06/16/2015] [Indexed: 01/13/2023]
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14
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Diverse Short-Term Dynamics of Inhibitory Synapses Converging on Striatal Projection Neurons: Differential Changes in a Rodent Model of Parkinson's Disease. Neural Plast 2015; 2015:573543. [PMID: 26167304 PMCID: PMC4475734 DOI: 10.1155/2015/573543] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/20/2015] [Indexed: 02/08/2023] Open
Abstract
Most neurons in the striatum are projection neurons (SPNs) which make synapses with each other within distances of approximately 100 µm. About 5% of striatal neurons are GABAergic interneurons whose axons expand hundreds of microns. Short-term synaptic plasticity (STSP) between fast-spiking (FS) interneurons and SPNs and between SPNs has been described with electrophysiological and optogenetic techniques. It is difficult to obtain pair recordings from some classes of interneurons and due to limitations of actual techniques, no other types of STSP have been described on SPNs. Diverse STSPs may reflect differences in presynaptic release machineries. Therefore, we focused the present work on answering two questions: Are there different identifiable classes of STSP between GABAergic synapses on SPNs? And, if so, are synapses exhibiting different classes of STSP differentially affected by dopamine depletion? Whole-cell voltage-clamp recordings on SPNs revealed three classes of STSPs: depressing, facilitating, and biphasic (facilitating-depressing), in response to stimulation trains at 20 Hz, in a constant ionic environment. We then used the 6-hydroxydopamine (6-OHDA) rodent model of Parkinson's disease to show that synapses with different STSPs are differentially affected by dopamine depletion. We propose a general model of STSP that fits all the dynamics found in our recordings.
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15
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Synaptic plasticity in the auditory system: a review. Cell Tissue Res 2015; 361:177-213. [PMID: 25896885 DOI: 10.1007/s00441-015-2176-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/18/2015] [Indexed: 01/19/2023]
Abstract
Synaptic transmission via chemical synapses is dynamic, i.e., the strength of postsynaptic responses may change considerably in response to repeated synaptic activation. Synaptic strength is increased during facilitation, augmentation and potentiation, whereas a decrease in synaptic strength is characteristic for depression and attenuation. This review attempts to discuss the literature on short-term and long-term synaptic plasticity in the auditory brainstem of mammals and birds. One hallmark of the auditory system, particularly the inner ear and lower brainstem stations, is information transfer through neurons that fire action potentials at very high frequency, thereby activating synapses >500 times per second. Some auditory synapses display morphological specializations of the presynaptic terminals, e.g., calyceal extensions, whereas other auditory synapses do not. The review focuses on short-term depression and short-term facilitation, i.e., plastic changes with durations in the millisecond range. Other types of short-term synaptic plasticity, e.g., posttetanic potentiation and depolarization-induced suppression of excitation, will be discussed much more briefly. The same holds true for subtypes of long-term plasticity, like prolonged depolarizations and spike-time-dependent plasticity. We also address forms of plasticity in the auditory brainstem that do not comprise synaptic plasticity in a strict sense, namely short-term suppression, paired tone facilitation, short-term adaptation, synaptic adaptation and neural adaptation. Finally, we perform a meta-analysis of 61 studies in which short-term depression (STD) in the auditory system is opposed to short-term depression at non-auditory synapses in order to compare high-frequency neurons with those that fire action potentials at a lower rate. This meta-analysis reveals considerably less STD in most auditory synapses than in non-auditory ones, enabling reliable, failure-free synaptic transmission even at frequencies >100 Hz. Surprisingly, the calyx of Held, arguably the best-investigated synapse in the central nervous system, depresses most robustly. It will be exciting to reveal the molecular mechanisms that set high-fidelity synapses apart from other synapses that function much less reliably.
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de Jong APH, Fioravante D. Translating neuronal activity at the synapse: presynaptic calcium sensors in short-term plasticity. Front Cell Neurosci 2014; 8:356. [PMID: 25400547 PMCID: PMC4212674 DOI: 10.3389/fncel.2014.00356] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 10/09/2014] [Indexed: 01/03/2023] Open
Abstract
The complex manner in which patterns of presynaptic neural activity are translated into short-term plasticity (STP) suggests the existence of multiple presynaptic calcium (Ca(2+)) sensors, which regulate the amplitude and time-course of STP and are the focus of this review. We describe two canonical Ca(2+)-binding protein domains (C2 domains and EF-hands) and define criteria that need to be met for a protein to qualify as a Ca(2+) sensor mediating STP. With these criteria in mind, we discuss various forms of STP and identify established and putative Ca(2+) sensors. We find that despite the multitude of proposed sensors, only three are well established in STP: Munc13, protein kinase C (PKC) and synaptotagmin-7. For putative sensors, we pinpoint open questions and potential pitfalls. Finally, we discuss how the molecular properties and modes of action of Ca(2+) sensors can explain their differential involvement in STP and shape net synaptic output.
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Affiliation(s)
| | - Diasynou Fioravante
- Department of Neurobiology, Physiology and Behavior, Center for Neuroscience, University of California Davis Davis, CA, USA
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