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Peng Y, Bjelde A, Aceituno PV, Mittermaier FX, Planert H, Grosser S, Onken J, Faust K, Kalbhenn T, Simon M, Radbruch H, Fidzinski P, Schmitz D, Alle H, Holtkamp M, Vida I, Grewe BF, Geiger JRP. Directed and acyclic synaptic connectivity in the human layer 2-3 cortical microcircuit. Science 2024; 384:338-343. [PMID: 38635709 DOI: 10.1126/science.adg8828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/12/2024] [Indexed: 04/20/2024]
Abstract
The computational capabilities of neuronal networks are fundamentally constrained by their specific connectivity. Previous studies of cortical connectivity have mostly been carried out in rodents; whether the principles established therein also apply to the evolutionarily expanded human cortex is unclear. We studied network properties within the human temporal cortex using samples obtained from brain surgery. We analyzed multineuron patch-clamp recordings in layer 2-3 pyramidal neurons and identified substantial differences compared with rodents. Reciprocity showed random distribution, synaptic strength was independent from connection probability, and connectivity of the supragranular temporal cortex followed a directed and mostly acyclic graph topology. Application of these principles in neuronal models increased dimensionality of network dynamics, suggesting a critical role for cortical computation.
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Affiliation(s)
- Yangfan Peng
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Antje Bjelde
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Pau Vilimelis Aceituno
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, 8057 Zürich, Switzerland
| | - Franz X Mittermaier
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Henrike Planert
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Sabine Grosser
- Institute for Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Julia Onken
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Katharina Faust
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Thilo Kalbhenn
- Department of Neurosurgery (Evangelisches Klinikum Bethel), Medical School, Bielefeld University, 33617 Bielefeld, Germany
| | - Matthias Simon
- Department of Neurosurgery (Evangelisches Klinikum Bethel), Medical School, Bielefeld University, 33617 Bielefeld, Germany
| | - Helena Radbruch
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Pawel Fidzinski
- Clinical Study Center, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117 Berlin, Germany
| | - Dietmar Schmitz
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117 Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Henrik Alle
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Martin Holtkamp
- Epilepsy-Center Berlin-Brandenburg, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Benjamin F Grewe
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, 8057 Zürich, Switzerland
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
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Murphy R, Alle H, Geiger JRP, Storm JF. Estimation of persistent sodium-current density in rat hippocampal mossy fibre boutons: Correction of space-clamp errors. J Physiol 2024; 602:1703-1732. [PMID: 38594842 DOI: 10.1113/jp284657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 02/13/2024] [Indexed: 04/11/2024] Open
Abstract
We used whole-cell patch clamp to estimate the stationary voltage dependence of persistent sodium-current density (iNaP) in rat hippocampal mossy fibre boutons. Cox's method for correcting space-clamp errors was extended to the case of an isopotential compartment with attached neurites. The method was applied to voltage-ramp experiments, in which iNaP is assumed to gate instantaneously. The raw estimates of iNaP led to predicted clamp currents that were at variance with observation, hence an algorithm was devised to improve these estimates. Optionally, the method also allows an estimate of the membrane specific capacitance, although values of the axial resistivity and seal resistance must be provided. Assuming that membrane specific capacitance and axial resistivity were constant, we conclude that seal resistance continued to fall after adding TTX to the bath. This might have been attributable to a further deterioration of the seal after baseline rather than an unlikely effect of TTX. There was an increase in the membrane specific resistance in TTX. The reason for this is unknown, but it meant that iNaP could not be determined by simple subtraction. Attempts to account for iNaP with a Hodgkin-Huxley model of the transient sodium conductance met with mixed results. One thing to emerge was the importance of voltage shifts. Also, a large variability in previously reported values of transient sodium conductance in mossy fibre boutons made comparisons with our results difficult. Various other possible sources of error are discussed. Simulations suggest a role for iNaP in modulating the axonal attenuation of EPSPs. KEY POINTS: We used whole-cell patch clamp to estimate the stationary voltage dependence of persistent sodium-current density (iNaP) in rat hippocampal mossy fibre boutons, using a KCl-based internal (pipette) solution and correcting for the liquid junction potential (2 mV). Space-clamp errors and deterioration of the patch-clamp seal during the experiment were corrected for by compartmental modelling. Attempts to account for iNaP in terms of the transient sodium conductance met with mixed results. One possibility is that the transient sodium conductance is higher in mossy fibre boutons than in the axon shaft. The analysis illustrates the need to account for various voltage shifts (Donnan potentials, liquid junction potentials and, possibly, other voltage shifts). Simulations suggest a role for iNaP in modulating the axonal attenuation of excitatory postsynaptic potentials, hence analog signalling by dentate granule cells.
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Affiliation(s)
- Ricardo Murphy
- Institute for Basic Medical Sciences, Physiology Section, University of Oslo, Oslo, Norway
| | - Henrik Alle
- Charité-Universitätsmedizin Berlin corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
- Institut für Neurophysiologie, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg R P Geiger
- Charité-Universitätsmedizin Berlin corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
- Institut für Neurophysiologie, Charité Universitätsmedizin Berlin, Berlin, Germany
- Cluster of Excellence NeuroCure, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Johan F Storm
- Institute for Basic Medical Sciences, Physiology Section, University of Oslo, Oslo, Norway
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Rifat A, Ossola B, Bürli RW, Dawson LA, Brice NL, Rowland A, Lizio M, Xu X, Page K, Fidzinski P, Onken J, Holtkamp M, Heppner FL, Geiger JRP, Madry C. Differential contribution of THIK-1 K + channels and P2X7 receptors to ATP-mediated neuroinflammation by human microglia. J Neuroinflammation 2024; 21:58. [PMID: 38409076 PMCID: PMC10895799 DOI: 10.1186/s12974-024-03042-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/12/2024] [Indexed: 02/28/2024] Open
Abstract
Neuroinflammation is highly influenced by microglia, particularly through activation of the NLRP3 inflammasome and subsequent release of IL-1β. Extracellular ATP is a strong activator of NLRP3 by inducing K+ efflux as a key signaling event, suggesting that K+-permeable ion channels could have high therapeutic potential. In microglia, these include ATP-gated THIK-1 K+ channels and P2X7 receptors, but their interactions and potential therapeutic role in the human brain are unknown. Using a novel specific inhibitor of THIK-1 in combination with patch-clamp electrophysiology in slices of human neocortex, we found that THIK-1 generated the main tonic K+ conductance in microglia that sets the resting membrane potential. Extracellular ATP stimulated K+ efflux in a concentration-dependent manner only via P2X7 and metabotropic potentiation of THIK-1. We further demonstrated that activation of P2X7 was mandatory for ATP-evoked IL-1β release, which was strongly suppressed by blocking THIK-1. Surprisingly, THIK-1 contributed only marginally to the total K+ conductance in the presence of ATP, which was dominated by P2X7. This suggests a previously unknown, K+-independent mechanism of THIK-1 for NLRP3 activation. Nuclear sequencing revealed almost selective expression of THIK-1 in human brain microglia, while P2X7 had a much broader expression. Thus, inhibition of THIK-1 could be an effective and, in contrast to P2X7, microglia-specific therapeutic strategy to contain neuroinflammation.
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Affiliation(s)
- Ali Rifat
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Bernardino Ossola
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Roland W Bürli
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Lee A Dawson
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Nicola L Brice
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Anna Rowland
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Marina Lizio
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Xiao Xu
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Keith Page
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge, CB4 0PZ, UK
| | - Pawel Fidzinski
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Neurocure Cluster of Excellence, Neuroscience Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Julia Onken
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Martin Holtkamp
- Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Frank L Heppner
- Neurocure Cluster of Excellence, Neuroscience Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Christian Madry
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117, Berlin, Germany.
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Hadler MD, Tzilivaki A, Schmitz D, Alle H, Geiger JRP. Gamma oscillation plasticity is mediated via parvalbumin interneurons. Sci Adv 2024; 10:eadj7427. [PMID: 38295164 PMCID: PMC10830109 DOI: 10.1126/sciadv.adj7427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024]
Abstract
Understanding the plasticity of neuronal networks is an emerging field of (patho-) physiological research, yet the underlying cellular mechanisms remain poorly understood. Gamma oscillations (30 to 80 hertz), a biomarker of cognitive performance, require and potentiate glutamatergic transmission onto parvalbumin-positive interneurons (PVIs), suggesting an interface for cell-to-network plasticity. In ex vivo local field potential recordings, we demonstrate long-term potentiation of hippocampal gamma power. Gamma potentiation obeys established rules of PVI plasticity, requiring calcium-permeable AMPA receptors (CP-AMPARs) and metabotropic glutamate receptors (mGluRs). A microcircuit computational model of CA3 gamma oscillations predicts CP-AMPAR plasticity onto PVIs critically outperforms pyramidal cell plasticity in increasing gamma power and completely accounts for gamma potentiation. We reaffirm this ex vivo in three PVI-targeting animal models, demonstrating that gamma potentiation requires PVI-specific signaling via a Gq/PKC pathway comprising mGluR5 and a Gi-sensitive, PKA-dependent pathway. Gamma activity-dependent, metabotropically mediated CP-AMPAR plasticity on PVIs may serve as a guiding principle in understanding network plasticity in health and disease.
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Affiliation(s)
- Michael D. Hadler
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Alexandra Tzilivaki
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charitéplatz 1, 10117 Berlin, Germany
- Neurocure Cluster of Excellence, Charitéplatz 1, 10117 Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
- Einstein Center for Neurosciences Berlin, Charitéplatz 1, 10117 Berlin, Germany
- Neurocure Cluster of Excellence, Charitéplatz 1, 10117 Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Bernstein Center for Computational Neuroscience, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert Rössle-Straße 10, 13125 Berlin, Germany
| | - Henrik Alle
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg R. P. Geiger
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Wildner F, Neuhäusel TS, Klemz A, Kovács R, Ulmann L, Geiger JRP, Gerevich Z. Extracellular ATP inhibits excitatory synaptic input on parvalbumin positive interneurons and attenuates gamma oscillations via P2X4 receptors. Br J Pharmacol 2023. [PMID: 38073073 DOI: 10.1111/bph.16298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND AND PURPOSE P2X4 receptors (P2X4R) are ligand gated cation channels that are activated by extracellular ATP released by neurons and glia. The receptors are widely expressed in the brain and have fractional calcium currents comparable with NMDA receptors. Although P2X4Rs have been reported to modulate synaptic transmission and plasticity, their involvement in shaping neuronal network activity remains to be elucidated. EXPERIMENTAL APPROACH We investigated the effects of P2X receptors at network and synaptic level using local field potential electrophysiology, whole cell patch clamp recordings and calcium imaging in fast spiking parvalbumin positive interneurons (PVINs) in rat and mouse hippocampal slices. The stable ATP analogue ATPγS, selective antagonists and P2X4R knockout mice were used. KEY RESULTS The P2XR agonist ATPγS reversibly decreased the power of gamma oscillations. This inhibition could be antagonized by the selective P2X4R antagonist PSB-12062 and was not observed in P2X4-/- mice. The phasic excitatory inputs of CA3 PVINs were one of the main regulators of the gamma power. Associational fibre compound excitatory postsynaptic currents (cEPSCs) in CA3 PVINs were inhibited by P2X4R activation. This effect was reversible, dependent on intracellular calcium and dynamin-dependent internalization of AMPA receptors. CONCLUSIONS AND IMPLICATIONS The results indicate that P2X4Rs are an important source of dendritic calcium in CA3 PVINs, thereby regulating excitatory synaptic inputs onto the cells and presumably the state of gamma oscillations in the hippocampus. P2X4Rs represent an effective target to modulate hippocampal network activity in pathophysiological conditions such as Alzheimer's disease and schizophrenia.
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Affiliation(s)
- Florian Wildner
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Tim S Neuhäusel
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Alexander Klemz
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Richard Kovács
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Lauriane Ulmann
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Zoltan Gerevich
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
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Günther DM, Kovacs R, Wildner F, Salivara A, Thalheimer FB, Fries P, Geiger JRP, Buchholz CJ. Substantially improved gene transfer to interneurons with second-generation glutamate receptor-targeted DART-AAV vectors. J Neurosci Methods 2023; 399:109981. [PMID: 37783350 DOI: 10.1016/j.jneumeth.2023.109981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/10/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
BACKGROUND Adeno-associated viral vectors (AAVs) are a widely used gene transfer platform in neuroscience. Although naturally AAV serotypes can have preferences for certain tissues, selectivity for particular cell types in the CNS does not exist. Towards interneuron targeting, capsid engineering of AAV2 including display of the designed ankyrin repeat protein (DARPin) 2K19 specific for the glutamate receptor subunit 4 (GluA4) at the N-terminus of the VP2 capsid protein has been established. The resulting AAV-VP2N is highly specific for interneurons, but exhibits rather moderate transduction efficiencies. METHODS Two alternative insertion sites for 2K19 in the GH2/GH3 loop of capsid proteins VP1 (AAV-VP1L) or VP2 (AAV-VP2L) were exploited to yield second generation GluA4-AAVs. Having packaged reporter genes under ubiquitous promoters, the vectors were characterized for biochemical properties as well as gene delivery into cell lines and rat hippocampal slice cultures. Electrophysiological recordings monitored the functional properties of transduced cells. RESULTS Compared to AAV-VP2N, the second-generation vectors, especially AAV-VP1L, achieved about 2-fold higher genomic titers as well as a substantially improved GluA4 binding. Improvements in gene transfer activities were 18-fold on GluA4-overexpressing A549 cells and five-fold on rat hippocampal organotypic slice cultures reaching approximately 60 % of all parvalbumin positive interneurons upon a single administration. The spiking behaviour of transduced cells was unaltered and characteristic for a heterogeneous group of interneurons. CONCLUSION The substantially improved gene transfer activity of the second generation GluA4-targeted AAV combined with low toxicity makes this vector an attractive tool for interneuron-directed gene transfer with unrestricted promotor and transgene choice.
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Affiliation(s)
- D M Günther
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany
| | - R Kovacs
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117 Berlin, Germany
| | - F Wildner
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117 Berlin, Germany
| | - A Salivara
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117 Berlin, Germany
| | - F B Thalheimer
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, 63225 Langen, Germany
| | - P Fries
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 EN Nijmegen, the Netherlands
| | - J R P Geiger
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117 Berlin, Germany
| | - C J Buchholz
- Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, 63225 Langen, Germany.
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Peng Y, Schöneberg N, Esposito MS, Geiger JRP, Sharott A, Tovote P. Current approaches to characterize micro- and macroscale circuit mechanisms of Parkinson's disease in rodent models. Exp Neurol 2022; 351:114008. [PMID: 35149118 PMCID: PMC7612860 DOI: 10.1016/j.expneurol.2022.114008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 01/17/2022] [Accepted: 02/04/2022] [Indexed: 11/24/2022]
Abstract
Accelerating technological progress in experimental neuroscience is increasing the scale as well as specificity of both observational and perturbational approaches to study circuit physiology. While these techniques have also been used to study disease mechanisms, a wider adoption of these approaches in the field of experimental neurology would greatly facilitate our understanding of neurological dysfunctions and their potential treatments at cellular and circuit level. In this review, we will introduce classic and novel methods ranging from single-cell electrophysiological recordings to state-of-the-art calcium imaging and cell-type specific optogenetic or chemogenetic stimulation. We will focus on their application in rodent models of Parkinson’s disease while also presenting their use in the context of motor control and basal ganglia function. By highlighting the scope and limitations of each method, we will discuss how they can be used to study pathophysiological mechanisms at local and global circuit levels and how novel frameworks can help to bridge these scales.
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Affiliation(s)
- Yangfan Peng
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; Department of Neurology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; MRC Brain Network Dynamics Unit, University of Oxford, Mansfield Road, Oxford OX1 3TH, United Kingdom.
| | - Nina Schöneberg
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Versbacher Str. 5, 97078 Wuerzburg, Germany
| | - Maria Soledad Esposito
- Medical Physics Department, Centro Atomico Bariloche, Comision Nacional de Energia Atomica (CNEA), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Av. E. Bustillo 9500, R8402AGP San Carlos de Bariloche, Rio Negro, Argentina
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Andrew Sharott
- MRC Brain Network Dynamics Unit, University of Oxford, Mansfield Road, Oxford OX1 3TH, United Kingdom
| | - Philip Tovote
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Versbacher Str. 5, 97078 Wuerzburg, Germany; Center for Mental Health, University of Wuerzburg, Margarete-Höppel-Platz 1, 97080 Wuerzburg, Germany.
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8
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Peng Y, Barreda Tomas FJ, Pfeiffer P, Drangmeister M, Schreiber S, Vida I, Geiger JRP. Spatially structured inhibition defined by polarized parvalbumin interneuron axons promotes head direction tuning. Sci Adv 2021; 7:7/25/eabg4693. [PMID: 34134979 PMCID: PMC8208710 DOI: 10.1126/sciadv.abg4693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/04/2021] [Indexed: 05/04/2023]
Abstract
In cortical microcircuits, it is generally assumed that fast-spiking parvalbumin interneurons mediate dense and nonselective inhibition. Some reports indicate sparse and structured inhibitory connectivity, but the computational relevance and the underlying spatial organization remain unresolved. In the rat superficial presubiculum, we find that inhibition by fast-spiking interneurons is organized in the form of a dominant super-reciprocal microcircuit motif where multiple pyramidal cells recurrently inhibit each other via a single interneuron. Multineuron recordings and subsequent 3D reconstructions and analysis further show that this nonrandom connectivity arises from an asymmetric, polarized morphology of fast-spiking interneuron axons, which individually cover different directions in the same volume. Network simulations assuming topographically organized input demonstrate that such polarized inhibition can improve head direction tuning of pyramidal cells in comparison to a "blanket of inhibition." We propose that structured inhibition based on asymmetrical axons is an overarching spatial connectivity principle for tailored computation across brain regions.
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Affiliation(s)
- Yangfan Peng
- Institute for Neurophysiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Federico J Barreda Tomas
- Institute for Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
- Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - Paul Pfeiffer
- Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115 Berlin, Germany
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Moritz Drangmeister
- Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115 Berlin, Germany
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Susanne Schreiber
- Bernstein Center for Computational Neuroscience Berlin, Philippstr. 13, 10115 Berlin, Germany
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
| | - Jörg R P Geiger
- Institute for Neurophysiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
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9
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Gotti GC, Kikhia M, Wuntke V, Hasam-Henderson LA, Wu B, Geiger JRP, Kovacs R. In situ labeling of non-accommodating interneurons based on metabolic rates. Redox Biol 2020; 38:101798. [PMID: 33285412 PMCID: PMC7724199 DOI: 10.1016/j.redox.2020.101798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 11/25/2022] Open
Abstract
Maintaining high frequency firing of narrow action potentials puts a large metabolic load on fast spiking (FS), perisomatic-inhibitory interneurons compared to their slow-spiking, dendrite targeting counterparts. Although the relationship of action potential (AP) firing and metabolism is firmly established, there is no single method to differentiate interneurons in situ based on their firing properties. In this study, we explore a novel strategy to easily identify the metabolically active FS cells among different classes of interneurons. We found that the oxidation of the fluorescent free radical marker 2,7-dichlorodihydrofluorescein (H2DCF) preferentially occurs in interneurons both in slice cultures and acute brain slices. Despite their morphological heterogeneity, almost all DCF-positive (DCF+) neurons belonged to the cluster of non-accommodating FS interneurons. Furthermore, all FS interneurons expressing parvalbumin (PV) both in slice cultures and in acute slices from tdTomato-PVCre transgenic mice were also DCF+. However, only half of the recorded DCF + cells were also PV+, indicating that H2DCF-oxidation occurs in different interneuron classes characterized by non-accomodating AP-firing. Comprehensively enhancing spontaneous neuronal activity led to mitochondrial oxidation of DCF in pyramidal cells as well as interneurons, suggesting that the apparent selectivity towards interneurons represents differences in the underlying metabolic load. While radical-scavenging, inhibition of APs or NO-synthesis, and iron chelation had no effect on the staining pattern, exposure to the complex-I inhibitor, rotenone, prevented interneuronal DCF accumulation. We conclude that H2DCF oxidation is independent of free radicals but correlates with the intensive oxidative energy metabolism and high mitochondrial mass in interneurons sharing the non-accommodating FS phenotype. Fast spiking non-adapting interneurons preferentially oxidize and accumulate H2DCF. Labeling of interneurons correlates with mitochondrial mass and energy metabolism. Free radical formation does not contribute to DCF-labeling of interneurons.
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Affiliation(s)
- G C Gotti
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany
| | - M Kikhia
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany
| | - V Wuntke
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany
| | - L A Hasam-Henderson
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany
| | - B Wu
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany; Institute of Neuroinformatics, University of Zurich - Irchel, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - J R P Geiger
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany
| | - R Kovacs
- Institut für Neurophysiologie, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, NeuroCure Cluster of Excellence, Berlin, Charité Platz 1, 10117, Berlin, Germany.
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10
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Oltmanns S, Abben FS, Ender A, Aimon S, Kovacs R, Sigrist SJ, Storace DA, Geiger JRP, Raccuglia D. NOSA, an Analytical Toolbox for Multicellular Optical Electrophysiology. Front Neurosci 2020; 14:712. [PMID: 32765213 PMCID: PMC7381214 DOI: 10.3389/fnins.2020.00712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/12/2020] [Indexed: 11/23/2022] Open
Abstract
Understanding how neural networks generate activity patterns and communicate with each other requires monitoring the electrical activity from many neurons simultaneously. Perfectly suited tools for addressing this challenge are genetically encoded voltage indicators (GEVIs) because they can be targeted to specific cell types and optically report the electrical activity of individual, or populations of neurons. However, analyzing and interpreting the data from voltage imaging experiments is challenging because high recording speeds and properties of current GEVIs yield only low signal-to-noise ratios, making it necessary to apply specific analytical tools. Here, we present NOSA (Neuro-Optical Signal Analysis), a novel open source software designed for analyzing voltage imaging data and identifying temporal interactions between electrical activity patterns of different origin. In this work, we explain the challenges that arise during voltage imaging experiments and provide hands-on analytical solutions. We demonstrate how NOSA's baseline fitting, filtering algorithms and movement correction can compensate for shifts in baseline fluorescence and extract electrical patterns from low signal-to-noise recordings. NOSA allows to efficiently identify oscillatory frequencies in electrical patterns, quantify neuronal response parameters and moreover provides an option for analyzing simultaneously recorded optical and electrical data derived from patch-clamp or other electrode-based recordings. To identify temporal relations between electrical activity patterns we implemented different options to perform cross correlation analysis, demonstrating their utility during voltage imaging in Drosophila and mice. All features combined, NOSA will facilitate the first steps into using GEVIs and help to realize their full potential for revealing cell-type specific connectivity and functional interactions.
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Affiliation(s)
- Sebastian Oltmanns
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Frauke Sophie Abben
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anatoli Ender
- German Center for Neurodegenerative Diseases, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Sophie Aimon
- School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Richard Kovacs
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stephan J. Sigrist
- German Center for Neurodegenerative Diseases, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Institute of Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Douglas A. Storace
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Jörg R. P. Geiger
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Davide Raccuglia
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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11
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Hasam-Henderson LA, Gotti GC, Mishto M, Klisch C, Gerevich Z, Geiger JRP, Kovács R. Author Correction: NMDA-receptor inhibition and oxidative stress during hippocampal maturation differentially alter parvalbumin expression and gamma-band activity. Sci Rep 2018; 8:13170. [PMID: 30154442 PMCID: PMC6113328 DOI: 10.1038/s41598-018-31011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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12
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Peng Y, Barreda Tomás FJ, Klisch C, Vida I, Geiger JRP. Layer-Specific Organization of Local Excitatory and Inhibitory Synaptic Connectivity in the Rat Presubiculum. Cereb Cortex 2017; 27:2435-2452. [PMID: 28334142 PMCID: PMC5390487 DOI: 10.1093/cercor/bhx049] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 02/10/2017] [Indexed: 12/13/2022] Open
Abstract
The presubiculum is part of the parahippocampal spatial navigation system and contains head direction and grid cells upstream of the medial entorhinal cortex. This position within the parahippocampal cortex renders the presubiculum uniquely suited for analyzing the circuit requirements underlying the emergence of spatially tuned neuronal activity. To identify the local circuit properties, we analyzed the topology of synaptic connections between pyramidal cells and interneurons in all layers of the presubiculum by testing 4250 potential synaptic connections using multiple whole-cell recordings of up to 8 cells simultaneously. Network topology showed layer-specific organization of microcircuits consistent with the prevailing distinction of superficial and deep layers. While connections among pyramidal cells were almost absent in superficial layers, deep layers exhibited an excitatory connectivity of 3.9%. In contrast, synaptic connectivity for inhibition was higher in superficial layers though markedly lower than in other cortical areas. Finally, synaptic amplitudes of both excitatory and inhibitory connections showed log-normal distributions suggesting a nonrandom functional connectivity. In summary, our study provides new insights into the microcircuit organization of the presubiculum by revealing area- and layer-specific connectivity rules and sets new constraints for future models of the parahippocampal navigation system.
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Affiliation(s)
- Yangfan Peng
- Institute of Neurophysiology, Charité - Universitätsmedizin, 10117 Berlin, Germany
| | | | - Constantin Klisch
- Institute of Neurophysiology, Charité - Universitätsmedizin, 10117 Berlin, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin, 10117 Berlin, Germany.,NeuroCure Cluster of Excellence, Charité - Universitätsmedizin, 10117 Berlin, Germany
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin, 10117 Berlin, Germany.,NeuroCure Cluster of Excellence, Charité - Universitätsmedizin, 10117 Berlin, Germany
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13
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Franke F, Pröpper R, Alle H, Meier P, Geiger JRP, Obermayer K, Munk MHJ. Spike sorting of synchronous spikes from local neuron ensembles. J Neurophysiol 2015; 114:2535-49. [PMID: 26289473 DOI: 10.1152/jn.00993.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 08/14/2015] [Indexed: 11/22/2022] Open
Abstract
Synchronous spike discharge of cortical neurons is thought to be a fingerprint of neuronal cooperativity. Because neighboring neurons are more densely connected to one another than neurons that are located further apart, near-synchronous spike discharge can be expected to be prevalent and it might provide an important basis for cortical computations. Using microelectrodes to record local groups of neurons does not allow for the reliable separation of synchronous spikes from different cells, because available spike sorting algorithms cannot correctly resolve the temporally overlapping waveforms. We show that high spike sorting performance of in vivo recordings, including overlapping spikes, can be achieved with a recently developed filter-based template matching procedure. Using tetrodes with a three-dimensional structure, we demonstrate with simulated data and ground truth in vitro data, obtained by dual intracellular recording of two neurons located next to a tetrode, that the spike sorting of synchronous spikes can be as successful as the spike sorting of nonoverlapping spikes and that the spatial information provided by multielectrodes greatly reduces the error rates. We apply the method to tetrode recordings from the prefrontal cortex of behaving primates, and we show that overlapping spikes can be identified and assigned to individual neurons to study synchronous activity in local groups of neurons.
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Affiliation(s)
- Felix Franke
- Technische Universität Berlin, School for Electrical Engineering and Computer Science, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany;
| | - Robert Pröpper
- Technische Universität Berlin, School for Electrical Engineering and Computer Science, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany
| | | | - Philipp Meier
- Technische Universität Berlin, School for Electrical Engineering and Computer Science, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany
| | | | - Klaus Obermayer
- Technische Universität Berlin, School for Electrical Engineering and Computer Science, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany
| | - Matthias H J Munk
- Fachbereich Biologie, Technische Universität Darmstadt, Darmstadt, Germany; and Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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14
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Madry C, Betz H, Geiger JRP, Laube B. Potentiation of Glycine-Gated NR1/NR3A NMDA Receptors Relieves Ca-Dependent Outward Rectification. Front Mol Neurosci 2010; 3:6. [PMID: 20407581 PMCID: PMC2854533 DOI: 10.3389/fnmol.2010.00006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 03/04/2010] [Indexed: 11/20/2022] Open
Abstract
Glycine has diverse functions within the mammalian central nervous system. It inhibits postsynaptic neurons via strychnine-sensitive glycine receptors (GlyRs) and enhances neuronal excitation through co-activation of N-methyl-D-aspartate (NMDA) receptors. Classical Ca2+-permeable NMDA receptors are composed of glycine-binding NR1 and glutamate-binding NR2 subunits, and hence require both glutamate and glycine for efficient activation. In contrast, recombinant receptors composed of NR1 and the glycine binding NR3A and/or NR3B subunits lack glutamate binding sites and can be activated by glycine alone. Therefore these receptors are also named “excitatory glycine receptors”. Co-application of antagonists of the NR1 glycine-binding site or of the divalent cation Zn2+ markedly enhances the glycine responses of these receptors. To gain further insight into the properties of these glycine-gated NMDA receptors, we investigated their current-voltage (I–V) dependence. Whole-cell current-voltage relations of glycine currents recorded from NR1/NR3B and NR1/NR3A/NR3B expressing oocytes were found to be linear under our recording conditions. In contrast, NR1/NR3A receptors displayed a strong outwardly rectifying I–V relation. Interestingly, the voltage-dependent inward current block was abolished in the presence of NR1 antagonists, Zn2+ or a combination of both. Further analysis revealed that Ca2+ (1.8 mM) present in our recording solutions was responsible for the voltage-dependent inhibition of ion flux through NR1/NR3A receptors. Since physiological concentrations of the divalent cation Mg2+ did not affect the I–V dependence, our data suggest that relief of the voltage-dependent Ca2+ block of NR1/NR3A receptors by Zn2+ may be important for the regulation of excitatory glycinergic transmission, according to the Mg2+-block of conventional NR1/NR2 NMDA receptors.
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Affiliation(s)
- Christian Madry
- Department of Neurochemistry, Max-Planck Institute for Brain Research Frankfurt am Main, Germany
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15
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Kubota H, Alle H, Betz H, Geiger JRP. Presynaptic glycine receptors on hippocampal mossy fibers. Biochem Biophys Res Commun 2010; 393:587-91. [PMID: 20152805 DOI: 10.1016/j.bbrc.2010.02.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 02/05/2010] [Indexed: 11/30/2022]
Abstract
Presynaptic glycine receptors (GlyRs) have been implicated in the regulation of glutamatergic synaptic transmission. Here, we characterized presynaptic GlyR-mediated currents by patch-clamp recording from mossy fiber boutons (MFBs) in rat hippocampal slices. In MFBs, focal puff-application of glycine-evoked chloride currents that were blocked by the GlyR antagonist strychnine. Their amplitudes declined substantially during postnatal development, from a mean conductance per MFB of approximately 600 pS in young to approximately 130 pS in adult animals. Single-channel analysis revealed multiple conductance states between approximately 20 and approximately 120 pS, consistent with expression of both homo- and hetero-oligomeric GlyRs. Accordingly, estimated GlyRs densities varied between 8-17 per young, and 1-3 per adult, MFB. Our results demonstrate that functional presynaptic GlyRs are present on hippocampal mossy fiber terminals and suggest a role of these receptors in the regulation of glutamate release during the development of the mossy fiber--CA3 synapse.
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Affiliation(s)
- Hisahiko Kubota
- Independent Hertie Research Group, Max-Planck Institute for Brain Research, D-60528 Frankfurt am Main, Germany
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16
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Abstract
Action potentials in nonmyelinated axons are considered to contribute substantially to activity-dependent brain metabolism. Here we show that fast Na+ current decay and delayed K+ current onset during action potentials in nonmyelinated mossy fibers of the rat hippocampus minimize the overlap of their respective ion fluxes. This results in total Na+ influx and associated energy demand per action potential of only 1.3 times the theoretical minimum, in contrast to the factor of 4 used in previous energy budget calculations for neural activity. Analysis of ionic conductance parameters revealed that the properties of Na+ and K+ channels are matched to make axonal action potentials energy-efficient, minimizing their contribution to activity-dependent metabolism.
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Affiliation(s)
- Henrik Alle
- Independent Hertie Research Group, Max-Planck-Institute for Brain Research, 60528 Frankfurt, Germany.
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17
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Alle H, Geiger JRP. Analog signalling in mammalian cortical axons. Curr Opin Neurobiol 2009; 18:314-20. [PMID: 18801430 DOI: 10.1016/j.conb.2008.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 08/14/2008] [Accepted: 08/18/2008] [Indexed: 10/21/2022]
Abstract
In the mammalian cortex, the classic view assumes that the output information of a neuron is encoded in rather stereotyped action potentials, which provide an all-or-none or digital way of communication between cell body and axonal boutons. A role for subthreshold signal propagation within cortical axons has largely been ignored. Recent achievements of direct recordings from axonal structures in the hippocampus and neocortex extended the classic view by the observation that subthreshold-graded signals propagate down the axon over distances of up to 1 mm. At certain synapses, these analog axonal signals modulate action-potential-dependent transmitter release, thereby enabling a hybrid code of information transmission in local cortical circuits.
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Affiliation(s)
- Henrik Alle
- Independent Hertie Research Group, Max-Planck-Institute for Brain Research, D-60528 Frankfurt, Germany
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18
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Abstract
Rigorous analysis of synaptic transmission in the central nervous system requires access to presynaptic terminals. However, cortical terminals have been largely inaccessible to presynaptic patch-clamp recording, due to their small size. Using improved patch-clamp techniques in brain slices, we recorded from mossy fiber terminals in the CA3 region of the hippocampus, which have a diameter of 2-5 microm. The major steps of improvement were the enhanced visibility provided by high-numerical aperture objectives and infrared illumination, the development of vibratomes with minimal vertical blade vibrations and the use of sucrose-based solutions for storage and cutting. Based on these improvements, we describe a protocol that allows us to routinely record from hippocampal mossy fiber boutons. Presynaptic recordings can be obtained in slices from both rats and mice. Presynaptic recordings can be also obtained in slices from transgenic mice in which terminals are labeled with enhanced green fluorescent protein.
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Affiliation(s)
- Josef Bischofberger
- Institute of Physiology, University of Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany
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19
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Papadopoulos T, Korte M, Eulenburg V, Kubota H, Retiounskaia M, Harvey RJ, Harvey K, O'Sullivan GA, Laube B, Hülsmann S, Geiger JRP, Betz H. Impaired GABAergic transmission and altered hippocampal synaptic plasticity in collybistin-deficient mice. EMBO J 2007; 26:3888-99. [PMID: 17690689 PMCID: PMC1994120 DOI: 10.1038/sj.emboj.7601819] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 07/19/2007] [Indexed: 11/09/2022] Open
Abstract
Collybistin (Cb) is a brain-specific guanine nucleotide exchange factor that has been implicated in plasma membrane targeting of the postsynaptic scaffolding protein gephyrin found at glycinergic and GABAergic synapses. Here we show that Cb-deficient mice display a region-specific loss of postsynaptic gephyrin and GABA(A) receptor clusters in the hippocampus and the basolateral amygdala. Cb deficiency is accompanied by significant changes in hippocampal synaptic plasticity, due to reduced dendritic GABAergic inhibition. Long-term potentiation is enhanced, and long-term depression reduced, in Cb-deficient hippocampal slices. Consistent with the anatomical and electrophysiological findings, the animals show increased levels of anxiety and impaired spatial learning. Together, our data indicate that Cb is essential for gephyrin-dependent clustering of a specific set of GABA(A) receptors, but not required for glycine receptor postsynaptic localization.
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Affiliation(s)
- Theofilos Papadopoulos
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Martin Korte
- Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
| | - Volker Eulenburg
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Hisahiko Kubota
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
- Independent Hertie Research Group, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Marina Retiounskaia
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Robert J Harvey
- Department of Pharmacology, The School of Pharmacy, London, UK
| | - Kirsten Harvey
- Department of Pharmacology, The School of Pharmacy, London, UK
| | - Gregory A O'Sullivan
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Bodo Laube
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Swen Hülsmann
- Department of Neuro- and Sensory Physiology, University of Göttingen, Göttingen, Germany
| | - Jörg R P Geiger
- Independent Hertie Research Group, Max-Planck-Institute for Brain Research, Frankfurt, Germany
| | - Heinrich Betz
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Frankfurt, Germany
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Deutschordenstrassee 46, 60528 Frankfurt am Main, Germany. Tel.: +49 69 96769 220; Fax: +49 69 96769 441; E-mail:
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20
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Abstract
Presynaptic ionotropic GABA(A) receptors have been suggested to contribute to the regulation of cortical glutamatergic synaptic transmission. Here, we analyzed presynaptic GABA(A) receptor-mediated currents (34 degrees C) recorded from mossy fiber boutons (MFBs) in rat hippocampal slices. In MFBs from young and adult animals, GABA puff application activated currents that were blocked by GABA(A) receptor antagonists. The conductance density of 0.65 mS x cm2 was comparable to that of other presynaptic terminals. The single-channel conductance was 36 pS (symmetrical chloride), yielding an estimated GABA(A) receptor density of 20-200 receptors per MFB. Presynaptic GABA(A) receptors likely contain alpha2-subunits as indicated by their zolpidem sensitivity. In accordance with the low apparent GABA affinity (EC50 = 60 microM) of the receptors and a tight control of ambient GABA concentration by GABA transporters, no tonic background activation of presynaptic GABA(A) receptors was observed. Instead, extracellular high-frequency stimulation led to transient presynaptic currents, which were blocked by GABA(A) receptor antagonists but were enhanced by block of GAT 1 (GABA transporter 1), indicating that these currents were generated by GABA spill-over and subsequent presynaptic GABA(A) receptor activation. Presynaptic spill-over currents were depressed by pharmacological cannabinoid 1 (CB1) receptor activation, suggesting that GABA was released predominantly by a CB1 receptor-expressing interneuron subpopulation. Because GABA(A) receptors in axons are considered to act depolarizing, high activity of CB1 receptor-expressing interneurons will exert substantial impact on presynaptic membrane potential, thus modulating action potential-evoked transmitter release at the mossy fiber-CA3 synapse.
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Affiliation(s)
- Henrik Alle
- Independent Hertie Research Group, Max Planck Institute for Brain Research, D-60528 Frankfurt, Germany
| | - Jörg R. P. Geiger
- Independent Hertie Research Group, Max Planck Institute for Brain Research, D-60528 Frankfurt, Germany
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21
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Abstract
In the mammalian cortex, it is generally assumed that the output information of neurons is encoded in the number and the timing of action potentials. Here, we show, by using direct patchclamp recordings from presynaptic hippocampal mossy fiber boutons, that axons transmit analog signals in addition to action potentials. Excitatory presynaptic potentials result from subthreshold dendritic synaptic inputs, which propagate several hundreds of micrometers along the axon and modulate action potential-evoked transmitter release at the mossy fiber-CA3 synapse. This combined analog and action potential coding represents an additional mechanism for information transmission in a major hippocampal pathway.
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Affiliation(s)
- Henrik Alle
- Independent Hertie Research Group, Max Planck Institute for Brain Research, D-60528 Frankfurt, Germany
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22
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Bischofberger J, Geiger JRP, Jonas P. Timing and efficacy of Ca2+ channel activation in hippocampal mossy fiber boutons. J Neurosci 2002; 22:10593-602. [PMID: 12486151 PMCID: PMC6758411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023] Open
Abstract
The presynaptic Ca2+ signal is a key determinant of transmitter release at chemical synapses. In cortical synaptic terminals, however, little is known about the kinetic properties of the presynaptic Ca2+ channels. To investigate the timing and magnitude of the presynaptic Ca2+ inflow, we performed whole-cell patch-clamp recordings from mossy fiber boutons (MFBs) in rat hippocampus. MFBs showed large high-voltage-activated Ca(2+) currents, with a maximal amplitude of approximately 100 pA at a membrane potential of 0 mV. Both activation and deactivation were fast, with time constants in the submillisecond range at a temperature of approximately 23 degrees C. An MFB action potential (AP) applied as a voltage-clamp command evoked a transient Ca2+ current with an average amplitude of approximately 170 pA and a half-duration of 580 microsec. A prepulse to +40 mV had only minimal effects on the AP-evoked Ca2+ current, indicating that presynaptic APs open the voltage-gated Ca2+ channels very effectively. On the basis of the experimental data, we developed a kinetic model with four closed states and one open state, linked by voltage-dependent rate constants. Simulations of the Ca2+ current could reproduce the experimental data, including the large amplitude and rapid time course of the current evoked by MFB APs. Furthermore, the simulations indicate that the shape of the presynaptic AP and the gating kinetics of the Ca2+ channels are tuned to produce a maximal Ca2+ influx during a minimal period of time. The precise timing and high efficacy of Ca2+ channel activation at this cortical glutamatergic synapse may be important for synchronous transmitter release and temporal information processing.
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Hefft S, Kraushaar U, Geiger JRP, Jonas P. Presynaptic short-term depression is maintained during regulation of transmitter release at a GABAergic synapse in rat hippocampus. J Physiol 2002; 539:201-8. [PMID: 11850513 PMCID: PMC2290140 DOI: 10.1113/jphysiol.2001.013455] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
To examine possible interactions between fast depression and modulation of inhibitory synaptic transmission in the hippocampus, we recorded from pairs of synaptically connected basket cells (BCs) and granule cells (GCs) in the dentate gyrus of rat brain slices at 34 degrees C. Multiple-pulse depression (MPD) was examined in trains of 5 or 10 inhibitory postsynaptic currents (IPSCs) evoked at frequencies of 10-100 Hz under several conditions that inhibit transmitter release: block of voltage-dependent Ca2+ channels by Cd2+ (10 microM), activation of gamma-amino-butyric acid type B receptors (GABA(B)Rs) by baclofen (10 microM) and activation of muscarinic acetylcholine receptors (mAchRs) by carbachol (2 microM). All manipulations led to a substantial inhibition of synaptic transmission, reducing the amplitude of the first IPSC in the train (IPSC1) by 72%, 61% and 29%, respectively. However, MPD was largely preserved under these conditions (0.34 in control versus 0.31, 0.50 and 0.47 in the respective conditions at 50 Hz). Similarly, a theta burst stimulation (TBS) protocol reduced IPSC1 by 54%, but left MPD unchanged (0.40 in control and 0.39 during TBS). Analysis of both fractions of transmission failures and coefficients of variation (CV) of IPSC peak amplitudes suggested that MPD had a presynaptic expression site, independent of release probability. In conclusion, different types of presynaptic modulation of inhibitory synaptic transmission converge on a reduction of synaptic strength, while short-term dynamics are largely unchanged.
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Affiliation(s)
- Stefan Hefft
- Physiologisches Institut der Universität Freiburg, Hermann-Herder-Str. 7, D-79104 Freiburg, Germany
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Geiger JRP, Bischofberger J, Vida I, Fröbe U, Pfitzinger S, Weber HJ, Haverkampf K, Jonas P. Patch-clamp recording in brain slices with improved slicer technology. Pflugers Arch 2002; 443:491-501. [PMID: 11810221 DOI: 10.1007/s00424-001-0735-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2001] [Revised: 06/01/2001] [Accepted: 09/12/2001] [Indexed: 10/27/2022]
Abstract
The use of advanced patch-clamp recording techniques in brain slices, such as simultaneous recording from multiple neurons and recording from dendrites or presynaptic terminals, demands slices of the highest quality. In this context the mechanics of the tissue slicer are an important factor. Ideally, a tissue slicer should generate large-amplitude and high-frequency movements of the cutting blade in a horizontal axis, with minimal vibrations in the vertical axis. We developed a vibroslicer that fulfils these in part conflicting requirements. The oscillator is a permanent-magnet-coil-leaf-spring system. Using an auto-resonant mechano-electrical feedback circuit, large horizontal oscillations (up to 3 mm peak-to-peak) with high frequency ( approximately 90 Hz) are generated. To minimize vertical vibrations, an adjustment mechanism was employed that allowed alignment of the cutting edge of the blade with the major axis of the oscillation. A vibroprobe device was used to monitor vertical vibrations during adjustment. The system is based on the shading of the light path between a light-emitting diode (LED) and a photodiode. Vibroprobe monitoring revealed that the vibroslicer, after appropriate adjustment, generated vertical vibrations of <1 microm, significantly less than many commercial tissue slicers. Light- and electron-microscopic analysis of surface layers of slices cut with the vibroslicer showed that cellular elements, dendritic processes and presynaptic terminals are well preserved under these conditions, as required for patch-clamp recording from these structures.
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Affiliation(s)
- J R P Geiger
- Physiologisches Institut der Universität Freiburg, Abteilung I, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany
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