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Torres DB, Lopes A, Rodrigues AJ, Ventura-Silva AP, Sousa N, Gontijo JAR, Boer PA, Lopes MG. Early morphological and neurochemical changes of the bed nucleus of stria terminalis (BNST) in gestational protein-restricted male offspring. Nutr Neurosci 2024:1-19. [PMID: 38576309 DOI: 10.1080/1028415x.2024.2320498] [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: 04/06/2024]
Abstract
BACKGROUND The bed nucleus of the stria terminalis (BNST) is a structure with a peculiar neurochemical composition involved in modulating anxietylike behavior and fear. AIM The present study investigated the effects on the BNST neurochemical composition and neuronal structure in critical moments of the postnatal period in gestational protein-restricted male rats' offspring. METHODS Dams were maintained during the pregnancy on isocaloric rodent laboratory chow with standard protein content [NP, 17%] or low protein content [LP, 6%]. BNST from male NP and age-matched LP offspring was studied using the isotropic fractionator method, Neuronal 3D reconstruction, dendritic-tree analysis, blotting analysis, and high-performance liquid chromatography. RESULTS Serum corticosterone levels were higher in male LP offspring than NP rats in 14-day-old offspring, without any difference in 7-day-old progeny. The BNST total cell number and anterodorsal BNST division volume in LP progeny were significantly reduced on the 14th postnatal day compared with NP offspring. The BNST HPLC analysis from 7 days-old LP revealed increased norepinephrine levels compared to NP progeny. The BNST blot analysis from 7-day-old LP revealed reduced levels of GR and BDNF associated with enhanced CRF1 expression compared to NP offspring. 14-day-old LP offspring showed reduced expression of MR and 5HT1A associated with decreased DOPAC and DOPA turnover levels relative to NP rats. In Conclusion, the BNST cellular and neurochemical changes may represent adaptation during development in response to elevated fetal exposure to maternal corticosteroid levels. In this way, gestational malnutrition alters the BNST content and structure and contributes to already-known behavioral changes.
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Affiliation(s)
- D B Torres
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Internal Medicine Department, School of Medicine, State University of Campinas, Campinas, Brazil
| | - A Lopes
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Internal Medicine Department, School of Medicine, State University of Campinas, Campinas, Brazil
| | - A J Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - A P Ventura-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - N Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - J A R Gontijo
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Internal Medicine Department, School of Medicine, State University of Campinas, Campinas, Brazil
| | - P A Boer
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Internal Medicine Department, School of Medicine, State University of Campinas, Campinas, Brazil
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Xing W, de Lima AD, Voigt T. The Structural E/I Balance Constrains the Early Development of Cortical Network Activity. Front Cell Neurosci 2021; 15:687306. [PMID: 34349623 PMCID: PMC8326976 DOI: 10.3389/fncel.2021.687306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/17/2021] [Indexed: 01/03/2023] Open
Abstract
Neocortical networks have a characteristic constant ratio in the number of glutamatergic projection neurons (PN) and GABAergic interneurons (IN), and deviations in this ratio are often associated with developmental neuropathologies. Cultured networks with defined cellular content allowed us to ask if initial PN/IN ratios change the developmental population dynamics, and how different ratios impact the physiological excitatory/inhibitory (E/I) balance and the network activity development. During the first week in vitro, the IN content modulated PN numbers, increasing their proliferation in networks with higher IN proportions. The proportion of INs in each network set remained similar to the initial plating ratio during the 4 weeks cultivation period. Results from additional networks generated with more diverse cellular composition, including early-born GABA neurons, suggest that a GABA-dependent mechanism may decrease the survival of additional INs. A large variation of the PN/IN ratio did not change the balance between isolated spontaneous glutamatergic and GABAergic postsynaptic currents charge transfer (E/I balance) measured in PNs or INs. In contrast, the E/I balance of multisynaptic bursts reflected differences in IN content. Additionally, the spontaneous activity recorded by calcium imaging showed that higher IN ratios were associated with increased frequency of network bursts combined with a decrease of participating neurons per event. In the 4th week in vitro, bursting activity was stereotypically synchronized in networks with very few INs but was more desynchronized in networks with higher IN proportions. These results suggest that the E/I balance of isolated postsynaptic currents in single cells may be regulated independently of PN/IN proportions, but the network bursts E/I balance and the maturation of spontaneous network activity critically depends upon the structural PN/IN ratio.
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Affiliation(s)
- Wenxi Xing
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| | - Ana Dolabela de Lima
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| | - Thomas Voigt
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
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Gladkov A, Grinchuk O, Pigareva Y, Mukhina I, Kazantsev V, Pimashkin A. Theta rhythm-like bidirectional cycling dynamics of living neuronal networks in vitro. PLoS One 2018; 13:e0192468. [PMID: 29415033 PMCID: PMC5802926 DOI: 10.1371/journal.pone.0192468] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/24/2018] [Indexed: 12/12/2022] Open
Abstract
The phenomena of synchronization, rhythmogenesis and coherence observed in brain networks are believed to be a dynamic substrate for cognitive functions such as learning and memory. However, researchers are still debating whether the rhythmic activity emerges from the network morphology that developed during neurogenesis or as a result of neuronal dynamics achieved under certain conditions. In the present study, we observed self-organized spiking activity that converged to long, complex and rhythmically repeated superbursts in neural networks formed by mature hippocampal cultures with a high cellular density. The superburst lasted for tens of seconds and consisted of hundreds of short (50-100 ms) small bursts with a high spiking rate of 139.0 ± 78.6 Hz that is associated with high-frequency oscillations in the hippocampus. In turn, the bursting frequency represents a theta rhythm (11.2 ± 1.5 Hz). The distribution of spikes within the bursts was non-random, representing a set of well-defined spatio-temporal base patterns or motifs. The long superburst was classified into two types. Each type was associated with a unique direction of spike propagation and, hence, was encoded by a binary sequence with random switching between the two "functional" states. The precisely structured bidirectional rhythmic activity that developed in self-organizing cultured networks was quite similar to the activity observed in the in vivo experiments.
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Affiliation(s)
- Arseniy Gladkov
- Laboratory of Neuroengineering, Center of Translational Technologies, Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod, Russia
- Cell Technology Department, Central Research Laboratory, Nizhny Novgorod State Medical Academy, Nizhny Novgorod, Russia
| | - Oleg Grinchuk
- Information Science and Technology Department, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Yana Pigareva
- Laboratory of Neuroengineering, Center of Translational Technologies, Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod, Russia
| | - Irina Mukhina
- Laboratory of Neuroengineering, Center of Translational Technologies, Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod, Russia
- Cell Technology Department, Central Research Laboratory, Nizhny Novgorod State Medical Academy, Nizhny Novgorod, Russia
| | - Victor Kazantsev
- Laboratory of Neuroengineering, Center of Translational Technologies, Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod, Russia
| | - Alexey Pimashkin
- Laboratory of Neuroengineering, Center of Translational Technologies, Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod, Russia
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García-Álvarez I, Fernández-Mayoralas A, Moreno-Lillo S, Sánchez-Sierra M, Nieto-Sampedro M, Doncel-Pérez E. Inhibition of glial proliferation, promotion of axonal growth and myelin production by synthetic glycolipid: A new approach for spinal cord injury treatment. Restor Neurol Neurosci 2016; 33:895-910. [PMID: 26484699 DOI: 10.3233/rnn-150572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE After spinal cord injury (SCI) a glial scar is generated in the area affected that forms a barrier for axon growth and myelination, preventing functional recovery. Recently, we have described a synthetic glycolipid (IG20) that inhibited proliferation of human glioma cells. We show now that IG20 inhibited the proliferation of astrocytes and microglial cells, the principal cellular components of the glial scar, and promoting axonal outgrowth and myelin production in vitro. METHODS Glial cells were inhibited with IG20 (IC50≈10 μM) and studied by RT-PCR, Western Blotting, immunoprecipitation and fluorescence microscopy. Axonal outgrowth in dorsal root ganglia (DRG) and myelin production by oligodendrocytes were analyzed by immunocytochemistry. Adult rats were assayed in spinal cord contusion model and the recovery of treated animals (n = 6) and controls (n = 6) was followed. RESULTS The IG20 was localized in the cytosol of glial cells, forming a complex with RhoGDIα, a regulator of RhoGTPases. Treatment of astroglial cultures with IG20 increase the expression of BDNF receptor genes (TrkBT1, TrkB Full). IG20 reduced the astroglial marker GFAP, while increasing production of myelin basic protein in oligodendrocytes and promoted axonal outgrowth from DRG neurons. Local injection of IG20, near a spinal cord contusion, promoted the recovery of lesioned animals analyzed by BBB test (P < 0.05). CONCLUSIONS We propose that inhibition of astrocytes and microglia by IG20 could be diminished the glial scar formation, inducing the re-growth and myelination of axons, these elements constitute a new approach for SCI therapy.
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Affiliation(s)
- Isabel García-Álvarez
- Grupo de Química Neuro-regenerativa, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla La Mancha (SESCAM), Finca La Peraleda s/n, Toledo, Spain
| | | | - Sandra Moreno-Lillo
- Grupo de Química Neuro-regenerativa, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla La Mancha (SESCAM), Finca La Peraleda s/n, Toledo, Spain
| | - María Sánchez-Sierra
- Grupo de Química Neuro-regenerativa, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla La Mancha (SESCAM), Finca La Peraleda s/n, Toledo, Spain
| | | | - Ernesto Doncel-Pérez
- Grupo de Química Neuro-regenerativa, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla La Mancha (SESCAM), Finca La Peraleda s/n, Toledo, Spain
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Baltz T, Voigt T. Interaction of electrically evoked activity with intrinsic dynamics of cultured cortical networks with and without functional fast GABAergic synaptic transmission. Front Cell Neurosci 2015; 9:272. [PMID: 26236196 PMCID: PMC4505148 DOI: 10.3389/fncel.2015.00272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/02/2015] [Indexed: 11/23/2022] Open
Abstract
The modulation of neuronal activity by means of electrical stimulation is a successful therapeutic approach for patients suffering from a variety of central nervous system disorders. Prototypic networks formed by cultured cortical neurons represent an important model system to gain general insights in the input–output relationships of neuronal tissue. These networks undergo a multitude of developmental changes during their maturation, such as the excitatory–inhibitory shift of the neurotransmitter GABA. Very few studies have addressed how the output properties to a given stimulus change with ongoing development. Here, we investigate input–output relationships of cultured cortical networks by probing cultures with and without functional GABAAergic synaptic transmission with a set of stimulation paradigms at various stages of maturation. On the cellular level, low stimulation rates (<15 Hz) led to reliable neuronal responses; higher rates were increasingly ineffective. Similarly, on the network level, lowest stimulation rates (<0.1 Hz) lead to maximal output rates at all ages, indicating a network wide refractory period after each stimulus. In cultures aged 3 weeks and older, a gradual recovery of the network excitability within tens of milliseconds was in contrast to an abrupt recovery after about 5 s in cultures with absent GABAAergic synaptic transmission. In these GABA deficient cultures evoked responses were prolonged and had multiple discharges. Furthermore, the network excitability changed periodically, with a very slow spontaneous change of the overall network activity in the minute range, which was not observed in cultures with absent GABAAergic synaptic transmission. The electrically evoked activity of cultured cortical networks, therefore, is governed by at least two potentially interacting mechanisms: A refractory period in the order of a few seconds and a very slow GABA dependent oscillation of the network excitability.
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Affiliation(s)
- Thomas Baltz
- Institut für Physiologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Magdeburg Germany
| | - Thomas Voigt
- Institut für Physiologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Magdeburg Germany ; Center for Behavioral Brain Sciences, Magdeburg Germany
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Westerholz S, de Lima AD, Voigt T. Thyroid hormone-dependent development of early cortical networks: temporal specificity and the contribution of trkB and mTOR pathways. Front Cell Neurosci 2013; 7:121. [PMID: 23964198 PMCID: PMC3734363 DOI: 10.3389/fncel.2013.00121] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/10/2013] [Indexed: 11/17/2022] Open
Abstract
Early in neocortical network development, triiodothyronine (T3) promotes GABAergic neurons' population increase, their somatic growth and the formation of GABAergic synapses. In the presence of T3, GABAergic interneurons form longer axons and conspicuous axonal arborizations, with an increased number of putative synaptic boutons. Here we show that the increased GABAergic axonal growth is positively correlated with the proximity to non-GABAergic neurons (non-GABA). A differential innervation emerges from a T3-dependent decrease of axonal length in fields with low density of neuronal cell bodies, combined with an increased bouton formation in fields with high density of neuronal somata. T3 addition to deprived networks after the first 2 weeks of development did not rescue deficits in the GABAergic synaptic bouton distribution, or in the frequency and duration of spontaneous bursts. During the critical 2-week-period, GABAergic signaling is depolarizing as revealed by calcium imaging experiments. Interestingly, T3 enhanced the expression of the potassium-chloride cotransporter 2 (KCC2), and accelerated the developmental shift from depolarizing to hyperpolarizing GABAergic signaling in non-GABA. The T3-related increase of spontaneous network activity was remarkably reduced after blockade of either tropomyosin-receptor kinase B (trkB) or mammalian target of rapamycin (mTOR) pathways. T3-dependent increase in GABAergic neurons' soma size was mediated mainly by mTOR signaling. Conversely, the T3-dependent selective increase of GABAergic boutons near non-GABAergic cell bodies is mediated by trkB signaling only. Both trkB and mTOR signaling mediate T3-dependent reduction of the GABAergic axon extension. The circuitry context is relevant for the interaction between T3 and trkB signaling, but not for the interactions between T3 and mTOR signaling.
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Affiliation(s)
- Sören Westerholz
- Institute of Physiology, Otto-von-Guericke University Magdeburg, Germany
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7
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Baltz T, Herzog A, Voigt T. Slow oscillating population activity in developing cortical networks: models and experimental results. J Neurophysiol 2011; 106:1500-14. [PMID: 21697440 DOI: 10.1152/jn.00889.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During early development neuronal networks express slow oscillating synchronized activity. The activity can be driven by several, not necessarily mutually exclusive, mechanisms. Each mechanism might have distinctive consequences for the phenomenology, formation, or sustainment of the early activity pattern. Here we study the emergence of the oscillatory activity in three computational models and multisite extracellular recordings that we obtained from developing cortical networks in vitro. The modeled networks consist of leaky integrate-and-fire neurons with adaptation coupled via depressing synapses, which were driven by neurons that are intrinsically bursting, intrinsically random spiking, or driven by spontaneous synaptic activity. The activity of model networks driven by intrinsically bursting cells best matched the phenomenology of 1-wk-old cultures, in which early oscillatory activity has just begun. Intrinsically bursting neurons were present in cortical cultures, but we found them only in those cultures that were younger than 3 wk in vitro. On the other hand, synaptically dependent random spiking was highest after 3 wk in vitro. In conclusion, model networks driven by intrinsically bursting cells show a good approximation of the emergent recurrent population activity in young networks, whereas the activity of more mature networks seems to be better explained by spontaneous synaptic activity. Moreover, similar to previous experimental observations, distributed stimulation in the model was more effective in suppressing population bursts than repeated stimulation of the same neurons. This observation can be explained by an effective depression of a larger fraction of synapses by distributed stimulation.
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Affiliation(s)
- Thomas Baltz
- Institute of Physiology, Otto-von-Guericke-University, Magdeburg, Germany
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Modeling of Neuronal Growth In Vitro: Comparison of Simulation Tools NETMORPH and CX3D. EURASIP JOURNAL ON BIOINFORMATICS & SYSTEMS BIOLOGY 2011; 2011:616382. [PMID: 21436988 DOI: 10.1155/2011/616382] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 01/13/2011] [Indexed: 11/17/2022]
Abstract
We simulate the growth of neuronal networks using the two recently published tools, NETMORPH and CX3D. The goals of the work are (1) to examine and compare the simulation tools, (2) to construct a model of growth of neocortical cultures, and (3) to characterize the changes in network connectivity during growth, using standard graph theoretic methods. Parameters for the neocortical culture are chosen after consulting both the experimental and the computational work presented in the literature. The first (three) weeks in culture are known to be a time of development of extensive dendritic and axonal arbors and establishment of synaptic connections between the neurons. We simulate the growth of networks from day 1 to day 21. It is shown that for the properly selected parameters, the simulators can reproduce the experimentally obtained connectivity. The selected graph theoretic methods can capture the structural changes during growth.
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Baltz T, de Lima AD, Voigt T. Contribution of GABAergic interneurons to the development of spontaneous activity patterns in cultured neocortical networks. Front Cell Neurosci 2010; 4:15. [PMID: 20617185 PMCID: PMC2896208 DOI: 10.3389/fncel.2010.00015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 04/16/2010] [Indexed: 11/23/2022] Open
Abstract
Periodic synchronized events are a hallmark feature of developing neuronal networks and are assumed to be crucial for the maturation of the neuronal circuitry. In the developing neocortex, the early network oscillations coincide with an excitatory action of the neurotransmitter gamma-aminobutyric acid (GABA). A relationship between the emerging inhibitory action of GABA and the gradual disappearance of early synchronized network activity has been previously suggested. Therefore we investigate the interplay between the action of GABA and spontaneous activity in cultured networks of the lateral or dorsal embryonic rat neocortex, which show considerable difference in the content of GABAergic neurons. Here we present the results of long-term monitoring of spontaneous electrical activity of cultured networks growing on microelectrode arrays and the time course of changes in GABA action using calcium imaging. All cultures studied displayed stereotyped synchronized burst events at the end of the first week in vitro. As the GABAA depolarizing action decreases, naturally or after bumetanide treatment, network activity in lateral cortex cultures changed from stereotypic bursting to more clustered and asynchronous activity patterns. Dorsal cortex cultures and cultures lacking GABAA-receptor mediated synaptic transmission, retained an immature synchronous firing pattern, but developed prominent intraburst oscillations (∼3–10 Hz). Large, mostly parvalbumin positive, GABAergic neurons dominate the GABAergic population in lateral cortex cultures. These large interneurons were virtually absent in dorsal cortex cultures. Based on these results, we suggest that the richly interconnected large GABAergic neurons contribute to desynchronize and temporally differentiate the spontaneous activity of cultured cortical networks.
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Affiliation(s)
- Thomas Baltz
- Institute of Physiology, Otto-von-Guericke-University Magdeburg Magdeburg, Germany
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10
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Regulation of early spontaneous network activity and GABAergic neurons development by thyroid hormone. Neuroscience 2010; 168:573-89. [DOI: 10.1016/j.neuroscience.2010.03.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 11/21/2022]
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de Lima AD, Gieseler A, Voigt T. Relationship between GABAergic interneurons migration and early neocortical network activity. Dev Neurobiol 2009; 69:105-23. [PMID: 19086030 DOI: 10.1002/dneu.20696] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Available evidence converges to suggest that during the early development of the cerebral cortex, the emergence of the spontaneous network activity chronologically overlap with the end of the cell migration period in the developing cortex. We approached the functional regulation of neuronal migration in a culture model of neocortical networks, using time lapses to detect migratory movements, calcium-imaging to assess the activity of migratory neurons, and immunocytochemical methods to identify the migratory cells retrospectively. In cell cultures, early physiological development and cell migration are reproduced at a local network level, thus allowing the study of the interrelationships between cell migration and network development independent of the topographical complexity. Neurons migrate at least until 12 days in vitro and GABAergic neurons migrate faster compared with non-GABAergic neurons. A decline of migratory activity was coincident with the development of spontaneous synchronous network activity. Migrating interneurons did not participate in synchronous network activity, but interneurons that ended cell migration during observation time frequently engaged in synchronous activity within less than an hour. Application of GABA(A) and ionotropic glutamate receptor antagonists significantly increased the number of migrating GABAergic neurons without changing the dynamics of the migratory movements. Thus, neurotransmitters released by early network activity might favor the termination of neuronal migration. These results reinforce the idea that network activity plays an important role in the development of late-born GABAergic cells.
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Affiliation(s)
- Ana D de Lima
- Developmental Physiology, Institute of Physiology, Otto-von-Guericke University, 39120 Magdeburg, Germany
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12
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Developmental downregulation of GABAergic drive parallels formation of functional synapses in cultured mouse neocortical networks. Dev Neurobiol 2008; 68:934-49. [DOI: 10.1002/dneu.20632] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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de Lima AD, Lima BD, Voigt T. Earliest spontaneous activity differentially regulates neocortical GABAergic interneuron subpopulations. Eur J Neurosci 2007; 25:1-16. [PMID: 17241262 DOI: 10.1111/j.1460-9568.2006.05251.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although less than one quarter of all neurons in the cerebral cortex are GABAergic, these neurons are morphologically diverse and their physiological complexity decisively moulds the network physiology. An important question is how different subpopulations of GABAergic neurons are regulated numerically during development. In rat neocortical cultures, neuronal precursors continue to divide, generating both GABAergic and non-GABAergic neurons. In vitro generated GABAergic neurons form a population of uniquely small, mostly fusiform neurons that differ in size and morphology from older, in situ generated, large stellate GABAergic neurons. In a large series of experiments we investigated the impact of neuronal activity on the development of these two subpopulations of GABA interneurons present in cortical networks during the first 2 weeks in vitro. Here we show that a moderate increase in the generation of GABAergic neurons was achieved by blocking activity with tetrodotoxin, indicating that intrinsic spontaneous activity inhibits GABAergic neurogenesis in culture. Antagonists to ionotropic glutamate receptor and/or GABA(A) receptor did not significantly alter GABAergic generation but agonists to these receptors showed a time-sensitive regulation of the size of small and large GABAergic neuronal subpopulations. Further, our results indicate that alterations of cell generation by activity manipulations might be overwritten by later activity effects on the survival of GABAergic cell populations.
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Affiliation(s)
- Ana D de Lima
- Otto-von-Guericke University, Department of Developmental Physiology, Institute of Physiology, Leipziger Strasse 44, D-39120 Magdeburg, Germany
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Voigt T, Opitz T, de Lima AD. Activation of early silent synapses by spontaneous synchronous network activity limits the range of neocortical connections. J Neurosci 2006; 25:4605-15. [PMID: 15872108 PMCID: PMC6725027 DOI: 10.1523/jneurosci.3803-04.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During the early development of neocortical networks, many glutamatergic synapses lack AMPA receptors and are physiologically silent. We show in neocortical cultures that spontaneous synchronous network activity is able to convert silent synapses to active synapses by the incorporation of AMPA receptors into synaptic complexes throughout the network within a few minutes. To test the effect of synaptic activation on the connectivity of neuronal populations, we created separated neuronal networks that could innervate each other. We allowed outgrowing axons to invade the neighboring network either before or after the onset of synchronous network activity. In the first case, both subnetworks connected to each other and synchronized their activity, whereas in the second case, axonal connections failed to form and network activity did not synchronize between compartments. We conclude that early spontaneous synchronous network activity triggers a global AMPAfication of immature synapses, which in turn prevents later-arriving axons from forming afferent connections. This activity-dependent process may set the range of corticocortical connections during early network development before experience-dependent mechanisms begin elaborating the mature layout of the neocortical connections and modules.
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Affiliation(s)
- Thomas Voigt
- Department of Developmental Physiology, Otto-von-Guericke University, Institute of Physiology, 39120 Magdeburg, Germany.
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Rouach N, Koulakoff A, Giaume C. Neurons set the tone of gap junctional communication in astrocytic networks. Neurochem Int 2004; 45:265-72. [PMID: 15145542 DOI: 10.1016/j.neuint.2003.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2003] [Accepted: 07/31/2003] [Indexed: 11/20/2022]
Abstract
A number of studies have contributed to demonstrate that neurons and astrocytes tightly and actively interact. Indeed, the presence of astrocytes in neuronal cultures increases the number of synapses and their efficiency, and thanks to enzymatic and uptake processes, astrocytes play a role in neuroprotection. A typical feature of astrocytes is that they establish cell-cell communication in vitro, as well as in situ, through intercellular channels forming specialized membrane areas defined as gap junctions. These channels are composed of junctional proteins termed connexins (Cxs): in astrocytes connexin 43 (Cx43) and 30 (Cx30) have been shown to prevail. Several recent works indicate that gap junctional communication (GJC) and/or connexin expression in astrocytes are controlled by neurons. Altogether, these observations lead to the concept that neuronal and astrocytic networks interact through mutual setting of their respective mode of communication and that astrocyte gap junctions represent a target in neuroglial interaction.
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Affiliation(s)
- Nathalie Rouach
- INSERM U114, Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
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de Lima AD, Opitz T, Voigt T. Irreversible loss of a subpopulation of cortical interneurons in the absence of glutamatergic network activity. Eur J Neurosci 2004; 19:2931-43. [PMID: 15182300 DOI: 10.1111/j.0953-816x.2004.03403.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the cerebral cortex of mammals, gamma-aminobutyric acid (GABA)ergic neurons represent 15-25% of all neurons, depending on the species and area being examined. Because converging evidence suggests that activity may play an important role in the neuritic maturation and synaptic function of GABAergic neurons, it is feasible that activity plays a role in the regulation of the proportion of GABAergic neurons. Here we provide direct evidence that early in cortical development activity blockade may deplete the network of a subpopulation of GABA immunoreactive neurons characterized by their small size and late generation in vitro. In a period of time coinciding with the emergence of synchronous network activity, the survival and morphological differentiation of GABAergic neurons was influenced by long-term blockade of synaptic activity. While GABA(A) receptor antagonists had a minor promoting effect on interneuronal survival during the second week in vitro, antagonists of ionotropic glutamate receptors strongly impaired survival and differentiation of immature GABAergic interneurons. Interneuronal loss was more severe when N-methyl-D-aspartate receptors were blocked than after blockade of alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA)/kainate receptors. The decrease in the density of GABAergic neurons was irreversible, but could be prevented by the simultaneous addition of brain-derived neurotrophic factor (BDNF). These results suggest that there is a narrow time window during neocortical development when glutamatergic activity, and specially NMDA receptor stimulation, is crucial to assure survival and maturation of a subpopulation of late developing GABAergic interneurons.
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Affiliation(s)
- Ana Dolabela de Lima
- Otto-von-Guericke Universität, Medizinische Fakultät, Institut für Physiologie, 39120 Magdeburg, Germany.
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Opitz T, De Lima AD, Voigt T. Spontaneous development of synchronous oscillatory activity during maturation of cortical networks in vitro. J Neurophysiol 2002; 88:2196-206. [PMID: 12424261 DOI: 10.1152/jn.00316.2002] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent studies have focused attention on mechanisms of spontaneous large-scale wavelike activity during early development of the neocortex. In this study, we describe and characterize synchronous neuronal activity that occurs in cultured cortical networks naturally without pharmacological intervention. The synchronous activity that can be detected by means of Fluo-3 fluorescence imaging starts to develop at the beginning of the second week in culture and eventually includes the entire neuronal population about 1 wk later. A synchronous increase of [Ca(2+)](i) in the neuronal population is associated with a burst of action potentials riding on a long-lasting depolarization recorded in a single cell. It is suggested that this depolarization results directly from synaptic current, which was comprised of at least three different components mediated by AMPA, N-methyl-D-aspartate (NMDA), and GABA(A) receptors. We never observed a gradually depolarizing pacemaker potential and found no evidence for a change of excitability during inter-burst periods. However, we found evidence for a period of synaptic depression after bursts. Network excitability recovers gradually over seconds from this depression that can explain the episodic nature of spontaneous network activity. Using pharmacological manipulation to investigate the propagation of activity in the network, we show that synchronous network activity depends on both glutamatergic and GABA(A)ergic neurotransmission during a brief period. Reversal potential of GABA(A) receptor-mediated current was found to be significantly more positive than resting membrane potential both at 1 and 2 wk in culture, suggesting depolarizing action of GABA. However, in cultures older than 2 wk, inhibition of GABA(A) receptors does not result in block of synchronous network activity but in modulation of burst width and frequency.
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Affiliation(s)
- Thoralf Opitz
- Department of Developmental Physiology, Institute for Physiology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
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Hans G, Moonen G, Rigo JM. Modulation of neuronal survival and excitability by an astroglia-derived factor. JOURNAL OF PHYSIOLOGY, PARIS 2002; 96:323-8. [PMID: 12445913 DOI: 10.1016/s0928-4257(02)00023-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We summarize here currently available data related to an astroglia-secreted factor that induces neuronal apoptosis and behaves as an inhibitor of ionotropic inhibitory GABA(A) and glycine receptors.
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Affiliation(s)
- Grégory Hans
- Center for Cellular and Molecular Neuroscience, University of Liège, 17 place Delcour, B-4020 Liège, Belgium
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Abstract
Neurons dissociated from embryonic cerebral rat cortex form a differentiated network of synaptic connections and develop synchronous oscillatory network activity with the beginning of the second week in culture. During an initial phase lasting 3-4 d, synchronous calcium transients can be blocked completely by either CNQX or bicuculline, showing that both glutamatergic and GABAergic neurons are required for the generation of this form of activity. By manipulating dissociation and growth conditions, cultures containing different populations of GABAergic neurons were obtained. These cultures revealed that a distinct population of large GABAergic neurons is a key element in the generation of synchronous oscillatory network activity. A minimal number of two large GABAergic neurons per square millimeter are required for the occurrence of synchronous activity. Changes in the density of all other types of GABAergic or non-GABAergic neurons has no influence on the synchronous activity. Electron microscopic analysis shows that the large GABAergic neurons form an interconnected network. Exceptionally high somatodendritic innervation and extended axonal arborization enable these neurons to collect electric network activity and to distribute it effectively throughout the neuronal network. Additional experiments indicated that most neurons developing in culture to large GABAergic neurons are derived from the primordial plexiform layer and reside in the subplate at the time of birth. We suggest that they function as an integrating element that synchronizes neuronal activity during early cortical development by collecting incoming extrinsic and intrinsic signals and distributing them effectively throughout the developing cortical plate.
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Rouach N, Giaume C. Connexins and gap junctional communication in astrocytes are targets for neuroglial interaction. PROGRESS IN BRAIN RESEARCH 2001; 132:203-14. [PMID: 11544989 DOI: 10.1016/s0079-6123(01)32077-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- N Rouach
- INSERM U114, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris, France
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