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Vafadari B, Oku Y, Tacke C, Harb A, Hülsmann S. In-vivo optogenetic identification and electrophysiology of glycinergic neurons in pre-Bötzinger complex of mice. Respir Physiol Neurobiol 2024; 320:104188. [PMID: 37939866 DOI: 10.1016/j.resp.2023.104188] [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: 09/15/2023] [Revised: 11/01/2023] [Accepted: 11/06/2023] [Indexed: 11/10/2023]
Abstract
Breathing requires distinct patterns of neuronal activity in the brainstem. The most critical part of the neuronal network responsible for respiratory rhythm generation is the preBötzinger Complex (preBötC), located in the ventrolateral medulla. This area contains both rhythmogenic glutamatergic neurons and also a high number of inhibitory neurons. Here, we aimed to analyze the activity of glycinergic neurons in the preBötC in anesthetized mice. To identify inhibitory neurons, we used a transgenic mouse line that allows expression of Channelrhodopsin 2 in glycinergic neurons. Using juxtacellular recordings and optogenetic activation via a single recording electrode, we were able to identify neurons as inhibitory and define their activity pattern in relation to the breathing rhythm. We could show that the activity pattern of glycinergic respiratory neurons in the preBötC was heterogeneous. Interestingly, only a minority of the identified glycinergic neurons showed a clear phase-locked activity pattern in every respiratory cycle. Taken together, we could show that neuron identification is possible by a combination of juxtacellular recordings and optogenetic activation via a single recording electrode.
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Affiliation(s)
- Behnam Vafadari
- Department of Anesthesiology, University Medical Center, Georg-August University, Göttingen, Germany
| | - Yoshitaka Oku
- Division of Physiome, Department of Physiology, Hyogo Medical University, Nishinomiya, Japan
| | - Charlotte Tacke
- Department of Anesthesiology, University Medical Center, Georg-August University, Göttingen, Germany
| | - Ali Harb
- Department of Anesthesiology, University Medical Center, Georg-August University, Göttingen, Germany
| | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center, Georg-August University, Göttingen, Germany.
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Khan A, Markus MA, Svetlove A, Hülsmann S, Alves F, Dullin C. Longitudinal x-ray based lung function measurement for monitoring Nintedanib treatment response in a mouse model of lung fibrosis. Sci Rep 2023; 13:18637. [PMID: 37903864 PMCID: PMC10616088 DOI: 10.1038/s41598-023-45305-x] [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: 06/02/2023] [Accepted: 10/18/2023] [Indexed: 11/01/2023] Open
Abstract
Lung fibrosis (LF) is a chronic progressive, incurable, and debilitating condition of the lung, which is associated with different lung disease. Treatment options are still sparse. Nintedanib, an oral tyrosine kinase inhibitor, significantly slows the LF progression. However, there is a strong need of further research and the development of novel therapies. In this study, we used a correlative set-up that combines X-ray based lung function (XLF) with microCT and whole body plethysmography (WBP) for a comprehensive functional and structural evaluation of lung fibrosis (LF) as well as for monitoring response to orally administered Nintedanib in the mouse model of bleomycin induced LF. The decline in lung function as early as one week after intratracheal bleomycin instillation was reliably detected by XLF, revealing the lowest decay rate in the LF mice compared to healthy ones. Simultaneously performed microCT and WBP measurements corroborated XLF findings by exhibiting reduced lung volume [Formula: see text] and tidal volume [Formula: see text]. In LF mice XLF also revealed profound improvement in lung function one week after Nintedanib treatment. This positive response to Nintedanib therapy was further substantiated by microCT and WBP measurements which also showed significantly improved [Formula: see text] and [Formula: see text] in the Nintedanib treated mice. By comparing the XLF data to structural features assessing the extent of fibrosis obtained by ex-vivo high-resolution synchrotron radiation-based imaging and classical histology we demonstrate that: (1) a simple low dose x-ray measurement like XLF is sensitive enough to pick up treatment response, (2) Nintedanib treatment successfully improved lung function in a bleomycin induced LF mouse model and (3) differences between the fully restored lung function and the partially reduced fibrotic burden compared to healthy and untreated mice. The presented analysis pipeline underlines the importance of a combined functional and anatomical readout to reliably measure treatment response and could easily be adapted to other preclinical lung disease models.
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Affiliation(s)
- Amara Khan
- Translational Molecular Imaging, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - M Andrea Markus
- Translational Molecular Imaging, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Angelika Svetlove
- Translational Molecular Imaging, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Göttingen, Germany
| | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center, Göttingen, Germany
| | - Frauke Alves
- Translational Molecular Imaging, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Göttingen, Germany
- Clinic of Hematology and Medical Oncology, University Medical Center, Göttingen, Germany
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany
| | - Christian Dullin
- Translational Molecular Imaging, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany.
- Institute for Diagnostic and Interventional Radiology, University Hospital, Heidelberg, Germany.
- Translational Lung Research Center, Heidelberg, Germany.
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Tacke C, Bischoff AM, Harb A, Vafadari B, Hülsmann S. Fiber optical imaging of astroglial calcium signaling in the respiratory network in the working heart brainstem preparation. Front Physiol 2023; 14:1237376. [PMID: 37693007 PMCID: PMC10484401 DOI: 10.3389/fphys.2023.1237376] [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: 06/09/2023] [Accepted: 08/10/2023] [Indexed: 09/12/2023] Open
Abstract
The neuronal activity in the respiratory network strongly depends on a variety of different neuromodulators. Given the essential role of astrocytes in stabilizing respiratory network activity generated by neurons in the preBötzinger complex (preBötC), our aim was to investigate astrocytic calcium signaling in the working heart brainstem preparation using fiber-optical imaging. By using transgenic mice that express GCaMP6s specifically in astrocytes, we successfully recorded astrocytic calcium signals in response to norepinephrine from individual astrocytes.
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Affiliation(s)
| | | | | | | | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
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Vafadari B, Tacke C, Harb A, Grützner AA, Hülsmann S. Increase of breathing rate mediated by unilateral optogenetic inactivation of inhibitory neurons in the preBötzinger Complex in vivo. Respir Physiol Neurobiol 2023; 311:104032. [PMID: 36758781 DOI: 10.1016/j.resp.2023.104032] [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: 12/20/2022] [Revised: 01/26/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023]
Abstract
Brainstem neural circuits located in the preBötzinger complex (preBötC) and Bötzinger complex (BötC) play a critical role in the control of breathing. In this study, glycinergic preBötC and BötC neurons were inactivated with optogenetics in vivo using mice with Cre inducible expression of eNpHR3.0-EYFP. Unilateral inhibition of glycinergic neurons in the preBötC, and to a lower extend also in the BötC, led to a higher respiratory rate. It can be concluded that functional inactivation of inhibitory neurons leads to a disinhibition of preBötC excitatory neurons and thus an increase in the respiratory drive of the network.
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Affiliation(s)
- Behnam Vafadari
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany.
| | - Charlotte Tacke
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Ali Harb
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Anja-Annett Grützner
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
| | - Swen Hülsmann
- Department of Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany.
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Tacke C, Bischoff AM, Harb A, Vafadari B, Hülsmann S. Angiotensin II increases respiratory rhythmic activity in the preBötzinger complex without inducing astroglial calcium signaling. Front Cell Neurosci 2023; 17:1111263. [PMID: 36816850 PMCID: PMC9932970 DOI: 10.3389/fncel.2023.1111263] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Angiotensin II (Ang II) is the primary modulator of the renin-angiotensin system and has been widely studied for its effect on the cardiovascular system. While a few studies have also indicated an involvement of Ang II in the regulation of breathing, very little is known in this regard and its effect on brainstem respiratory regions such as the preBötzinger complex (preBötC), the kernel for inspiratory rhythm generation, has not been investigated yet. This study reports that Ang II temporarily increases phrenic nerve activity in the working heart-brainstem preparation, indicating higher central respiratory drive. Previous studies have shown that the carotid body is involved in mediating this effect and we revealed that the preBötC also plays a part, using acute slices of the brainstem. It appears that Ang II is increasing the respiratory drive in an AT1R-dependent manner by optimizing the interaction of inhibitory and excitatory neurons of the preBötC. Thus, Ang II-mediated effects on the preBötC are potentially involved in dysregulating breathing in patients with acute lung injury.
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Oke Y, Miwakeichi F, Oku Y, Hirrlinger J, Hülsmann S. Cell types and synchronous-activity patterns of inspiratory neurons in the preBötzinger complex of mouse medullary slices during early postnatal development. Sci Rep 2023; 13:586. [PMID: 36631589 PMCID: PMC9834223 DOI: 10.1038/s41598-023-27893-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
To examine whether and how the inspiratory neuronal network in the preBötzinger complex (preBötC) develops during the early postnatal period, we quantified the composition of the population of inspiratory neurons between postnatal day 1 (p1) and p10 by applying calcium imaging to medullary transverse slices in double-transgenic mice expressing fluorescent marker proteins. We found that putative excitatory and glycinergic neurons formed a majority of the population of inspiratory neurons, and the composition rates of these two inspiratory neurons inverted at p5-6. We also found that the activity patterns of these two types of inspiratory neurons became significantly well-synchronized with the inspiratory rhythmic bursting pattern in the preBötC within the first postnatal week. GABAergic and GABA-glycine cotransmitting inspiratory neurons formed only a small population just after birth, which almost disappeared until p10. In conclusion, the inspiratory neuronal network in the preBötC matures at the level of both neuronal population and neuronal activities during early postnatal development.
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Affiliation(s)
- Yoshihiko Oke
- Division of Physiome, Department of Physiology, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya, 663-8501, Japan.
| | - Fumikazu Miwakeichi
- grid.507381.80000 0001 1945 4756Department of Statistical Modeling, The Institute of Statistical Mathematics, 10-3, Midori-cho, Tachikawa, 190-0014 Japan ,grid.275033.00000 0004 1763 208XDepartment of Statistical Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies, Shounan-Kokusai-Mura, Hayama-cho, Miura, 240-0193 Japan
| | - Yoshitaka Oku
- grid.272264.70000 0000 9142 153XDivision of Physiome, Department of Physiology, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya, 663-8501 Japan
| | - Johannes Hirrlinger
- grid.9647.c0000 0004 7669 9786Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Liebigstraße 27, 04103 Leipzig, Germany ,grid.516369.eDepartment of Neurogenetics, Max Planck Institute for Multidisciplinary Science, Hermann-Rein-Straße 3, 37075 Göttingen, Germany
| | - Swen Hülsmann
- grid.411984.10000 0001 0482 5331Department of Anesthesiology, University Medical Center, Humboldtallee 23, 37073 Göttingen, Germany
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Svetlove A, Albers J, Hülsmann S, Markus MA, Zschüntzsch J, Alves F, Dullin C. Non-Invasive Optical Motion Tracking Allows Monitoring of Respiratory Dynamics in Dystrophin-Deficient Mice. Cells 2022; 11:cells11050918. [PMID: 35269540 PMCID: PMC8909479 DOI: 10.3390/cells11050918] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 02/08/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most common x-chromosomal inherited dystrophinopathy which leads to progressive muscle weakness and a premature death due to cardiorespiratory dysfunction. The mdx mouse lacks functional dystrophin protein and has a comparatively human-like diaphragm phenotype. To date, diaphragm function can only be inadequately mapped in preclinical studies and a simple reliable translatable method of tracking the severity of the disease still lacks. We aimed to establish a sensitive, reliable, harmless and easy way to assess the effects of respiratory muscle weakness and subsequent irregularity in breathing pattern. Optical respiratory dynamics tracking (ORDT) was developed utilising a camera to track the movement of paper markers placed on the thoracic-abdominal region of the mouse. ORDT successfully distinguished diseased mdx phenotype from healthy controls by measuring significantly higher expiration constants (k) in mdx mice compared to wildtype (wt), which were also observed in the established X-ray based lung function (XLF). In contrast to XLF, with ORDT we were able to distinguish distinct fast and slow expiratory phases. In mdx mice, a larger part of the expiratory marker displacement was achieved in this initial fast phase as compared to wt mice. This phenomenon could not be observed in the XLF measurements. We further validated the simplicity and reliability of our approach by demonstrating that it can be performed using free-hand smartphone acquisition. We conclude that ORDT has a great preclinical potential to monitor DMD and other neuromuscular diseases based on changes in the breathing patterns with the future possibility to track therapy response.
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Affiliation(s)
- Angelika Svetlove
- Translational Molecular Imaging, Max-Planck Institute for Multidisciplinary Sciences, City Campus, 37075 Göttingen, Germany; (A.S.); (M.A.M.); (F.A.)
| | - Jonas Albers
- X-ray Based Preclinical Imaging Technologies, Institute for Diagnostic and Interventional Radiology, University Medical Center, 37075 Göttingen, Germany;
| | - Swen Hülsmann
- Central Breathing Control, Clinic for Anesthesiology, University Medical Center, 37075 Göttingen, Germany;
| | - Marietta Andrea Markus
- Translational Molecular Imaging, Max-Planck Institute for Multidisciplinary Sciences, City Campus, 37075 Göttingen, Germany; (A.S.); (M.A.M.); (F.A.)
| | - Jana Zschüntzsch
- Neuromuscular Disease Research, Clinic for Neurology, University Medical Center, 37075 Göttingen, Germany;
| | - Frauke Alves
- Translational Molecular Imaging, Max-Planck Institute for Multidisciplinary Sciences, City Campus, 37075 Göttingen, Germany; (A.S.); (M.A.M.); (F.A.)
- X-ray Based Preclinical Imaging Technologies, Institute for Diagnostic and Interventional Radiology, University Medical Center, 37075 Göttingen, Germany;
- Clinic for Haematology and Medical Oncology, University Medical Center, 37075 Göttingen, Germany
- Multiscale Bioimaging—From Molecular Machines to Networks of Excitable Cells, Cluster of Excellence (MBExC), 37075 Göttingen, Germany
| | - Christian Dullin
- X-ray Based Preclinical Imaging Technologies, Institute for Diagnostic and Interventional Radiology, University Medical Center, 37075 Göttingen, Germany;
- Institute for Diagnostic and Interventional Radiology, University Hospital, 69120 Heidelberg, Germany
- Correspondence:
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Eulenburg V, Hülsmann S. Synergistic Control of Transmitter Turnover at Glycinergic Synapses by GlyT1, GlyT2, and ASC-1. Int J Mol Sci 2022; 23:ijms23052561. [PMID: 35269698 PMCID: PMC8909939 DOI: 10.3390/ijms23052561] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 01/25/2023] Open
Abstract
In addition to being involved in protein biosynthesis and metabolism, the amino acid glycine is the most important inhibitory neurotransmitter in caudal regions of the brain. These functions require a tight regulation of glycine concentration not only in the synaptic cleft, but also in various intracellular and extracellular compartments. This is achieved not only by confining the synthesis and degradation of glycine predominantly to the mitochondria, but also by the action of high-affinity large-capacity glycine transporters that mediate the transport of glycine across the membranes of presynaptic terminals or glial cells surrounding the synapses. Although most cells at glycine-dependent synapses express more than one transporter with high affinity for glycine, their synergistic functional interaction is only poorly understood. In this review, we summarize our current knowledge of the two high-affinity transporters for glycine, the sodium-dependent glycine transporters 1 (GlyT1; SLC6A9) and 2 (GlyT2; SLC6A5) and the alanine–serine–cysteine-1 transporter (Asc-1; SLC7A10).
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Affiliation(s)
- Volker Eulenburg
- Department for Anesthesiology and Intensive Care, Faculty of Medicine, University of Leipzig, Liebigstraße 20, D-04103 Leipzig, Germany
- Correspondence: (V.E.); (S.H.)
| | - Swen Hülsmann
- Department for Anesthesiology, University Medical Center, Georg-August University, Humboldtallee 23, D-37073 Göttingen, Germany
- Correspondence: (V.E.); (S.H.)
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Hülsmann S, Khan A, Hagos L, Hindermann M, Nägel T, Dullin C. Evaluation of a mechanical lung model to test small animal whole body plethysmography. Sci Rep 2021; 11:17099. [PMID: 34429449 PMCID: PMC8384843 DOI: 10.1038/s41598-021-96355-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 07/30/2021] [Indexed: 11/27/2022] Open
Abstract
Whole-body plethysmography (WBP) is an established method to determine physiological parameters and pathophysiological alteration of breathing in animals and animal models of a variety of diseases. Although frequently used, there is ongoing debate about what exactly is measured by whole-body-plethysmography and how reliable the data derived from this method are. Here, we designed an artificial lung model that enables a thorough evaluation of different predictions about and around whole-body plethysmography. Using our lung model, we confirmed that during WBP two components contribute to the pressure changes detected in the chamber: (1) the increase in the pressure due to heating and moistening of the air during inspiration, termed conditioning; (2) changes in the chamber pressure that depend on airway resistance. Both components overlap and contribute to the temporal pressure-profile measured in the chamber or across the wall of the chamber, respectively. Our data showed that a precise measurement of the breathing volume appears to be hindered by at least two factors: (1) the unknown relative contribution of each of these two components; (2) not only the air in the inspired volume is conditioned during inspiration, but also air within the residual volume and dead space that is recruited during inspiration. Moreover, our data suggest that the expiratory negative pressure peak that is used to determine the enhanced pause (Penh) parameter is not a measure for airway resistance as such but rather a consequence of the animal’s response to the airway resistance, using forced or active expiration to overcome the resistance by a higher thoracic pressure.
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Affiliation(s)
- Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany.
| | - Amara Khan
- Department of Translational Molecular Imaging, Max-Plank-Institute of Experimental Medicine, Göttingen, Germany
| | - Liya Hagos
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany
| | - Martin Hindermann
- Department of Clinical Neuroscience, Max-Plank-Institute of Experimental Medicine, Göttingen, Germany
| | - Torsten Nägel
- Institute of Neuro- and Sensory Physiology, University Medical Center, Göttingen, Germany
| | - Christian Dullin
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany.,Italian Synchrotron Light Source 'Elettra' Trieste, Trieste, Italy
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Khan A, Markus A, Rittmann T, Albers J, Alves F, Hülsmann S, Dullin C. Simple low dose radiography allows precise lung volume assessment in mice. Sci Rep 2021; 11:4163. [PMID: 33602964 PMCID: PMC7893164 DOI: 10.1038/s41598-021-83319-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/08/2021] [Indexed: 02/07/2023] Open
Abstract
X-ray based lung function (XLF) as a planar method uses dramatically less X-ray dose than computed tomography (CT) but so far lacked the ability to relate its parameters to pulmonary air volume. The purpose of this study was to calibrate the functional constituents of XLF that are biomedically decipherable and directly comparable to that of micro-CT and whole-body plethysmography (WBP). Here, we developed a unique set-up for simultaneous assessment of lung function and volume using XLF, micro-CT and WBP on healthy mice. Our results reveal a strong correlation of lung volumes obtained from radiographic XLF and micro-CT and demonstrate that XLF is superior to WBP in sensitivity and precision to assess lung volumes. Importantly, XLF measurement uses only a fraction of the radiation dose and acquisition time required for CT. Therefore, the redefined XLF approach is a promising tool for preclinical longitudinal studies with a substantial potential of clinical translation.
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Affiliation(s)
- Amara Khan
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Andrea Markus
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Thomas Rittmann
- 4th Physical Institute - Solids and Nanostructures, University of Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Jonas Albers
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Frauke Alves
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
- Clinic for Hematology and Medical Oncology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Christian Dullin
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany.
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
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Hülsmann S, Khabbazzadeh S, Meissner K, Quintel M. A Potential Role of the Renin-Angiotensin-System for Disturbances of Respiratory Chemosensitivity in Acute Respiratory Distress Syndrome and Severe Acute Respiratory Syndrome. Front Physiol 2021; 11:588248. [PMID: 33551831 PMCID: PMC7857271 DOI: 10.3389/fphys.2020.588248] [Citation(s) in RCA: 2] [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: 07/28/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) represents an acute diffuse inflammation of the lungs triggered by different causes, uniformly leading to a noncardiogenic pulmonary edema with inhomogeneous densities in lung X-ray and lung CT scan and acute hypoxemia. Edema formation results in "heavy" lungs, inducing loss of compliance and the need to spend more energy to "move" the lungs. Consequently, an ARDS patient, as long as the patient is breathing spontaneously, has an increased respiratory drive to ensure adequate oxygenation and CO2 removal. One would expect that, once the blood gases get back to "physiological" values, the respiratory drive would normalize and the breathing effort return to its initial status. However, in many ARDS patients, this is not the case; their respiratory drive appears to be upregulated and fully or at least partially detached from the blood gas status. Strikingly, similar alteration of the respiratory drive can be seen in patients suffering from SARS, especially SARS-Covid-19. We hypothesize that alterations of the renin-angiotensin-system (RAS) related to the pathophysiology of ARDS and SARS are involved in this dysregulation of chemosensitive control of breathing.
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Affiliation(s)
- Swen Hülsmann
- Universitätsmedizin Göttingen, Klinik für Anästhesiologie, Georg-August-Universität, Göttingen, Germany
| | - Sepideh Khabbazzadeh
- Universitätsmedizin Göttingen, Klinik für Anästhesiologie, Georg-August-Universität, Göttingen, Germany
| | - Konrad Meissner
- Universitätsmedizin Göttingen, Klinik für Anästhesiologie, Georg-August-Universität, Göttingen, Germany
| | - Michael Quintel
- Universitätsmedizin Göttingen, Klinik für Anästhesiologie, Georg-August-Universität, Göttingen, Germany
- DONAUISAR Klinikum Deggendorf, Deggendorf, Germany
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12
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Affiliation(s)
- Swen Hülsmann
- Universitätsmedizin Göttingen Klinik für Anästhesiologie Georg‐August‐Universität Göttingen Germany
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13
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Hirrlinger J, Marx G, Besser S, Sicker M, Köhler S, Hirrlinger PG, Wojcik SM, Eulenburg V, Winkler U, Hülsmann S. GABA-Glycine Cotransmitting Neurons in the Ventrolateral Medulla: Development and Functional Relevance for Breathing. Front Cell Neurosci 2019; 13:517. [PMID: 31803026 PMCID: PMC6877658 DOI: 10.3389/fncel.2019.00517] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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: 07/05/2019] [Accepted: 11/04/2019] [Indexed: 11/13/2022] Open
Abstract
Inhibitory neurons crucially contribute to shaping the breathing rhythm in the brain stem. These neurons use GABA or glycine as neurotransmitter; or co-release GABA and glycine. However, the developmental relationship between GABAergic, glycinergic and cotransmitting neurons, and the functional relevance of cotransmitting neurons has remained enigmatic. Transgenic mice expressing fluorescent markers or the split-Cre system in inhibitory neurons were developed to track the three different interneuron phenotypes. During late embryonic development, the majority of inhibitory neurons in the ventrolateral medulla are cotransmitting cells, most of which differentiate into GABAergic and glycinergic neurons around birth and around postnatal day 4, respectively. Functional inactivation of cotransmitting neurons revealed an increase of the number of respiratory pauses, the cycle-by-cycle variability, and the overall variability of breathing. In summary, the majority of cotransmitting neurons differentiate into GABAergic or glycinergic neurons within the first 2 weeks after birth and these neurons contribute to fine-tuning of the breathing pattern.
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Affiliation(s)
- Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Grit Marx
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Stefanie Besser
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Marit Sicker
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Susanne Köhler
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Petra G Hirrlinger
- Medizinisch-Experimentelles Zentrum, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Volker Eulenburg
- Department for Anesthesiology and Intensive Care Therapy, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Ulrike Winkler
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Swen Hülsmann
- Department of Anaesthesiology, University Medical Center, Georg-August University, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
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14
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Abstract
Respiratory neurobiology has been a lead discipline in the field of neuroscience for almost a century. Despite this, research studies on the fundamental synaptic and cellular processes underlying the generation and modulation of breathing movements suffered a significant decline during the last decade. We still believe that respiratory neurobiology is one of the most exciting and imperative fields of neuroscience. With the first white paper concerned with the central control of breathing, we want to celebrate the global importance of breathing research.
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Affiliation(s)
- T.E. Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH, USA,Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - M. Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Melbourne 3052, VIC, Australia,Corresponding author. (M. Dutschmann)
| | - J.L Feldman
- Systems Neurobiology Laboratory, Department of Neurobiology, David Geffen School of Medicine at the University of California Los Angeles, Box 951763, Los Angeles, CA 90095-1763, USA
| | - A.Y. Fong
- Department of Physiology, University of Melbourne, Melbourne 3010, VIC Australia
| | - S. Hülsmann
- Clinic for Anesthesiology, RG experimental Neuroanesthesiology, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - K.M. Morris
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - J.M. Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA,Department of Neurological Surgery, University of Washington, Seattle, WA 98104, USA
| | - J.C. Smith
- Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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15
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Oke Y, Miwakeichi F, Oku Y, Hirrlinger J, Hülsmann S. Corrigendum: Cell Type-Dependent Activation Sequence During Rhythmic Bursting in the PreBötzinger Complex in Respiratory Rhythmic Slices From Mice. Front Physiol 2018; 9:1586. [PMID: 30459644 PMCID: PMC6238538 DOI: 10.3389/fphys.2018.01586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 11/27/2022] Open
Affiliation(s)
- Yoshihiko Oke
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Fumikazu Miwakeichi
- Department of Statistical Modeling, The Institute of Statistical Mathematics, Tachikawa, Japan.,Department of Statistical Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies (SOKENDAI), Tachikawa, Japan
| | - Yoshitaka Oku
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center Göttingen, Göttingen, Germany.,Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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16
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Hülsmann S, Oke Y, Mesuret G, Latal AT, Fortuna MG, Niebert M, Hirrlinger J, Fischer J, Hammerschmidt K. The postnatal development of ultrasonic vocalization-associated breathing is altered in glycine transporter 2-deficient mice. J Physiol 2018; 597:173-191. [PMID: 30296333 DOI: 10.1113/jp276976] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 08/15/2018] [Accepted: 10/01/2018] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS Newborn mice produce ultrasonic vocalization to communicate with their mother. The neuronal glycine transporter (GlyT2) is required for efficient loading of synaptic vesicles in glycinergic neurons. Mice lacking GlyT2 develop a phenotype that resembles human hyperekplexia and the mice die in the second postnatal week. In the present study, we show that GlyT2-knockout mice do not acquire adult ultrasonic vocalization-associated breathing patterns. Despite the strong impairment of glycinergic inhibition, they can produce sufficient expiratory airflow to produce ultrasonic vocalization. Because mouse ultrasonic vocalization is a valuable read-out in translational research, these data are highly relevant for a broad range of research fields. ABSTRACT Mouse models are instrumental with respect to determining the genetic basis and neural foundations of breathing regulation. To test the hypothesis that glycinergic synaptic inhibition is required for normal breathing and proper post-inspiratory activity, we analysed breathing and ultrasonic vocalization (USV) patterns in neonatal mice lacking the neuronal glycine transporter (GlyT2). GlyT2-knockout (KO) mice have a profound reduction of glycinergic synaptic currents already at birth, develop a severe motor phenotype and survive only until the second postnatal week. At this stage, GlyT2-KO mice are smaller, have a reduced respiratory rate and still display a neonatal breathing pattern with active expiration for the production of USV. By contrast, wild-type mice acquire different USV-associated breathing patterns that depend on post-inspiratory control of air flow. Nonetheless, USVs per se remain largely indistinguishable between both genotypes. We conclude that GlyT2-KO mice, despite the strong impairment of glycinergic inhibition, can produce sufficient expiratory airflow to produce ultrasonic vocalization.
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Affiliation(s)
- Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Yoshihiko Oke
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Guillaume Mesuret
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - A Tobias Latal
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Michal G Fortuna
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Marcus Niebert
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany.,Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen, Germany
| | - Julia Fischer
- German Primate Center - Leibniz Institute for Primate Research, Cognitive Ethology Laboratory, Göttingen, Germany
| | - Kurt Hammerschmidt
- German Primate Center - Leibniz Institute for Primate Research, Cognitive Ethology Laboratory, Göttingen, Germany
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17
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Oke Y, Miwakeichi F, Oku Y, Hirrlinger J, Hülsmann S. Cell Type-Dependent Activation Sequence During Rhythmic Bursting in the PreBötzinger Complex in Respiratory Rhythmic Slices From Mice. Front Physiol 2018; 9:1219. [PMID: 30233397 PMCID: PMC6129845 DOI: 10.3389/fphys.2018.01219] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [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: 05/16/2018] [Accepted: 08/13/2018] [Indexed: 11/13/2022] Open
Abstract
Spontaneous respiratory rhythmic burst activity can be preserved in the preBötzinger Complex (preBötC) of rodent medullary transverse slices. It is known, that the activation sequence of inspiratory neurons in the preBötC stochastically varies from cycle to cycle. To test whether the activation timing of an inspiratory neuron depends on its neurotransmitter, we performed calcium imaging of preBötC neurons using double-transgenic mice expressing EGFP in GlyT2+ neurons and tdTomato in GAD65+ neurons. Five types of inspiratory neurons were identified using the fluorescence protein expression and the maximum cross-correlation coefficient between neuronal calcium fluctuation and field potential. Regarding the activation sequence, irregular type putative excitatory (GlyT2-/GAD65-) neurons and irregular type glycinergic (GlyT2+/GAD65-) neurons tended to be activated early, while regular type putative excitatory neurons, regular type glycinergic neurons tended to be activated later. In conclusion, the different cell types define a general framework for the stochastically changing activation sequence of inspiratory neurons in the preBötC.
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Affiliation(s)
- Yoshihiko Oke
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Fumikazu Miwakeichi
- Department of Statistical Modeling, The Institute of Statistical Mathematics, Tachikawa, Japan.,Department of Statistical Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies, Hayama, Japan
| | - Yoshitaka Oku
- Division of Physiome, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center Göttingen, Göttingen, Germany.,Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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18
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Mesuret G, Khabbazzadeh S, Bischoff AM, Safory H, Wolosker H, Hülsmann S. A neuronal role of the Alanine-Serine-Cysteine-1 transporter (SLC7A10, Asc-1) for glycine inhibitory transmission and respiratory pattern. Sci Rep 2018; 8:8536. [PMID: 29867218 PMCID: PMC5986860 DOI: 10.1038/s41598-018-26868-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/16/2018] [Indexed: 12/31/2022] Open
Abstract
The Alanine-Serine-Cysteine-1 transporter (SLC7A10, Asc-1) has been shown to play a role in synaptic availability of glycine although the exact mechanism remains unclear. We used electrophysiological recordings and biochemical experiments to investigate the role of Asc-1 transporter in glycinergic transmission in the brainstem respiratory network. Using both the Asc-1 substrate and transportable inhibitor D-isoleucine (D-Ile), and the non-transportable Asc-1 blocker Lu AE00527 (Lu), we found that D-Ile reduces glycinergic transmission and increases glycine release via hetero-exchange, whereas Lu has no acute effect on glycinergic synaptic transmission. Furthermore, D-Ile increases the frequency and reduces amplitude of the phrenic nerve activity in the arterially-perfused working heart brainstem preparation. These results suggest a role of Asc-1 in modulating presynaptic glycine levels that can impact on the respiratory network.
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Affiliation(s)
- Guillaume Mesuret
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | | | - Anne M Bischoff
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany
| | - Hazem Safory
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 31096, Israel
| | - Herman Wolosker
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 31096, Israel
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany. .,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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19
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Vogelgesang S, Niebert M, Bischoff AM, Hülsmann S, Manzke T. Persistent Expression of Serotonin Receptor 5b Alters Breathing Behavior in Male MeCP2 Knockout Mice. Front Mol Neurosci 2018. [PMID: 29515365 PMCID: PMC5826236 DOI: 10.3389/fnmol.2018.00028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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] [Indexed: 11/16/2022] Open
Abstract
Mutations in the transcription factor methyl-CpG-binding protein 2 (MeCP2) cause the neurodevelopmental disorder Rett syndrome (RTT). Besides many other neurological problems, RTT patients show irregular breathing with recurrent apneas or breath-holdings. MeCP2-deficient mice, which recapitulate this breathing phenotype, show a dysregulated, persistent expression of G-protein-coupled serotonin receptor 5-ht5b (Htr5b) in the brainstem. To investigate whether the persistence of 5-ht5b expression is contributing to the respiratory phenotype, we crossbred MeCP2-deficient mice with 5-ht5b-deficient mice to generate double knockout mice (Mecp2−/y;Htr5b−/−). To compare respiration between wild type (WT), Mecp2−/y and Mecp2−/y;Htr5b−/− mice, we used unrestrained whole-body plethysmography. While the breathing of MeCP2-deficient male mice (Mecp2−/y) at postnatal day 40 is characterized by a slow breathing rate and the occurrence of prolonged respiratory pauses, we found that in MeCP2-deficient mice, which also lacked the 5-ht5b receptor, the breathing rate and the number of pauses were indistinguishable from WT mice. To test for a potential mechanism, we also analyzed if the known coupling of 5-ht5b receptors to Gi proteins is altering second messenger signaling. Tissue cAMP levels in the medulla of Mecp2−/y mice were decreased as compared to WT mice. In contrast, cAMP levels in Mecp2−/y;Htr5b−/− mice were indistinguishable from WT mice. Taken together, our data points towards a role of 5-ht5b receptors within the complex breathing phenotype of MeCP2-deficient mice.
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Affiliation(s)
- Steffen Vogelgesang
- DFG-Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany.,Institute of Neuro- and Sensory Physiology, University of Göttingen, Göttingen, Germany
| | - Marcus Niebert
- DFG-Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany.,Institute of Neuro- and Sensory Physiology, University of Göttingen, Göttingen, Germany
| | - Anne M Bischoff
- DFG-Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany.,Clinic for Anesthesiology, University Medical Göttingen, Göttingen, Germany
| | - Swen Hülsmann
- DFG-Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany.,Clinic for Anesthesiology, University Medical Göttingen, Göttingen, Germany
| | - Till Manzke
- DFG-Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany.,Institute of Neuro- and Sensory Physiology, University of Göttingen, Göttingen, Germany
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20
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Mesuret G, Dannenberg J, Arnoldt M, Grützner AA, Niebert M, Hülsmann S. Breathing disturbances in a model of Rett syndrome: A potential involvement of the glycine receptor α3 subunit? Respir Physiol Neurobiol 2018; 248:43-47. [DOI: 10.1016/j.resp.2017.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 11/30/2022]
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21
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Han K, Müller UC, Hülsmann S. Amyloid-precursor Like Proteins APLP1 and APLP2 Are Dispensable for Normal Development of the Neonatal Respiratory Network. Front Mol Neurosci 2017; 10:189. [PMID: 28690498 PMCID: PMC5479907 DOI: 10.3389/fnmol.2017.00189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 02/28/2017] [Accepted: 05/29/2017] [Indexed: 11/13/2022] Open
Abstract
Recent studies using animal models indicated that the members of the amyloid precursor protein (APP) gene family are important for the formation, maintenance, and plasticity of synapses. Despite this, the specific role of the APP homologs APLP1 and APLP2 within the CNS and PNS is still poorly understood. In contrast to the subtle phenotypes of single mutants, double knockout mice (DKO) lacking APP/APLP2 or APLP1/APLP2 die within the first day after birth. Whereas APP/APLP2-DKO mice show severe deficits of neuromuscular morphology and transmission, the underlying cause of lethality of APLP1/APLP2-DKO mice remains unclear. Since expression of both proteins was confirmed by in situ hybridization, we aimed to test the role of APLP1/APLP2 in the formation and maintenance of synapses in the brainstem, and assessed a potential dysfunction of the most vital central neuronal network in APLP1/APLP2-DKO mice by analyzing the respiratory network of the medulla. We performed in vivo unrestrained whole body plethysmography in newborn APLP1/APLP2-DKO mice at postnatal day zero. Additionally, we directly tested the activity of the respiratory network in an acute slice preparation that includes the pre-Bötzinger complex. In both sets of experiments, no significant differences were detected regarding respiratory rate and cycle variability, strongly arguing against central respiratory problems as the primary cause of death of APLP1/APLP2-DKO mice. Thus, we conclude that APLP1 and APLP2 are dispensable for the development of the network and the generation of a normal breathing rhythm.
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Affiliation(s)
- Kang Han
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg UniversityHeidelberg, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg UniversityHeidelberg, Germany
| | - Swen Hülsmann
- Klinik für Anästhesiologie, Universitätsmedizin GöttingenGöttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
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22
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Vogelgesang S, Niebert S, Renner U, Möbius W, Hülsmann S, Manzke T, Niebert M. Analysis of the Serotonergic System in a Mouse Model of Rett Syndrome Reveals Unusual Upregulation of Serotonin Receptor 5b. Front Mol Neurosci 2017; 10:61. [PMID: 28337123 PMCID: PMC5340760 DOI: 10.3389/fnmol.2017.00061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [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: 10/31/2016] [Accepted: 02/23/2017] [Indexed: 12/03/2022] Open
Abstract
Mutations in the transcription factor methyl-CpG-binding-protein 2 (MeCP2) cause a delayed-onset neurodevelopmental disorder known as Rett syndrome (RTT). Although alteration in serotonin levels have been reported in RTT patients, the molecular mechanisms underlying these defects are not well understood. Therefore, we chose to investigate the serotonergic system in hippocampus and brainstem of male Mecp2-/y knock-out mice in the B6.129P2(C)-Mecp2(tm1.1Bird) mouse model of RTT. The serotonergic system in mouse is comprised of 16 genes, whose mRNA expression profile was analyzed by quantitative RT-PCR. Mecp2-/y mice are an established animal model for RTT displaying most of the cognitive and physical impairments of human patients and the selected areas receive significant modulation through serotonin. Using anatomically and functional characterized areas, we found region-specific differential expression between wild type and Mecp2-/y mice at post-natal day 40. In brainstem, we found five genes to be dysregulated, while in hippocampus, two genes were dysregulated. The one gene dysregulated in both brain regions was dopamine decarboxylase, but of special interest is the serotonin receptor 5b (5-ht5b), which showed 75-fold dysregulation in brainstem of Mecp2-/y mice. This dysregulation was not due to upregulation, but due to failure of down-regulation in Mecp2-/y mice during development. Detailed analysis of 5-ht5b revealed a receptor that localizes to endosomes and interacts with Gαi proteins.
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Affiliation(s)
- Steffen Vogelgesang
- DFG Research Center and Excellence Cluster Microscopy at the Nanometer Range and Molecular Physiology of the Brain Göttingen, Germany
| | - Sabine Niebert
- Department of Maxillofacial Surgery, University Medical Center Göttingen, Germany
| | - Ute Renner
- DFG Research Center and Excellence Cluster Microscopy at the Nanometer Range and Molecular Physiology of the Brain Göttingen, Germany
| | - Wiebke Möbius
- DFG Research Center and Excellence Cluster Microscopy at the Nanometer Range and Molecular Physiology of the BrainGöttingen, Germany; Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingen, Germany
| | - Swen Hülsmann
- DFG Research Center and Excellence Cluster Microscopy at the Nanometer Range and Molecular Physiology of the BrainGöttingen, Germany; Clinic for Anesthesiology, University Medical CenterGöttingen, Germany
| | - Till Manzke
- DFG Research Center and Excellence Cluster Microscopy at the Nanometer Range and Molecular Physiology of the Brain Göttingen, Germany
| | - Marcus Niebert
- DFG Research Center and Excellence Cluster Microscopy at the Nanometer Range and Molecular Physiology of the BrainGöttingen, Germany; Institute of Neuro- and Sensory Physiology, University Medical CenterGöttingen, Germany
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23
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Abstract
Since 2004, the red fluorescent dye Sulforhodamine 101 (SR101) has been boosting the functional analysis of astrocytes in a functional environment in an unprecedented way. However, two major limitations have been challenging the usefulness of this tool for cellular imaging: (i) SR101 is not as specific for astrocytes as previously reported; and (ii) discoveries of severe excitatory side effects of SR101 are bearing the risk of unwanted alteration of the system of interest. In this article, we summarize the current knowledge about SR101-labeling protocols and discuss the problems that arise from varying of the staining protocols. Furthermore, we provide a testable hypothesis for the observed hyper-excitability that can be observed when using SR101.
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Affiliation(s)
- Swen Hülsmann
- Clinic for Anesthesiology, University Hospital GöttingenGöttingen, Germany; DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
| | - Liya Hagos
- Clinic for Anesthesiology, University Hospital GöttingenGöttingen, Germany; DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
| | - Heike Heuer
- Leibniz-Institut für Umweltmedizinische Forschung GmbH Düsseldorf, Germany
| | - Christian Schnell
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) Göttingen, Germany
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24
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Oku Y, Hülsmann S. A computational model of the respiratory network challenged and optimized by data from optogenetic manipulation of glycinergic neurons. Neuroscience 2017; 347:111-122. [PMID: 28215988 DOI: 10.1016/j.neuroscience.2017.01.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 11/13/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/14/2022]
Abstract
The topology of the respiratory network in the brainstem has been addressed using different computational models, which help to understand the functional properties of the system. We tested a neural mass model by comparing the result of activation and inhibition of inhibitory neurons in silico with recently published results of optogenetic manipulation of glycinergic neurons [Sherman, et al. (2015) Nat Neurosci 18:408]. The comparison revealed that a five-cell type model consisting of three classes of inhibitory neurons [I-DEC, E-AUG, E-DEC (PI)] and two excitatory populations (pre-I/I) and (I-AUG) neurons can be applied to explain experimental observations made by stimulating or inhibiting inhibitory neurons by light sensitive ion channels.
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Affiliation(s)
- Yoshitaka Oku
- Department of Physiology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Hospital Göttingen, Göttingen 37099, Germany; DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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25
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Abstract
Background: Studying astrocytes in higher brain functions has been hampered by the lack of genetic tools for the efficient expression of inducible Cre recombinase throughout the CNS, including the neocortex.
Methods: Therefore, we generated BAC transgenic mice, in which CreERT2 is expressed under control of the
Aldh1l1 regulatory region.
Results: When crossbred to Cre reporter mice, adult Aldh1l1-CreERT2 mice show efficient gene targeting in astrocytes. No such Cre-mediated recombination was detectable in CNS neurons, oligodendrocytes, and microglia. As expected, Aldh1l1-CreERT2 expression was evident in several peripheral organs, including liver and kidney.
Conclusions: Taken together, Aldh1l1-CreERT2 mice are a useful tool for studying astrocytes in neurovascular coupling, brain metabolism, synaptic plasticity and other aspects of neuron-glia interactions.
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Affiliation(s)
- Jan Winchenbach
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Tim Düking
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Stefan A Berghoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sina K Stumpf
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, Research Group Central Respiratory Control, University Medical Center Göttingen, Experimental Neuroanesthesiology, Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Janc OA, Hüser MA, Dietrich K, Kempkes B, Menzfeld C, Hülsmann S, Müller M. Systemic Radical Scavenger Treatment of a Mouse Model of Rett Syndrome: Merits and Limitations of the Vitamin E Derivative Trolox. Front Cell Neurosci 2016; 10:266. [PMID: 27895554 PMCID: PMC5109403 DOI: 10.3389/fncel.2016.00266] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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: 08/18/2016] [Accepted: 11/01/2016] [Indexed: 12/21/2022] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder typically arising from spontaneous mutations in the X-chromosomal methyl-CpG binding protein 2 (MECP2) gene. The almost exclusively female Rett patients show an apparently normal development during their first 6-18 months of life. Subsequently, cognitive- and motor-impairment, hand stereotypies, loss of learned skills, epilepsy and irregular breathing manifest. Early mitochondrial impairment and oxidative challenge are considered to facilitate disease progression. Along this line, we recently confirmed in vitro that acute treatment with the vitamin E-derivative Trolox dampens neuronal hyperexcitability, reinstates synaptic plasticity, ameliorates cellular redox balance and improves hypoxia tolerance in male MeCP2-deficient (Mecp2-/y ) mouse hippocampus. Pursuing these promising findings, we performed a preclinical study to define the merit of systemic Trolox administration. Blinded, placebo-controlled in vivo treatment of male mice started at postnatal day (PD) 10-11 and continued for ~40 days. Compounds (vehicle only, 10 mg/kg or 40 mg/kg Trolox) were injected intraperitoneally every 48 h. Detailed phenotyping revealed that in Mecp2-/y mice, blood glucose levels, lipid peroxidation, synaptic short-term plasticity, hypoxia tolerance and certain forms of environmental exploration were improved by Trolox. Yet, body weight and size, motor function and the rate and regularity of breathing did not improve. In conclusion, in vivo Trolox treatment partially ameliorated a subset of symptoms of the complex Rett phenotype, thereby confirming a partial merit of the vitamin E-derivative based pharmacotherapy. Yet, it also became evident that frequent animal handling and the route of drug administration are critical issues to be optimized in future trials.
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Affiliation(s)
- Oliwia A Janc
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Marc A Hüser
- Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Germany
| | - Katharina Dietrich
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Belinda Kempkes
- Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-Universität Göttingen, Germany
| | - Christiane Menzfeld
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Swen Hülsmann
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Klinik für Anästhesiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
| | - Michael Müller
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro- und Sinnesphysiologie, Universitätsmedizin Göttingen, Georg-August-UniversitätGöttingen, Germany
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Dullin C, Markus MA, Larsson E, Tromba G, Hülsmann S, Alves F. X-Ray based Lung Function measurement-a sensitive technique to quantify lung function in allergic airway inflammation mouse models. Sci Rep 2016; 6:36297. [PMID: 27805632 PMCID: PMC5090985 DOI: 10.1038/srep36297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/13/2016] [Indexed: 11/30/2022] Open
Abstract
In mice, along with the assessment of eosinophils, lung function measurements, most commonly carried out by plethysmography, are essential to monitor the course of allergic airway inflammation, to examine therapy efficacy and to correlate animal with patient data. To date, plethysmography techniques either use intubation and/or restraining of the mice and are thus invasive, or are limited in their sensitivity. We present a novel unrestrained lung function method based on low-dose planar cinematic x-ray imaging (X-Ray Lung Function, XLF) and demonstrate its performance in monitoring OVA induced experimental allergic airway inflammation in mice and an improved assessment of the efficacy of the common treatment dexamethasone. We further show that XLF is more sensitive than unrestrained whole body plethysmography (UWBP) and that conventional broncho-alveolar lavage and histology provide only limited information of the efficacy of a treatment when compared to XLF. Our results highlight the fact that a multi-parametric imaging approach as delivered by XLF is needed to address the combined cellular, anatomical and functional effects that occur during the course of asthma and in response to therapy.
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Affiliation(s)
- C Dullin
- Institute for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Germany.,Italian Synchrotron Light Source 'Elettra' Trieste, Italy
| | - M A Markus
- Max-Plank-Institute for Experimental Medicine, Dept. of Molecular Biology of Neuronal Signals, Goettingen, Germany
| | - E Larsson
- Italian Synchrotron Light Source 'Elettra' Trieste, Italy
| | - G Tromba
- Italian Synchrotron Light Source 'Elettra' Trieste, Italy
| | - S Hülsmann
- Clinic for Anesthesiology, University Medical Center, Goettingen, Germany
| | - F Alves
- Institute for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Germany.,Max-Plank-Institute for Experimental Medicine, Dept. of Molecular Biology of Neuronal Signals, Goettingen, Germany.,Department of Hematology and Medical Oncology, University Medical Center, Goettingen, Germany
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Hülsmann S, Mesuret G, Dannenberg J, Arnoldt M, Niebert M. GlyT2-Dependent Preservation of MECP2-Expression in Inhibitory Neurons Improves Early Respiratory Symptoms but Does Not Rescue Survival in a Mouse Model of Rett Syndrome. Front Physiol 2016; 7:385. [PMID: 27672368 PMCID: PMC5018520 DOI: 10.3389/fphys.2016.00385] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [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: 06/15/2016] [Accepted: 08/22/2016] [Indexed: 11/25/2022] Open
Abstract
Mutations in methyl-CpG-binding protein 2 (MECP2) gene have been shown to manifest in a neurodevelopmental disorder that is called Rett syndrome. A typical problem that occurs during development is a disturbance of breathing. To address the role of inhibitory neurons, we generated a mouse line that restores MECP2 in inhibitory neurons in the brainstem by crossbreeding a mouse line that expresses the Cre-recombinase (Cre) in inhibitory neurons under the control of the glycine transporter 2 (GlyT2, slc6a5) promotor (GlyT2-Cre) with a mouse line that has a floxed-stop mutation of the Mecp2 gene (Mecp2stop/y). Unrestrained whole-body-plethysmography at postnatal day P60 revealed a low respiratory rate and prolonged respiratory pauses in Mecp2stop/y mice. In contrast, GlyT2-Cre positive Mecp2stop/y mice (Cre+; Mecp2stop/y) showed greatly improved respiration and were indistinguishable from wild type littermates. These data support the concept that alterations in inhibitory neurons are important for the development of the respiratory phenotype in Rett syndrome.
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Affiliation(s)
- Swen Hülsmann
- Clinic for Anesthesiology, University Medical CenterGöttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the BrainGöttingen, Germany
| | - Guillaume Mesuret
- Clinic for Anesthesiology, University Medical CenterGöttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the BrainGöttingen, Germany
| | - Julia Dannenberg
- Clinic for Anesthesiology, University Medical Center Göttingen, Germany
| | - Mauricio Arnoldt
- Clinic for Anesthesiology, University Medical Center Göttingen, Germany
| | - Marcus Niebert
- Center for Nanoscale Microscopy and Molecular Physiology of the BrainGöttingen, Germany; Institute of Neuro- and Sensory Physiology, University Medical Center GöttingenGöttingen, Germany
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Hagos L, Hülsmann S. Unspecific labelling of oligodendrocytes by sulforhodamine 101 depends on astrocytic uptake via the thyroid hormone transporter OATP1C1 (SLCO1C1). Neurosci Lett 2016; 631:13-18. [PMID: 27519929 DOI: 10.1016/j.neulet.2016.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [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: 06/15/2016] [Revised: 08/08/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
The red fluorescent dye Sulforhodamine 101 (SR101) is often used as a marker for astrocytes, although variations of the staining protocol have been shown to influence the preferentially labeled cell type. Here we analyzed SR101-labeling of oligodendrocytes in the hippocampal slices preparation of PLP-EGFP mice. Using different staining protocols, we found robust SR101-labeled oligodendrocytes in the CA1 stratum radiatum of the hippocampus. Application of L-thyroxin, which is known to block SR101 transport into astrocytes via competitive inhibition of the multi-specific OATP1C1 (SLCO1C1) transporter, significantly reduced oligodendrocyte labeling. Since OATP1C1 is not expressed in oligodendrocytes, we conclude that oligodendrocyte labeling with SR101 requires SR101-uptake by astrocytes, which then diffuses to oligodendrocytes via heterotypic gap junctions of the pan-glial network. In summary, unequivocal identification of a particular cell type is not possible by SR101 only, hence caution is recommended when using SR101 in future studies.
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Affiliation(s)
- Liya Hagos
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Germany
| | - Swen Hülsmann
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Germany.
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30
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Kono Y, Hülsmann S. Presynaptic facilitation of glycinergic mIPSC is reduced in mice lacking α3 glycine receptor subunits. Neuroscience 2016; 320:1-7. [PMID: 26851771 DOI: 10.1016/j.neuroscience.2016.01.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 11/13/2015] [Revised: 01/12/2016] [Accepted: 01/28/2016] [Indexed: 01/03/2023]
Abstract
Glycinergic neurons provide an important mechanism to control excitation of motoneurons in the brainstem and a reduction or loss of glycinergic inhibition can be deleterious by leading to hyperexcitation such as in hyperekplexia or neurodegeneration and neuronal death as in amyotrophic lateral sclerosis (ALS). Second messenger systems that change cyclic AMP and lead to phosphorylation of the α3 subunit of the glycine receptor (GlyR α3) have been shown to be potent modulators of synaptic inhibition in the spinal cord and brain stem. In this study we analyzed the role of GlyR α3 in synaptic inhibition to the hypoglossal nucleus using Glra3 (the gene encoding the glycine receptor α3 subunit) knockout mice. We observed that baseline glycinergic synaptic transmission to nucleus of hypoglossal motoneurons is rather normal in Glra3 knockout mice. Interestingly, we found that the modulation of synaptic transmission by cAMP-mediated pathways appeared to be reduced in Glra3 knockout mice. In the second postnatal week the forskolin-induced increase of miniature inhibitory postsynaptic potential (mIPSC) frequency was significantly larger in control as compared to Glra3 knockout mice suggesting that presynaptic glycine release in the hypoglossal nucleus is partially depending on GlyR α3.
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Affiliation(s)
- Y Kono
- Department of Neurology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan.
| | - S Hülsmann
- Clinic for Anesthesiology, University Medical Center, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
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31
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Besser S, Sicker M, Marx G, Winkler U, Eulenburg V, Hülsmann S, Hirrlinger J. A Transgenic Mouse Line Expressing the Red Fluorescent Protein tdTomato in GABAergic Neurons. PLoS One 2015; 10:e0129934. [PMID: 26076353 PMCID: PMC4468179 DOI: 10.1371/journal.pone.0129934] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/13/2015] [Indexed: 12/25/2022] Open
Abstract
GABAergic inhibitory neurons are a large population of neurons in the central nervous system (CNS) of mammals and crucially contribute to the function of the circuitry of the brain. To identify specific cell types and investigate their functions labelling of cell populations by transgenic expression of fluorescent proteins is a powerful approach. While a number of mouse lines expressing the green fluorescent protein (GFP) in different subpopulations of GABAergic cells are available, GFP expressing mouse lines are not suitable for either crossbreeding to other mouse lines expressing GFP in other cell types or for Ca2+-imaging using the superior green Ca2+-indicator dyes. Therefore, we have generated a novel transgenic mouse line expressing the red fluorescent protein tdTomato in GABAergic neurons using a bacterial artificial chromosome based strategy and inserting the tdTomato open reading frame at the start codon within exon 1 of the GAD2 gene encoding glutamic acid decarboxylase 65 (GAD65). TdTomato expression was observed in all expected brain regions; however, the fluorescence intensity was highest in the olfactory bulb and the striatum. Robust expression was also observed in cortical and hippocampal neurons, Purkinje cells in the cerebellum, amacrine cells in the retina as well as in cells migrating along the rostral migratory stream. In cortex, hippocampus, olfactory bulb and brainstem, 80% to 90% of neurons expressing endogenous GAD65 also expressed the fluorescent protein. Moreover, almost all tdTomato-expressing cells coexpressed GAD65, indicating that indeed only GABAergic neurons are labelled by tdTomato expression. This mouse line with its unique spectral properties for labelling GABAergic neurons will therefore be a valuable new tool for research addressing this fascinating cell type.
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Affiliation(s)
- Stefanie Besser
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Marit Sicker
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Grit Marx
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Ulrike Winkler
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Volker Eulenburg
- Institute for Biochemistry and Molecular Medicine, University of Erlangen, Erlangen, Germany
| | - Swen Hülsmann
- Laboratory for Experimental Neuroanesthesiology, Clinic for Anesthesiology, University Hospital Göttingen, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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32
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Safory H, Neame S, Shulman Y, Zubedat S, Radzishevsky I, Rosenberg D, Sason H, Engelender S, Avital A, Hülsmann S, Schiller J, Wolosker H. The alanine-serine-cysteine-1 (Asc-1) transporter controls glycine levels in the brain and is required for glycinergic inhibitory transmission. EMBO Rep 2015; 16:590-8. [PMID: 25755256 DOI: 10.15252/embr.201439561] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [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: 09/10/2014] [Accepted: 02/13/2015] [Indexed: 11/09/2022] Open
Abstract
Asc-1 (SLC7A10) is an amino acid transporter whose deletion causes neurological abnormalities and early postnatal death in mice. Using metabolomics and behavioral and electrophysiological methods, we demonstrate that Asc-1 knockout mice display a marked decrease in glycine levels in the brain and spinal cord along with impairment of glycinergic inhibitory transmission, and a hyperekplexia-like phenotype that is rescued by replenishing brain glycine. Asc-1 works as a glycine and L-serine transporter, and its transport activity is required for the subsequent conversion of L-serine into glycine in vivo. Asc-1 is a novel regulator of glycine metabolism and a candidate for hyperekplexia disorders.
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Affiliation(s)
- Hazem Safory
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Samah Neame
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yoav Shulman
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Salman Zubedat
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Inna Radzishevsky
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Dina Rosenberg
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Hagit Sason
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Simone Engelender
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Avi Avital
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel Emek Medical Center, Afula, Israel
| | - Swen Hülsmann
- Department of Anesthesiology, Emergency and Intensive Care Medicine and Center for Nanoscale Microscopy and Molecular Physiology of the Brain Georg-August-University, Göttingen, Germany
| | - Jackie Schiller
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Herman Wolosker
- The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
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Oku Y, Fresemann J, Miwakeichi F, Hülsmann S. Respiratory calcium fluctuations in low-frequency oscillating astrocytes in the pre-Bötzinger complex. Respir Physiol Neurobiol 2015; 226:11-7. [PMID: 25747384 DOI: 10.1016/j.resp.2015.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [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: 12/20/2014] [Revised: 02/20/2015] [Accepted: 02/22/2015] [Indexed: 11/18/2022]
Abstract
Astrocytes have been found to modulate neuronal activity through calcium-dependent signaling in various brain regions. However, whether astrocytes of the pre-Bötzinger complex (preBötC) exhibit respiratory rhythmic fluctuations is still controversial. Here we evaluated calcium-imaging experiments within preBötC in rhythmically active medullary slices from TgN(hGFAP-EGFP) mice using advanced analyses. 13.8% of EGFP-negative cells, putative neurons, showed rhythmic fluorescent changes that were highly correlated to the respiratory rhythmic fluctuation (cross-correlation coefficient>0.5 and dF/F>0.2%). In contrast, a considerable number of astrocyte somata exhibited synchronized low-frequency (<0.03Hz) calcium oscillations. After band-pass filtering, signals that irregularly preceded the calcium signal of EGFP-negative cells were observed in 10.2% of astrocytes, indicating a functional coupling between astrocytes and neurons in preBötC. A model simulation confirmed that such preinspiratory astrocytic signals can arise from coupled neuronal and astrocytic oscillators, supporting a concept that slow oscillatory changes of astrocytic functions modulate neighboring neuronal activity to add variability in respiratory rhythm.
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Affiliation(s)
- Yoshitaka Oku
- Department of Physiology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
| | - Jens Fresemann
- Clinic for Anesthesiology, Laboratory for Experimental Neuroanesthesiology, University Hospital Göttingen, 37099 Göttingen, Germany
| | - Fumikazu Miwakeichi
- Department of Statistical Modeling, The Institute of Statistical Mathematics, Tokyo 190-8562, Japan; Department of Statistical Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies, Tokyo 190-8562, Japan
| | - Swen Hülsmann
- Clinic for Anesthesiology, Laboratory for Experimental Neuroanesthesiology, University Hospital Göttingen, 37099 Göttingen, Germany; DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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Wegener E, Brendel C, Fischer A, Hülsmann S, Gärtner J, Huppke P. Characterization of the MeCP2R168X knockin mouse model for Rett syndrome. PLoS One 2014; 9:e115444. [PMID: 25541993 PMCID: PMC4277341 DOI: 10.1371/journal.pone.0115444] [Citation(s) in RCA: 30] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/24/2014] [Indexed: 11/19/2022] Open
Abstract
Rett syndrome, one of the most common causes of mental retardation in females, is caused by mutations in the X chromosomal gene MECP2. Mice deficient for MeCP2 recapitulate some of the symptoms seen in patients with Rett syndrome. It has been shown that reactivation of silent MECP2 alleles can reverse some of the symptoms in these mice. We have generated a knockin mouse model for translational research that carries the most common nonsense mutation in Rett syndrome, R168X. In this article we describe the phenotype of this mouse model. In male MeCP2(R168X) mice life span was reduced to 12-14 weeks and bodyweight was significantly lower than in wild type littermates. First symptoms including tremor, hind limb clasping and inactivity occurred at age 27 days. At age 6 weeks nest building, rotarod, open-field and elevated plus maze experiments showed impaired motor performance, reduced activity and decreased anxiety-like behavior. Plethysmography at the same time showed apneas and irregular breathing with reduced frequency. Female MeCP2R168X mice showed no significant abnormalities except decreased performance on the rotarod at age 9 months. In conclusion we show that the male MeCP2(R168X) mice have a phenotype similar to that seen in MECP2 knockout mouse models and are therefore well suited for translational research. The female mice, however, have a much milder and less constant phenotype making such research with this mouse model more challenging.
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Affiliation(s)
- Eike Wegener
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
| | - Cornelia Brendel
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
| | - Andre Fischer
- German Center for Neurodegenerative Diseases, Göttingen, Germany
- University Medical Center Göttingen, Department for Psychiatry and Psychotherapy, Göttingen, Germany
| | - Swen Hülsmann
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Jutta Gärtner
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
| | - Peter Huppke
- University Medical Center Göttingen, Department of Child and Adolescent Health – Division of Neuropediatrics, Göttingen, Germany
- * E-mail:
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Rahman J, Latal AT, Besser S, Hirrlinger J, Hülsmann S. Mixed miniature postsynaptic currents resulting from co-release of glycine and GABA recorded from glycinergic neurons in the neonatal respiratory network. Eur J Neurosci 2013; 37:1229-41. [DOI: 10.1111/ejn.12136] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 12/28/2022]
Affiliation(s)
| | - A. Tobias Latal
- DFG Research Center for Molecular Physiology of the Brain (CMPB); University of Göttingen; Göttingen; Germany
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Zschüntzsch J, Schütze S, Hülsmann S, Dibaj P, Neusch C. Heterologous expression of a glial Kir channel (KCNJ10) in a neuroblastoma spinal cord (NSC-34) cell line. Physiol Res 2012; 62:95-105. [PMID: 23173681 DOI: 10.33549/physiolres.932264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterologous expression of Kir channels offers a tool to modulate excitability of neurons which provide insight into Kir channel functions in general. Inwardly-rectifying K+ channels (Kir channels) are potential candidate proteins to hyperpolarize neuronal cell membranes. However, heterologous expression of inwardly-rectifying K+ channels has previously proven to be difficult. This was mainly due to a high toxicity of the respective Kir channel expression. We investigated the putative role of a predominantly glial-expressed, weakly rectifying Kir channel (Kir4.1 channel subunit; KCNJ10) in modulating electrophysiological properties of a motoneuron-like cell culture (NSC-34). Transfection procedures using an EGFP-tagged Kir4.1 protein in this study proved to have no toxic effects on NSC-34 cells. Using whole cell-voltage clamp, a substantial increase of inward rectifying K+ currents as well as hyperpolarization of the cell membrane was observed in Kir4.1-transfected cells. Na+ inward currents, observed in NSC-34 controls, were absent in Kir4.1/EGFP motoneuronal cells. The Kir4.1-transfection did not influence the NaV1.6 sodium channel expression. This study demonstrates the general feasibility of a heterologous expression of a weakly inward-rectifying K+ channel (Kir4.1 subunit) and shows that in vitro overexpression of Kir4.1 shifts electrophysiological properties of neuronal cells to a more glial-like phenotype and may therefore be a candidate tool to dampen excitability of neurons in experimental paradigms.
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Affiliation(s)
- J Zschüntzsch
- Department of Neurology, Georg-August-University, Göttingen, Germany
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Schnell C, Janc OA, Kempkes B, Callis CA, Flügge G, Hülsmann S, Müller M. Restraint Stress Intensifies Interstitial K(+) Accumulation during Severe Hypoxia. Front Pharmacol 2012; 3:53. [PMID: 22470344 PMCID: PMC3314232 DOI: 10.3389/fphar.2012.00053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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: 02/16/2012] [Accepted: 03/12/2012] [Indexed: 11/23/2022] Open
Abstract
Chronic stress affects neuronal networks by inducing dendritic retraction, modifying neuronal excitability and plasticity, and modulating glial cells. To elucidate the functional consequences of chronic stress for the hippocampal network, we submitted adult rats to daily restraint stress for 3 weeks (6 h/day). In acute hippocampal tissue slices of stressed rats, basal synaptic function and short-term plasticity at Schaffer collateral/CA1 neuron synapses were unchanged while long-term potentiation was markedly impaired. The spatiotemporal propagation pattern of hypoxia-induced spreading depression episodes was indistinguishable among control and stress slices. However, the duration of the extracellular direct current potential shift was shortened after stress. Moreover, K+ fluxes early during hypoxia were more intense, and the postsynaptic recoveries of interstitial K+ levels and synaptic function were slower. Morphometric analysis of immunohistochemically stained sections suggested hippocampal shrinkage in stressed rats, and the number of cells that are immunoreactive for glial fibrillary acidic protein was increased in the CA1 subfield indicating activation of astrocytes. Western blots showed a marked downregulation of the inwardly rectifying K+ channel Kir4.1 in stressed rats. Yet, resting membrane potentials, input resistance, and K+-induced inward currents in CA1 astrocytes were indistinguishable from controls. These data indicate an intensified interstitial K+ accumulation during hypoxia in the hippocampus of chronically stressed rats which seems to arise from a reduced interstitial volume fraction rather than impaired glial K+ buffering. One may speculate that chronic stress aggravates hypoxia-induced pathophysiological processes in the hippocampal network and that this has implications for the ischemic brain.
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Affiliation(s)
- Christian Schnell
- DFG Research Center Molecular Physiology of the Brain, Georg-August-Universität Göttingen Göttingen, Germany
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Schnell C, Fresemann J, Hülsmann S. Determinants of functional coupling between astrocytes and respiratory neurons in the pre-Bötzinger complex. PLoS One 2011; 6:e26309. [PMID: 22039458 PMCID: PMC3198395 DOI: 10.1371/journal.pone.0026309] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/23/2011] [Indexed: 12/02/2022] Open
Abstract
Respiratory neuronal network activity is thought to require efficient functioning of astrocytes. Here, we analyzed neuron-astrocyte communication in the pre-Bötzinger Complex (preBötC) of rhythmic slice preparations from neonatal mice. In astrocytes that exhibited rhythmic potassium fluxes and glutamate transporter currents, we did not find a translation of respiratory neuronal activity into phase-locked astroglial calcium signals. In up to 20% of astrocytes, 2-photon calcium imaging revealed spontaneous calcium fluctuations, although with no correlation to neuronal activity. Calcium signals could be elicited in preBötC astrocytes by metabotropic glutamate receptor activation or after inhibition of glial glutamate uptake. In the latter case, astrocyte calcium elevation preceded a surge of respiratory neuron discharge activity followed by network failure. We conclude that astrocytes do not exhibit respiratory-rhythmic calcium fluctuations when they are able to prevent synaptic glutamate accumulation. Calcium signaling is, however, observed when glutamate transport processes in astrocytes are suppressed or neuronal discharge activity is excessive.
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Affiliation(s)
- Christian Schnell
- Abt. Neuro- und Sinnesphysiologie, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, Göttingen, Germany
- DFG-Center Molecular Physiology of the Brain (CMPB), Göttingen, Germany
| | - Jens Fresemann
- Abt. Neuro- und Sinnesphysiologie, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, Göttingen, Germany
- DFG-Center Molecular Physiology of the Brain (CMPB), Göttingen, Germany
| | - Swen Hülsmann
- Abt. Neuro- und Sinnesphysiologie, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, Göttingen, Germany
- DFG-Center Molecular Physiology of the Brain (CMPB), Göttingen, Germany
- * E-mail:
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Manzke T, Niebert M, Koch UR, Caley A, Vogelgesang S, Hülsmann S, Ponimaskin E, Müller U, Smart TG, Harvey RJ, Richter DW. Serotonin receptor 1A-modulated phosphorylation of glycine receptor α3 controls breathing in mice. J Clin Invest 2010; 120:4118-28. [PMID: 20978350 DOI: 10.1172/jci43029] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 08/25/2010] [Indexed: 11/17/2022] Open
Abstract
Rhythmic breathing movements originate from a dispersed neuronal network in the medulla and pons. Here, we demonstrate that rhythmic activity of this respiratory network is affected by the phosphorylation status of the inhibitory glycine receptor α3 subtype (GlyRα3), which controls glutamatergic and glycinergic neuronal discharges, subject to serotonergic modulation. Serotonin receptor type 1A-specific (5-HTR1A-specific) modulation directly induced dephosphorylation of GlyRα3 receptors, which augmented inhibitory glycine-activated chloride currents in HEK293 cells coexpressing 5-HTR1A and GlyRα3. The 5-HTR1A-GlyRα3 signaling pathway was distinct from opioid receptor signaling and efficiently counteracted opioid-induced depression of breathing and consequential apnea in mice. Paradoxically, this rescue of breathing originated from enhanced glycinergic synaptic inhibition of glutamatergic and glycinergic neurons and caused disinhibition of their target neurons. Together, these effects changed respiratory phase alternations and ensured rhythmic breathing in vivo. GlyRα3-deficient mice had an irregular respiratory rhythm under baseline conditions, and systemic 5-HTR1A activation failed to remedy opioid-induced respiratory depression in these mice. Delineation of this 5-HTR1A-GlyRα3 signaling pathway offers a mechanistic basis for pharmacological treatment of opioid-induced apnea and other breathing disturbances caused by disorders of inhibitory synaptic transmission, such as hyperekplexia, hypoxia/ischemia, and brainstem infarction.
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Affiliation(s)
- Till Manzke
- Department of Neuro- and Sensory Physiology, University of Göttingen, Göttingen, Germany
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Lal A, Oku Y, Hülsmann S, Okada Y, Miwakeichi F, Kawai S, Tamura Y, Ishiguro M. Dual oscillator model of the respiratory neuronal network generating quantal slowing of respiratory rhythm. J Comput Neurosci 2010; 30:225-40. [PMID: 20544264 PMCID: PMC3058346 DOI: 10.1007/s10827-010-0249-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 03/10/2010] [Accepted: 05/24/2010] [Indexed: 11/28/2022]
Abstract
We developed a dual oscillator model to facilitate the understanding of dynamic interactions between the parafacial respiratory group (pFRG) and the preBötzinger complex (preBötC) neurons in the respiratory rhythm generation. Both neuronal groups were modeled as groups of 81 interconnected pacemaker neurons; the bursting cell model described by Butera and others [model 1 in Butera et al. (J Neurophysiol 81:382–397, 1999a)] were used to model the pacemaker neurons. We assumed (1) both pFRG and preBötC networks are rhythm generators, (2) preBötC receives excitatory inputs from pFRG, and pFRG receives inhibitory inputs from preBötC, and (3) persistent Na+ current conductance and synaptic current conductances are randomly distributed within each population. Our model could reproduce 1:1 coupling of bursting rhythms between pFRG and preBötC with the characteristic biphasic firing pattern of pFRG neurons, i.e., firings during pre-inspiratory and post-inspiratory phases. Compatible with experimental results, the model predicted the changes in firing pattern of pFRG neurons from biphasic expiratory to monophasic inspiratory, synchronous with preBötC neurons. Quantal slowing, a phenomena of prolonged respiratory period that jumps non-deterministically to integer multiples of the control period, was observed when the excitability of preBötC network decreased while strengths of synaptic connections between the two groups remained unchanged, suggesting that, in contrast to the earlier suggestions (Mellen et al., Neuron 37:821–826, 2003; Wittmeier et al., Proc Natl Acad Sci USA 105(46):18000–18005, 2008), quantal slowing could occur without suppressed or stochastic excitatory synaptic transmission. With a reduced excitability of preBötC network, the breakdown of synchronous bursting of preBötC neurons was predicted by simulation. We suggest that quantal slowing could result from a breakdown of synchronized bursting within the preBötC.
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Affiliation(s)
- Amit Lal
- Department of Physiology, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan
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Winter SM, Fresemann J, Schnell C, Oku Y, Hirrlinger J, Hülsmann S. Glycinergic interneurons in the respiratory network of the rhythmic slice preparation. Adv Exp Med Biol 2010; 669:97-100. [PMID: 20217329 DOI: 10.1007/978-1-4419-5692-7_20] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The neuronal network in the pre-Bötzinger Complex is the key element of respiratory rhythm generation. Isolated in a slice preparation, the pre-Bötzinger Complex network is still able to generate its inspiratory activity. Although the mechanism of rhythm generation in principle relies on glutamatergic neurons, interestingly we found that glycinergic neurons represent a major portion of all inspiratory neurons in the slice preparation.
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Affiliation(s)
- Stefan M Winter
- Abt. Neuro- und Sinnesphysiologie und DFG Forschungszentrum für Molekularphysiologie des Gehirns, Zentrum Physiologie und Pathophysiologie, Georg-August-Universität, 37073 Göttingen, Germany.
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Latal AT, Kremer T, Gomeza J, Eulenburg V, Hülsmann S. Development of synaptic inhibition in glycine transporter 2 deficient mice. Mol Cell Neurosci 2010; 44:342-52. [PMID: 20447457 DOI: 10.1016/j.mcn.2010.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [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: 03/09/2010] [Revised: 04/19/2010] [Accepted: 04/23/2010] [Indexed: 11/20/2022] Open
Abstract
Mice deficient for the neuronal glycine transporter subtype 2 (GlyT2) die during the second postnatal week after developing neuromotor deficiencies, which resembles severe forms of human hyperekplexia. This phenotype has been attributed to a dramatic reduction in glycinergic neurotransmission. In the present study we analyzed the development of GABAergic and glycinergic synaptic transmission in GlyT2-knockout mice during early postnatal life. Anti-glycine immunohistochemistry in spinal cord and brainstem slices and whole-cell voltage-clamp recordings of glycinergic inhibitory postsynaptic currents (IPSCs) from hypoglossal motoneurons revealed strikingly reduced levels of synaptic glycine already at birth. Since GABA and glycine use the same vesicular inhibitory amino acid transporter (VIAAT or VGAT) we also analysed GABAergic neurotransmission. No increase of GABA immunoreactivity was observed in the spinal cord and brainstem of GlyT2(-/-) mice at any stage of postnatal development. Correspondingly no up-regulation of GABAergic IPSCs was detected in GlyT2(-/-) hypoglossal motoneurons. These data suggest that in the first postnatal week, loss of the glycine transporter 2 is neither compensated by glycine de-novo synthesis nor by up-regulation of the GABAergic transmission in GlyT2(-/-) mice.
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Affiliation(s)
- A Tobias Latal
- Dept. Neuro- and Sensory Physiology, Center Physiology and Pathophysiology, Georg-August-University Göttingen, Humboldtallee 23, D-37073 Göttingen, Germany
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Zschüntzsch J, Hülsmann S, Schnell C, Dibaj P, Neusch C. Pharmacological modification of ATP-dependent microglial activation in a disease model of ALS. KLIN NEUROPHYSIOL 2010. [DOI: 10.1055/s-0030-1251013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Härtel K, Schnell C, Hülsmann S. Astrocytic calcium signals induced by neuromodulators via functional metabotropic receptors in the ventral respiratory group of neonatal mice. Glia 2009; 57:815-27. [DOI: 10.1002/glia.20808] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Streckfuss-Bömeke K, Vlasov A, Hülsmann S, Yin D, Nayernia K, Engel W, Hasenfuss G, Guan K. Generation of functional neurons and glia from multipotent adult mouse germ-line stem cells. Stem Cell Res 2009; 2:139-54. [DOI: 10.1016/j.scr.2008.09.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 09/10/2008] [Accepted: 09/14/2008] [Indexed: 11/24/2022] Open
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Winter SM, Hirrlinger J, Kirchhoff F, Hülsmann S. Transgenic expression of fluorescent proteins in respiratory neurons. Respir Physiol Neurobiol 2007; 159:108-14. [PMID: 17616445 DOI: 10.1016/j.resp.2007.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [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: 04/20/2007] [Revised: 05/12/2007] [Accepted: 05/14/2007] [Indexed: 10/23/2022]
Abstract
We screened transgenic mouse lines with Thy1.2 promoter-induced expression of fluorescent proteins (FPs) for targeting of respiratory neuronal populations in the medulla oblongata. Respiratory neurons were found to be tagged by FPs within the ventral respiratory column (VRC), the pre-Bötzinger complex (preBötC) and the rostral ventral respiratory group (rVRG) interneurons. A subset of neurons in the preBötC, labeled with the enhanced yellow fluorescent protein (EYFP), showed inspiratory activity during whole cell recordings from rhythmic slice preparations. Additionally, a subpopulation of EYFP-labeled preBötC neurons expressed both NK1- and mu-opioid receptors. Furthermore, the spinal trigeminal nucleus, the lateral reticular nucleus (LRT) and the hypoglossal nucleus demonstrated intense EYFP expression whereas other regions of the medulla were devoid of neuronal EYFP labeling (e.g. the nucleus ambiguous). In conclusion, Thy1.2-FP transgenic mice will facilitate the functional analysis of respiratory-related neurons in the medulla and improve the three dimensional analysis of cells contributing to this important neuronal circuit.
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Affiliation(s)
- Stefan M Winter
- Department of Neuro- and Sensory Physiology, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
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Härtel K, Singaravelu K, Kaiser M, Neusch C, Hülsmann S, Deitmer JW. Calcium influx mediated by the inwardly rectifying K+ channel Kir4.1 (KCNJ10) at low external K+ concentration. Cell Calcium 2007; 42:271-80. [PMID: 17284334 DOI: 10.1016/j.ceca.2006.12.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [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: 07/31/2006] [Revised: 11/10/2006] [Accepted: 12/14/2006] [Indexed: 10/23/2022]
Abstract
COS-1 cells with heterologeous expression of the Kir4.1 (KCNJ10) channel subunit, possess functional Kir4.1 channels and become capable to generating cytosolic Ca2+ transients, upon lowering of the extracellular K+ concentration to 2 mM or below. These Ca2+ transients are blocked by external Ba2+ (100 microM). Acute brain stem slices from wild-type mice (second post-natal week), which were loaded with the fluorescent Ca2+ indicator Oregon Green BAPTA-1-AM, were exposed to 0.2 mM K+. Under these conditions astrocytes, but not neurons, responded with cytosolic Ca2+ elevations in wild-type mice. This astrocyte-specific response has previously been used to identify astroglial cells type [R. Dallwig, H. Vitten, J.W. Deitmer, A novel barium-sensitive calcium influx into rat astrocytes at low external potassium. Cell Calcium 28 (2000) 247-259]. In Kir4.1 knock-out (Kir4.1-/-) mice, the number of responding cells was dramatically reduced and the Ca2+ transients in responding cells were significantly smaller than in wild-type mice. Our results indicate that Kir4.1 channels are the molecular substrate for the observed Ca2+ influx in astrocytes under conditions of low external K+-concentration.
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Affiliation(s)
- Kai Härtel
- Department of Neuro- and Sensory Physiology, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
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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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Manzke T, Preusse S, Hülsmann S, Richter DW. Developmental changes of serotonin 4(a) receptor expression in the rat pre-Bötzinger complex. J Comp Neurol 2007; 506:775-90. [DOI: 10.1002/cne.21581] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hirzel K, Müller U, Latal AT, Hülsmann S, Grudzinska J, Seeliger MW, Betz H, Laube B. Hyperekplexia Phenotype of Glycine Receptor α1 Subunit Mutant Mice Identifies Zn2+ as an Essential Endogenous Modulator of Glycinergic Neurotransmission. Neuron 2006; 52:679-90. [PMID: 17114051 DOI: 10.1016/j.neuron.2006.09.035] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [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: 03/23/2006] [Revised: 08/08/2006] [Accepted: 09/18/2006] [Indexed: 01/09/2023]
Abstract
Zn(2+) is thought to modulate neurotransmission by affecting currents mediated by ligand-gated ion channels and transmitter reuptake by Na(+)-dependent transporter systems. Here, we examined the in vivo relevance of Zn(2+) neuromodulation by producing knockin mice carrying the mutation D80A in the glycine receptor (GlyR) alpha1 subunit gene (Glra1). This substitution selectively eliminates the potentiating effect of Zn(2+) on GlyR currents. Mice homozygous for Glra1(D80A) develop a severe neuromotor phenotype postnatally that resembles forms of human hyperekplexia (startle disease) caused by mutations in GlyR genes. In spinal neurons and brainstem slices from Glra1(D80A) mice, GlyR expression, synaptic localization, and basal glycinergic transmission were normal; however, potentiation of spontaneous glycinergic currents by Zn(2+) was significantly impaired. Thus, the hyperekplexia phenotype of Glra1(D80A) mice is due to the loss of Zn(2+) potentiation of alpha1 subunit containing GlyRs, indicating that synaptic Zn(2+) is essential for proper in vivo functioning of glycinergic neurotransmission.
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Affiliation(s)
- Klaus Hirzel
- Abteilung Neurochemie, Max-Planck-Institut für Hirnforschung, Deutschordenstrasse 46, 60528 Frankfurt am Main, Germany
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