26
|
Berini SE, Low PA, Singer W. Pure Autonomic Failure – Predictors of Conversion to Clinical CNS Involvement. Auton Neurosci 2015. [DOI: 10.1016/j.autneu.2015.07.443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
27
|
Chumak T, Rüttiger L, Lee SC, Campanelli D, Zuccotti A, Singer W, Popelář J, Gutsche K, Geisler HS, Schraven SP, Jaumann M, Panford-Walsh R, Hu J, Schimmang T, Zimmermann U, Syka J, Knipper M. BDNF in Lower Brain Parts Modifies Auditory Fiber Activity to Gain Fidelity but Increases the Risk for Generation of Central Noise After Injury. Mol Neurobiol 2015; 53:5607-27. [PMID: 26476841 PMCID: PMC5012152 DOI: 10.1007/s12035-015-9474-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 10/05/2015] [Indexed: 11/24/2022]
Abstract
For all sensory organs, the establishment of spatial and temporal cortical resolution is assumed to be initiated by the first sensory experience and a BDNF-dependent increase in intracortical inhibition. To address the potential of cortical BDNF for sound processing, we used mice with a conditional deletion of BDNF in which Cre expression was under the control of the Pax2 or TrkC promoter. BDNF deletion profiles between these mice differ in the organ of Corti (BDNFPax2-KO) versus the auditory cortex and hippocampus (BDNFTrkC-KO). We demonstrate that BDNFPax2-KO but not BDNFTrkC-KO mice exhibit reduced sound-evoked suprathreshold ABR waves at the level of the auditory nerve (wave I) and inferior colliculus (IC) (wave IV), indicating that BDNF in lower brain regions but not in the auditory cortex improves sound sensitivity during hearing onset. Extracellular recording of IC neurons of BDNFPax2 mutant mice revealed that the reduced sensitivity of auditory fibers in these mice went hand in hand with elevated thresholds, reduced dynamic range, prolonged latency, and increased inhibitory strength in IC neurons. Reduced parvalbumin-positive contacts were found in the ascending auditory circuit, including the auditory cortex and hippocampus of BDNFPax2-KO, but not of BDNFTrkC-KO mice. Also, BDNFPax2-WT but not BDNFPax2-KO mice did lose basal inhibitory strength in IC neurons after acoustic trauma. These findings suggest that BDNF in the lower parts of the auditory system drives auditory fidelity along the entire ascending pathway up to the cortex by increasing inhibitory strength in behaviorally relevant frequency regions. Fidelity and inhibitory strength can be lost following auditory nerve injury leading to diminished sensory outcome and increased central noise.
Collapse
|
28
|
Knipper M, Panford-Walsh R, Singer W, Rüttiger L, Zimmermann U. Specific synaptopathies diversify brain responses and hearing disorders: you lose the gain from early life. Cell Tissue Res 2015; 361:77-93. [PMID: 25843689 PMCID: PMC4487345 DOI: 10.1007/s00441-015-2168-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/05/2015] [Indexed: 01/08/2023]
Abstract
Before hearing onset, inner hair cell (IHC) maturation proceeds under the influence of spontaneous Ca(2+) action potentials (APs). The temporal signature of the IHC Ca(2+) AP is modified through an efferent cholinergic feedback from the medial olivocochlear bundle (MOC) and drives the IHC pre- and post-synapse phenotype towards low spontaneous (spike) rate (SR), high-threshold characteristics. With sensory experience, the IHC pre- and post-synapse phenotype matures towards the instruction of low-SR, high-threshold and of high-SR, low-threshold auditory fiber characteristics. Corticosteroid feedback together with local brain-derived nerve growth factor (BDNF) and catecholaminergic neurotransmitters (dopamine) might be essential for this developmental step. In this review, we address the question of whether the control of low-SR and high-SR fiber characteristics is linked to various degrees of vulnerability of auditory fibers in the mature system. In particular, we examine several IHC synaptopathies in the context of various hearing disorders and exemplified shortfalls before and after hearing onset.
Collapse
|
29
|
Bing D, Lee SC, Campanelli D, Xiong H, Matsumoto M, Panford-Walsh R, Wolpert S, Praetorius M, Zimmermann U, Chu H, Knipper M, Rüttiger L, Singer W. Cochlear NMDA Receptors as a Therapeutic Target of Noise-Induced Tinnitus. Cell Physiol Biochem 2015; 35:1905-23. [DOI: 10.1159/000374000] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2015] [Indexed: 11/19/2022] Open
Abstract
Background: Accumulating evidence suggests that tinnitus may occur despite normal auditory sensitivity, probably linked to partial degeneration of the cochlear nerve and damage of the inner hair cell (IHC) synapse. Damage to the IHC synapses and deafferentation may occur even after moderate noise exposure. For both salicylate- and noise-induced tinnitus, aberrant N-methyl-d-aspartate (NMDA) receptor activation and related auditory nerve excitation have been suggested as origin of cochlear tinnitus. Accordingly, NMDA receptor inhibition has been proposed as a pharmacologic approach for treatment of synaptopathic tinnitus. Methods: Round-window application of the NMDA receptor antagonist AM-101 (Esketamine hydrochloride gel; Auris Medical AG, Basel, Switzerland) was tested in an animal model of tinnitus induced by acute traumatic noise. The study included the quantification of IHC ribbon synapses as a correlate for deafferentation as well as the measurement of the auditory brainstem response (ABR) to close-threshold sensation level stimuli as an indication of sound-induced auditory nerve activity. Results: We have shown that AM-101 reduced the trauma-induced loss of IHC ribbons and counteracted the decline of ABR wave I amplitude generated in the cochlea/auditory nerve. Conclusion: Local round-window application of AM-101 may be a promising therapeutic intervention for the treatment of synaptopathic tinnitus.
Collapse
|
30
|
Singer W, Joyner MJ, Sandroni P, Benarroch EE, Fealey RD, Mandrekar J, Low PA. Midodrine efficacy in orthostatic hypotension. J Gen Intern Med 2014; 29:1440-1. [PMID: 25200062 PMCID: PMC4238194 DOI: 10.1007/s11606-014-3014-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
31
|
Zuccotti A, Lee SC, Campanelli D, Singer W, Satheesh SV, Patriarchi T, Geisler HS, Köpschall I, Rohbock K, Nothwang HG, Hu J, Hell JW, Schimmang T, Rüttiger L, Knipper M. L-type CaV1.2 deletion in the cochlea but not in the brainstem reduces noise vulnerability: implication for CaV1.2-mediated control of cochlear BDNF expression. Front Mol Neurosci 2013; 6:20. [PMID: 23950737 PMCID: PMC3739414 DOI: 10.3389/fnmol.2013.00020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 07/20/2013] [Indexed: 01/24/2023] Open
Abstract
Voltage-gated L-type Ca2+ channels (L-VGCCs) like CaV1.2 are assumed to play a crucial role for controlling release of trophic peptides including brain-derived neurotrophic factor (BDNF). In the inner ear of the adult mouse, besides the well-described L-VGCC CaV1.3, CaV1.2 is also expressed. Due to lethality of constitutive CaV1.2 knock-out mice, the function of this ion channel as well as its putative relationship to BDNF in the auditory system is entirely elusive. We recently described that BDNF plays a differential role for inner hair cell (IHC) vesicles release in normal and traumatized condition. To elucidate a presumptive role of CaV1.2 during this process, two tissue-specific conditional mouse lines were generated. To distinguish the impact of CaV1.2 on the cochlea from that on feedback loops from higher auditory centers CaV1.2 was deleted, in one mouse line, under the Pax2 promoter (CaV1.2Pax2) leading to a deletion in the spiral ganglion neurons, dorsal cochlear nucleus, and inferior colliculus. In the second mouse line, the Egr2 promoter was used for deleting CaV1.2 (CaV1.2Egr2) in auditory brainstem nuclei. In both mouse lines, normal hearing threshold and equal number of IHC release sites were observed. We found a slight reduction of auditory brainstem response wave I amplitudes in the CaV1.2Pax2 mice, but not in the CaV1.2Egr2 mice. After noise exposure, CaV1.2Pax2 mice had less-pronounced hearing loss that correlated with maintenance of ribbons in IHCs and less reduced activity in auditory nerve fibers, as well as in higher brain centers at supra-threshold sound stimulation. As reduced cochlear BDNF mRNA levels were found in CaV1.2Pax2 mice, we suggest that a CaV1.2-dependent step may participate in triggering part of the beneficial and deteriorating effects of cochlear BDNF in intact systems and during noise exposure through a pathway that is independent of CaV1.2 function in efferent circuits.
Collapse
|
32
|
Singer W, Robertson D, Gilman S, Kaufmann H, Biaggioni I, Freeman R, Fealey R, Mandrekar J, Dupont W, Gehrking T, Schmelzer J, Sletten D, Gehrking J, Low P. Randomized Trial of Rifampicin in MSA: Primary Outcomes and Effect on Autonomic Function. Auton Neurosci 2013. [DOI: 10.1016/j.autneu.2013.05.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
33
|
Bergmann J, Genc E, Kohler A, Singer W, Pearson J. Anatomy of early visual cortex predicts visual working memory capacity. J Vis 2013. [DOI: 10.1167/13.9.1349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
34
|
Singer W, Panford-Walsh R, Knipper M. The function of BDNF in the adult auditory system. Neuropharmacology 2013; 76 Pt C:719-28. [PMID: 23688926 DOI: 10.1016/j.neuropharm.2013.05.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/03/2013] [Accepted: 05/06/2013] [Indexed: 02/06/2023]
Abstract
The inner ear of vertebrates is specialized to perceive sound, gravity and movements. Each of the specialized sensory organs within the cochlea (sound) and vestibular system (gravity, head movements) transmits information to specific areas of the brain. During development, brain-derived neurotrophic factor (BDNF) orchestrates the survival and outgrowth of afferent fibers connecting the vestibular organ and those regions in the cochlea that map information for low frequency sound to central auditory nuclei and higher-auditory centers. The role of BDNF in the mature inner ear is less understood. This is mainly due to the fact that constitutive BDNF mutant mice are postnatally lethal. Only in the last few years has the improved technology of performing conditional cell specific deletion of BDNF in vivo allowed the study of the function of BDNF in the mature developed organ. This review provides an overview of the current knowledge of the expression pattern and function of BDNF in the peripheral and central auditory system from just prior to the first auditory experience onwards. A special focus will be put on the differential mechanisms in which BDNF drives refinement of auditory circuitries during the onset of sensory experience and in the adult brain. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
Collapse
|
35
|
Singer W, Geisler HS, Knipper M. The Geisler method: tracing activity-dependent cGMP plasticity changes upon double detection of mRNA and protein on brain slices. Methods Mol Biol 2013; 1020:223-33. [PMID: 23709037 DOI: 10.1007/978-1-62703-459-3_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We recently demonstrated that an increase of guanosine 3',5'-cyclic monophosphate (cGMP) signaling could protect the inner ear from noise-induced hair cell damage. Noise exposure not only damages hair cells but also alters the central responsiveness to sound leading to plasticity changes. cGMP signaling has long been known to play a crucial role for plasticity changes and long-term potentiation (LTP). To get a first insight into the role of cGMP for noise-induced plasticity changes we aimed to co-trace the mRNA and protein of plasticity-related genes as, e.g., the immediate early gene Arc (activity-regulated cytoskeletal protein) with markers for the cGMP pathway. We developed a method that permits the simultaneous monitoring of mRNA and protein through light microscopy to visualize gene expression in neurons and synapses of its processes. Accordingly, different from previous fluorescence-based assays that detect, e.g., fluorochrome-labeled Arc antibodies and Arc mRNA, we describe here a methodology that allows the detection of mRNA and protein of synaptic genes using nonfluorescent stable tracers for high-resolution observation of activity-dependent plasticity changes using light microscopy even after weeks or months.
Collapse
|
36
|
Eckrich T, Varakina K, Johnson SL, Franz C, Singer W, Kuhn S, Knipper M, Holley MC, Marcotti W. Development and function of the voltage-gated sodium current in immature mammalian cochlear inner hair cells. PLoS One 2012; 7:e45732. [PMID: 23029208 PMCID: PMC3446918 DOI: 10.1371/journal.pone.0045732] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 08/14/2012] [Indexed: 12/19/2022] Open
Abstract
Inner hair cells (IHCs), the primary sensory receptors of the mammalian cochlea, fire spontaneous Ca2+ action potentials before the onset of hearing. Although this firing activity is mainly sustained by a depolarizing L-type (CaV1.3) Ca2+ current (ICa), IHCs also transiently express a large Na+ current (INa). We aimed to investigate the specific contribution of INa to the action potentials, the nature of the channels carrying the current and whether the biophysical properties of INa differ between low- and high-frequency IHCs. We show that INa is highly temperature-dependent and activates at around −60 mV, close to the action potential threshold. Its size was larger in apical than in basal IHCs and between 5% and 20% should be available at around the resting membrane potential (−55 mV/−60 mV). However, in vivo the availability of INa could potentially increase to >60% during inhibitory postsynaptic potential activity, which transiently hyperpolarize IHCs down to as far as −70 mV. When IHCs were held at −60 mV and INa elicited using a simulated action potential as a voltage command, we found that INa contributed to the subthreshold depolarization and upstroke of an action potential. We also found that INa is likely to be carried by the TTX-sensitive channel subunits NaV1.1 and NaV1.6 in both apical and basal IHCs. The results provide insight into how the biophysical properties of INa in mammalian cochlear IHCs could contribute to the spontaneous physiological activity during cochlear maturation in vivo.
Collapse
|
37
|
Klein C, Figueroa J, Snyder M, Bryant S, Balsanek J, Dyck PJB, Dyck P, Staff N, Singer W, Low P, Sandroni P, Mauermann M, Tracy J. Cytokine Multiplex Testing in Clinical Evaluation of Peripheral Neuropathies (P05.151). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.p05.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
38
|
Singer W, Klein C, McKeon A, Low P. Autoimmune Autonomic Ganglionopathy Associated with Voltage-Gated Potassium Channel Antibodies (P05.209). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.p05.209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
39
|
Singer W, Gehrking T, Gehrking J, Sletten D, Figueroa J, Sandroni P, Low P. 3,4 Diaminopyridine - A Promising Novel Treatment Approach to Orthostatic Hypotension (P05.204). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.p05.204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
40
|
Park K, Singer W, Opfer-Gehrking T, Sletten D, Figueroa J, Zeller A, Low P. Neuropathic vs hyperadrenergic POTS: time and frequency domain analysis. Auton Neurosci 2011. [DOI: 10.1016/j.autneu.2011.05.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
41
|
Singer W, Opfer-Gehrking T, Gehrking J, Figueroa J, Sandroni P, Low P. 3,4 Diaminopyridine improves orthostatic blood pressure and symptoms in neurogenic orthostatic hypotension. Auton Neurosci 2011. [DOI: 10.1016/j.autneu.2011.05.178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
42
|
Singer W, Yung IO, Wollmann R, Kelly T, Keegan BM. A middle-aged woman with nausea, weight loss, and orthostatic hypotension. Neurology 2011; 77:489-95. [PMID: 21810698 DOI: 10.1212/wnl.0b013e318227b18a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
43
|
Hoffmann P, Rapp M, Singer W, Keuer D. Trends of mesospheric gravity waves at northern middle latitudes during summer. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd015717] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
44
|
Andreasson J, Iwan B, Andrejczuk A, Abreu E, Bergh M, Caleman C, Nelson AJ, Bajt S, Chalupsky J, Chapman HN, Fäustlin RR, Hajkova V, Heimann PA, Hjörvarsson B, Juha L, Klinger D, Krzywinski J, Nagler B, Pálsson GK, Singer W, Seibert MM, Sobierajski R, Toleikis S, Tschentscher T, Vinko SM, Lee RW, Hajdu J, Tîmneanu N. Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:016403. [PMID: 21405780 DOI: 10.1103/physreve.83.016403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 11/25/2010] [Indexed: 05/30/2023]
Abstract
Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 10(17) W/cm(2) were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 10(16) W/cm(2). This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.
Collapse
|
45
|
Weigelt S, Pohl K, Singer W, Kohler A. Orientation-selective fMRI adaptation in primary visual cortex revisited. J Vis 2010. [DOI: 10.1167/10.7.914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
46
|
Lee HS, van Stijn S, Schwalm M, Singer W, Kohler A. Brain areas involved in perception of motion in depth: a human fMRI study. J Vis 2010. [DOI: 10.1167/10.7.813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
47
|
Sireteanu R, Oertel V, Mohr H, Haenschel C, Linden D, Maurer K, Singer W, Schwarz M. Graphical illustration and functional neuroimaging of visual hallucinations during prolonged blindfolding: A comparison to visual imagery. J Vis 2010. [DOI: 10.1167/8.6.68] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
48
|
Galuske RAW, Singer W, Munk MMHJ. Cortical states determine the polarity of orientation plasticity in primary visual cortex. J Vis 2010. [DOI: 10.1167/6.6.403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
49
|
Rodriguez R, Kallenbach U, Singer W, Munk M. Stabilization of visual responses through cholinergic activation. Neuroscience 2010; 165:944-54. [DOI: 10.1016/j.neuroscience.2009.10.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 10/27/2009] [Accepted: 10/28/2009] [Indexed: 11/25/2022]
|
50
|
Schwiedrzik CM, Singer W, Melloni L. Sensitivity and perceptual awareness increase with practice in metacontrast masking. J Vis 2009; 9:18.1-18. [DOI: 10.1167/9.10.18] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|