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Castagnola T, Castagna VC, Kitcher SR, Torres Cadenas L, Di Guilmi MN, Gomez Casati ME, Buonfiglio PI, Dalamón V, Katz E, Elgoyhen AB, Weisz CJ, Goutman JD, Wedemeyer C. Co-release of GABA and ACh from medial olivocochlear neurons fine tunes cochlear efferent inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.12.607644. [PMID: 39185230 PMCID: PMC11343139 DOI: 10.1101/2024.08.12.607644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
During development, inner hair cells (IHCs) in the mammalian cochlea are unresponsive to acoustic stimuli but instead exhibit spontaneous activity. During this same period, neurons originating from the medial olivocochlear complex (MOC) transiently innervate IHCs, regulating their firing pattern which is crucial for the correct development of the auditory pathway. Although the MOC-IHC is a cholinergic synapse, previous evidence indicates the widespread presence of gamma-aminobutyric acid (GABA) signaling markers, including presynaptic GABAB receptors (GABABR). In this study, we explore the source of GABA by optogenetically activating either cholinergic or GABAergic fibers. The optogenetic stimulation of MOC terminals from GAD;ChR2-eYFP and ChAT;ChR2-eYFP mice evoked synaptic currents in IHCs that were blocked by α-bungarotoxin. This suggests that GABAergic fibers release ACh and activate α9α10 nicotinic acetylcholine receptors (nAChRs). Additionally, MOC cholinergic fibers release not only ACh but also GABA, as the effect of GABA on ACh response amplitude was prevented by applying the GABAB-R blocker (CGP 36216). Using optical neurotransmitter detection and calcium imaging techniques, we examined the extent of GABAergic modulation at the single synapse level. Our findings suggest heterogeneity in GABA modulation, as only 15 out of 31 recorded synaptic sites were modulated by applying the GABABR specific antagonist, CGP (100-200 μM). In conclusion, we provide compelling evidence that GABA and ACh are co-released from at least a subset of MOC terminals. In this circuit, GABA functions as a negative feedback mechanism, locally regulating the extent of cholinergic inhibition at certain efferent-IHC synapses during an immature stage.
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Affiliation(s)
- Tais Castagnola
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
| | - Valeria C Castagna
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, (1121) Ciudad Autónoma de Buenos Aires, Argentina
| | - Siân R. Kitcher
- Section on Neuronal Circuitry, National Institutes of Health, National Institute on Deafness and Other Communication Disorders, Bethesda, MD 20892, USA
| | - Lester Torres Cadenas
- Section on Neuronal Circuitry, National Institutes of Health, National Institute on Deafness and Other Communication Disorders, Bethesda, MD 20892, USA
| | - Mariano N Di Guilmi
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
| | - Maria Eugenia Gomez Casati
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, (1121) Ciudad Autónoma de Buenos Aires, Argentina
| | - Paula I Buonfiglio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
| | - Viviana Dalamón
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
| | - Eleonora Katz
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad Universitaria (C1428EGA) Ciudad Autónoma de Buenos Aires, Argentina
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, (1121) Ciudad Autónoma de Buenos Aires, Argentina
| | - Catherine J.C. Weisz
- Section on Neuronal Circuitry, National Institutes of Health, National Institute on Deafness and Other Communication Disorders, Bethesda, MD 20892, USA
| | - Juan D Goutman
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
| | - Carolina Wedemeyer
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas, (1428) Ciudad Autónoma de Buenos Aires, Argentina
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Kersbergen CJ, Bergles DE. Priming central sound processing circuits through induction of spontaneous activity in the cochlea before hearing onset. Trends Neurosci 2024; 47:522-537. [PMID: 38782701 PMCID: PMC11236524 DOI: 10.1016/j.tins.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/02/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024]
Abstract
Sensory systems experience a period of intrinsically generated neural activity before maturation is complete and sensory transduction occurs. Here we review evidence describing the mechanisms and functions of this 'spontaneous' activity in the auditory system. Both ex vivo and in vivo studies indicate that this correlated activity is initiated by non-sensory supporting cells within the developing cochlea, which induce depolarization and burst firing of groups of nearby hair cells in the sensory epithelium, activity that is conveyed to auditory neurons that will later process similar sound features. This stereotyped neural burst firing promotes cellular maturation, synaptic refinement, acoustic sensitivity, and establishment of sound-responsive domains in the brain. While sensitive to perturbation, the developing auditory system exhibits remarkable homeostatic mechanisms to preserve periodic burst firing in deaf mice. Preservation of this early spontaneous activity in the context of deafness may enhance the efficacy of later interventions to restore hearing.
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Affiliation(s)
- Calvin J Kersbergen
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
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3
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Ma X, Guo J, Fu Y, Shen C, Jiang P, Zhang Y, Zhang L, Yu Y, Fan J, Chai R. G protein-coupled receptors in cochlea: Potential therapeutic targets for hearing loss. Front Mol Neurosci 2022; 15:1028125. [PMID: 36311029 PMCID: PMC9596917 DOI: 10.3389/fnmol.2022.1028125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022] Open
Abstract
The prevalence of hearing loss-related diseases caused by different factors is increasing worldwide year by year. Currently, however, the patient’s hearing loss has not been effectively improved. Therefore, there is an urgent need to adopt new treatment measures and treatment techniques to help improve the therapeutic effect of hearing loss. G protein-coupled receptors (GPCRs), as crucial cell surface receptors, can widely participate in different physiological and pathological processes, particularly play an essential role in many disease occurrences and be served as promising therapeutic targets. However, no specific drugs on the market have been found to target the GPCRs of the cochlea. Interestingly, many recent studies have demonstrated that GPCRs can participate in various pathogenic process related to hearing loss in the cochlea including heredity, noise, ototoxic drugs, cochlear structure, and so on. In this review, we comprehensively summarize the functions of 53 GPCRs known in the cochlea and their relationships with hearing loss, and highlight the recent advances of new techniques used in cochlear study including cryo-EM, AI, GPCR drug screening, gene therapy vectors, and CRISPR editing technology, as well as discuss in depth the future direction of novel GPCR-based drug development and gene therapy for cochlear hearing loss. Collectively, this review is to facilitate basic and (pre-) clinical research in this area, and provide beneficial help for emerging GPCR-based cochlear therapies.
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Affiliation(s)
- Xiangyu Ma
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Jiamin Guo
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yaoyang Fu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Cangsong Shen
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Jiang
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
| | - Yuan Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
- Research Institute of Otolaryngology, Nanjing, China
| | - Lei Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, The Second Hospital of Anhui Medical University, Hefei, China
| | - Yafeng Yu
- First Affiliated Hospital of Soochow University, Soochow, China
- *Correspondence: Yafeng Yu,
| | - Jiangang Fan
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Jiangang Fan,
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
- Renjie Chai,
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Boero LE, Payne S, Gómez-Casati ME, Rutherford MA, Goutman JD. Noise Exposure Potentiates Exocytosis From Cochlear Inner Hair Cells. Front Synaptic Neurosci 2021; 13:740368. [PMID: 34658832 PMCID: PMC8511412 DOI: 10.3389/fnsyn.2021.740368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/10/2021] [Indexed: 11/19/2022] Open
Abstract
Noise-induced hearing loss has gained relevance as one of the most common forms of hearing impairment. The anatomical correlates of hearing loss, principally cell damage and/or death, are relatively well-understood histologically. However, much less is known about the physiological aspects of damaged, surviving cells. Here we addressed the functional consequences of noise exposure on the capacity of inner hair cells (IHCs) to release synaptic vesicles at synapses with spiral ganglion neurons (SGNs). Mice of either sex at postnatal day (P) 15–16 were exposed to 1–12 kHz noise at 120 dB sound pressure level (SPL), for 1 h. Exocytosis was measured by tracking changes in membrane capacitance (ΔCm) from IHCs of the apical cochlea. Upon IHC depolarization to different membrane potentials, ΔCm showed the typical bell-shaped curve that mirrors the voltage dependence of Ca2+ influx, in both exposed and unexposed cells. Surprisingly, from IHCs at 1-day after exposure (d.a.e.), we found potentiation of exocytosis at the peak of the bell-shaped curve. The increase in exocytosis was not accompanied by changes in whole-cell Ca2+ influx, suggesting a modification in coupling between Ca2+ channels and synaptic vesicles. Consistent with this notion, noise exposure also changed the Ca2+-dependence of exocytosis from linear to supralinear. Noise exposure did not cause loss of IHCs, but did result in a small reduction in the number of IHC-SGN synapses at 1-d.a.e. which recovered by 14-d.a.e. In contrast, a strong reduction in auditory brainstem response wave-I amplitude (representing synchronous firing of SGNs) and distortion product otoacoustic emissions (reflecting outer hair cell function) indicated a profound hearing loss at 1- and 14-d.a.e. To determine the role of glutamate release in the noise-induced potentiation of exocytosis, we evaluated vesicular glutamate transporter-3 (Vglut3) knock-out (KO) mice. Unlike WT, IHCs from Vglut3KO mice showed a noise-induced reduction in ΔCm and Ca2+ influx with no change in the Ca2+-dependence of exocytosis. Together, these results indicate that traumatic noise exposure triggers changes of IHC synaptic function including a Vglut3-dependent potentiation of exocytosis.
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Affiliation(s)
- Luis E Boero
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Buenos Aires, Argentina.,Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Shelby Payne
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
| | | | - Mark A Rutherford
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
| | - Juan D Goutman
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Buenos Aires, Argentina
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Kitcher SR, Pederson AM, Weisz CJC. Diverse identities and sites of action of cochlear neurotransmitters. Hear Res 2021; 419:108278. [PMID: 34108087 DOI: 10.1016/j.heares.2021.108278] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/30/2021] [Accepted: 05/18/2021] [Indexed: 11/18/2022]
Abstract
Accurate encoding of acoustic stimuli requires temporally precise responses to sound integrated with cellular mechanisms that encode the complexity of stimuli over varying timescales and orders of magnitude of intensity. Sound in mammals is initially encoded in the cochlea, the peripheral hearing organ, which contains functionally specialized cells (including hair cells, afferent and efferent neurons, and a multitude of supporting cells) to allow faithful acoustic perception. To accomplish the demanding physiological requirements of hearing, the cochlea has developed synaptic arrangements that operate over different timescales, with varied strengths, and with the ability to adjust function in dynamic hearing conditions. Multiple neurotransmitters interact to support the precision and complexity of hearing. Here, we review the location of release, action, and function of neurotransmitters in the mammalian cochlea with an emphasis on recent work describing the complexity of signaling.
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Affiliation(s)
- Siân R Kitcher
- Section on Neuronal Circuitry, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, United States
| | - Alia M Pederson
- Section on Neuronal Circuitry, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, United States
| | - Catherine J C Weisz
- Section on Neuronal Circuitry, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, United States.
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Reijntjes DOJ, Breitzler JL, Persic D, Pyott SJ. Preparation of the intact rodent organ of Corti for RNAscope and immunolabeling, confocal microscopy, and quantitative analysis. STAR Protoc 2021; 2:100544. [PMID: 34195667 PMCID: PMC8233256 DOI: 10.1016/j.xpro.2021.100544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
This protocol describes the preparation of the mouse organ of Corti for RNAscope, immunolabeling, confocal microscopy, and quantitative image analysis to examine transcript and protein localization, sensory hair cells, and synapses. This protocol can be applied to mice and other rodents (juvenile and adult) and can be adapted for other techniques, including electrophysiology and RNA sequencing. This protocol features minimal tissue processing to preserve viability for downstream assays, while isolating the organ of Corti is the most challenging step. For additional details on the use and execution of this protocol, please refer to McLean et al. (2009); Schuth et al. (2014); Lingle et al. (2019); Pyott et al. (2020).
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Affiliation(s)
- Daniel O J Reijntjes
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MA 21201, USA
| | - J Lukas Breitzler
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, the Netherlands
| | - Dora Persic
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, the Netherlands
| | - Sonja J Pyott
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, the Netherlands
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Vyas P, Wood MB, Zhang Y, Goldring AC, Chakir FZ, Fuchs PA, Hiel H. Characterization of HA-tagged α9 and α10 nAChRs in the mouse cochlea. Sci Rep 2020; 10:21814. [PMID: 33311584 PMCID: PMC7733449 DOI: 10.1038/s41598-020-78380-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 11/20/2020] [Indexed: 01/02/2023] Open
Abstract
Neurons of the medial olivary complex inhibit cochlear hair cells through the activation of α9α10-containing nicotinic acetylcholine receptors (nAChRs). Efforts to study the localization of these proteins have been hampered by the absence of reliable antibodies. To overcome this obstacle, CRISPR-Cas9 gene editing was used to generate mice in which a hemagglutinin tag (HA) was attached to the C-terminus of either α9 or α10 proteins. Immunodetection of the HA tag on either subunit in the organ of Corti of adult mice revealed immunopuncta clustered at the synaptic pole of outer hair cells. These puncta were juxtaposed to immunolabeled presynaptic efferent terminals. HA immunopuncta also occurred in inner hair cells of pre-hearing (P7) but not in adult mice. These immunolabeling patterns were similar for both homozygous and heterozygous mice. All HA-tagged genotypes had auditory brainstem responses not significantly different from those of wild type littermates. The activation of efferent neurons in heterozygous mice evoked biphasic postsynaptic currents not significantly different from those of wild type hair cells. However, efferent synaptic responses were significantly smaller and less frequent in the homozygous mice. We show that HA-tagged nAChRs introduced in the mouse by a CRISPR knock-in are regulated and expressed like the native protein, and in the heterozygous condition mediate normal synaptic function. The animals thus generated have clear advantages for localization studies.
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Affiliation(s)
- Pankhuri Vyas
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA
| | - Megan Beers Wood
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA
| | - Yuanyuan Zhang
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA.,Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Adam C Goldring
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA.,Sutter Instrument Company, 1 Digital Drive, Novato, CA, 94949, USA
| | - Fatima-Zahra Chakir
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA
| | - Paul Albert Fuchs
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA
| | - Hakim Hiel
- The Center for Hearing and Balance, Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 818, Baltimore, MD, 21205, USA.
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9
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Cochlear homeostasis: a molecular physiological perspective on maintenance of sound transduction and auditory neurotransmission with noise and ageing. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Ramakrishna Y, Manca M, Glowatzki E, Sadeghi SG. Cholinergic Modulation of Membrane Properties of Calyx Terminals in the Vestibular Periphery. Neuroscience 2020; 452:98-110. [PMID: 33197502 DOI: 10.1016/j.neuroscience.2020.10.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 01/10/2023]
Abstract
Vestibular nerve afferents are divided into regular and irregular groups based on the variability of interspike intervals in their resting discharge. Most afferents receive inputs from bouton terminals that contact type II hair cells as well as from calyx terminals that cover the basolateral walls of type I hair cells. Calyces have an abundance of different subtypes of KCNQ (Kv7) potassium channels and muscarinic acetylcholine receptors (mAChRs) and receive cholinergic efferent inputs from neurons in the brainstem. We investigated whether mAChRs affected membrane properties and firing patterns of calyx terminals through modulation of KCNQ channel activity. Patch clamp recordings were performed from calyx terminals in central regions of the cristae of the horizontal and anterior canals in 13-26 day old Sprague-Dawley rats. KCNQ mediated currents were observed as voltage sensitive currents with slow kinetics (activation and deactivation), resulting in spike frequency adaptation so that calyces at best fired a single action potential at the beginning of a depolarizing step. Activation of mAChRs by application of oxotremorine methiodide or inhibition of KCNQ channels by linopirdine dihydrochloride decreased voltage activated currents by ∼30%, decreased first spike latencies by ∼40%, resulted in action potential generation in response to smaller current injections and at lower (i.e., more hyperpolarized) membrane potentials, and increased the number of spikes fired during depolarizing steps. Interestingly, some of the calyces showed spontaneous discharge in the presence of these drugs. Together, these findings suggest that cholinergic efferents can modulate the response properties and encoding of head movements by afferents.
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Affiliation(s)
- Yugandhar Ramakrishna
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Department of Communication Disorders and Sciences, California State University, Northridge, CA, United States
| | - Marco Manca
- Department of Otolaryngology - Head and Neck Surgery, The Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Elisabeth Glowatzki
- Department of Otolaryngology - Head and Neck Surgery, The Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD, United States; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Soroush G Sadeghi
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, NY, United States; Neuroscience Program, State University of New York at Buffalo, Buffalo, NY, United States.
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11
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Kim WB, Kang KW, Sharma K, Yi E. Distribution of K v3 Subunits in Cochlear Afferent and Efferent Nerve Fibers Implies Distinct Role in Auditory Processing. Exp Neurobiol 2020; 29:344-355. [PMID: 33154197 PMCID: PMC7649084 DOI: 10.5607/en20043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 11/19/2022] Open
Abstract
Kv3 family K+ channels, by ensuring speedy repolarization of action potential, enable rapid and high frequency neuronal firing and high precision temporal coding of auditory information in various auditory synapses in the brain. Expression of different Kv3 subtypes within the auditory end organ has been reported. Yet, their precise role at the hair cell synaptic transmission has not been fully elucidated. Using immunolabeling and confocal microscopy we examined the expression pattern of different Kv3 family K+ channel subunits in the nerve fibers innervating the cochlear hair cells. Kv3.1b was found in NKA-positive type 1 afferent fibers, exhibiting high signal intensity at the cell body, the unmyelinated dendritic segment, first heminode and nodes of Ranvier. Kv3.3 signal was detected in the cell body and the unmyelinated dendritic segment of NKA-positive type 1 afferent fibers but not in peripherin-positive type 2 afferent. Kv3.4 was found in ChAT-positive LOC and MOC efferent fibers as well as peripherin-positive type 2 afferent fibers. Such segregated expression pattern implies that each Kv3 subunits participate in different auditory tasks, for example, Kv3.1b and Kv3.3 in ascending signaling while Kv3.4 in feedback upon loud noise exposure.
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Affiliation(s)
- Woo Bin Kim
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Kwon-Woo Kang
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Kushal Sharma
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Eunyoung Yi
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
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12
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Zhang Y, Glowatzki E, Roux I, Fuchs PA. Nicotine evoked efferent transmitter release onto immature cochlear inner hair cells. J Neurophysiol 2020; 124:1377-1387. [PMID: 32845208 DOI: 10.1152/jn.00097.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Olivocochlear neurons make temporary cholinergic synapses on inner hair cells of the rodent cochlea in the first 2 to 3 wk after birth. Repetitive stimulation of these efferent neurons causes facilitation of evoked release and increased spontaneous release that continues for seconds to minutes. Presynaptic nicotinic acetylcholine receptors (nAChRs) are known to modulate neurotransmitter release from brain neurons. The present study explores the hypothesis that presynaptic nAChRs help to increase spontaneous release from efferent terminals on cochlear hair cells. Direct application of nicotine (which does not activate the hair cells' α9α10-containing nAChRs) produces sustained efferent transmitter release, implicating presynaptic nAChRs in this response. The effect of nicotine was reduced by application of ryanodine that reduces release of calcium from intraterminal stores.NEW & NOTEWORTHY Sensory organs exhibit spontaneous activity before the onset of response to external stimuli. Such activity in the cochlea is subject to modulation by cholinergic efferent neurons that directly inhibit sensory hair cells (inner hair cells). Those efferent neurons are themselves subject to various modulatory mechanisms. One such mechanism is positive feedback by released acetylcholine onto presynaptic nicotinic acetylcholine receptors causing further release of acetylcholine.
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Affiliation(s)
- Y Zhang
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - E Glowatzki
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - I Roux
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Porter Neuroscience Research Center, Bethesda, Maryland
| | - P A Fuchs
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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13
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Dyhrfjeld-Johnsen J, Cederroth CR. Current Clinical Trials for Tinnitus. Otolaryngol Clin North Am 2020; 53:651-666. [DOI: 10.1016/j.otc.2020.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Abstract
Cholinergic efferent neurons originating in the brainstem innervate the acoustico-lateralis organs (inner ear, lateral line) of vertebrates. These release acetylcholine (ACh) to inhibit hair cells through activation of calcium-dependent potassium channels. In the mammalian cochlea, ACh shunts and suppresses outer hair cell (OHC) electromotility, reducing the essential amplification of basilar membrane motion. Consequently, medial olivocochlear neurons that inhibit OHCs reduce the sensitivity and frequency selectivity of afferent neurons driven by cochlear vibration of inner hair cells (IHCs). The cholinergic synapse on hair cells involves an unusual ionotropic ACh receptor, and a near-membrane postsynaptic cistern. Lateral olivocochlear (LOC) neurons modulate type I afferents by still-to-be-defined synaptic mechanisms. Olivocochlear neurons can be activated by a reflex arc that includes the auditory nerve and projections from the cochlear nucleus. They are also subject to modulation by higher-order central auditory interneurons. Through its actions on cochlear hair cells, afferent neurons, and higher centers, the olivocochlear system protects against age-related and noise-induced hearing loss, improves signal coding in noise under certain conditions, modulates selective attention to sensory stimuli, and influences sound localization.
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Affiliation(s)
- Paul Albert Fuchs
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2195
| | - Amanda M Lauer
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2195
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15
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Kearney G, Zorrilla de San Martín J, Vattino LG, Elgoyhen AB, Wedemeyer C, Katz E. Developmental Synaptic Changes at the Transient Olivocochlear-Inner Hair Cell Synapse. J Neurosci 2019; 39:3360-3375. [PMID: 30755493 PMCID: PMC6495135 DOI: 10.1523/jneurosci.2746-18.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/04/2019] [Accepted: 01/30/2019] [Indexed: 12/18/2022] Open
Abstract
In the mature mammalian cochlea, inner hair cells (IHCs) are mainly innervated by afferent fibers that convey sound information to the CNS. During postnatal development, however, medial olivocochlear (MOC) efferent fibers transiently innervate the IHCs. The MOC-IHC synapse, functional from postnatal day 0 (P0) to hearing onset (P12), undergoes dramatic changes in the sensitivity to acetylcholine (ACh) and in the expression of key postsynaptic proteins. To evaluate whether there are associated changes in the properties of ACh release during this period, we used a cochlear preparation from mice of either sex at P4, P6-P7, and P9-P11 and monitored transmitter release from MOC terminals in voltage-clamped IHCs in the whole-cell configuration. The quantum content increased 5.6× from P4 to P9-P11 due to increases in the size and replenishment rate of the readily releasable pool of synaptic vesicles without changes in their probability of release or quantum size. This strengthening in transmission was accompanied by changes in short-term plasticity properties, which switched from facilitation at P4 to depression at P9-P11. We have previously shown that at P9-P11, ACh release is supported by P/Q- and N-type voltage-gated calcium channels (VGCCs) and negatively regulated by BK potassium channels activated by Ca2+ influx through L-type VGCCs. We now show that at P4 and P6-P7, release is mediated by P/Q-, R- and L-type VGCCs. Interestingly, L-type VGCCs have a dual role: they both support release and fuel BK channels, suggesting that at immature stages presynaptic proteins involved in release are less compartmentalized.SIGNIFICANCE STATEMENT During postnatal development before the onset of hearing, cochlear inner hair cells (IHCs) present spontaneous Ca2+ action potentials that release glutamate at the first auditory synapse in the absence of sound stimulation. The IHC Ca2+ action potential frequency pattern, which is crucial for the correct establishment and function of the auditory system, is regulated by the efferent medial olivocochlear (MOC) system that transiently innervates IHCs during this period. We show here that developmental changes in synaptic strength and synaptic plasticity properties at the MOC-IHC synapse upon MOC fiber activation at different frequencies might be crucial for tightly shaping the pattern of afferent activity during this critical period.
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Affiliation(s)
- Graciela Kearney
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Ciudad Autónoma de Buenos Aires, Argentina
| | - Javier Zorrilla de San Martín
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Ciudad Autónoma de Buenos Aires, Argentina
| | - Lucas G Vattino
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Ciudad Autónoma de Buenos Aires, Argentina
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, 1121 Ciudad Autónoma de Buenos Aires, Argentina, and
| | - Carolina Wedemeyer
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Ciudad Autónoma de Buenos Aires, Argentina
| | - Eleonora Katz
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Ciudad Autónoma de Buenos Aires, Argentina,
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad Universitaria, C1428EGA Ciudad Autónoma de Buenos Aires, Argentina
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16
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Barone CM, Douma S, Reijntjes DOJ, Browe BM, Köppl C, Klump G, Park TJ, Pyott SJ. Altered cochlear innervation in developing and mature naked and Damaraland mole rats. J Comp Neurol 2019; 527:2302-2316. [PMID: 30861124 PMCID: PMC6767702 DOI: 10.1002/cne.24682] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 01/04/2023]
Abstract
Compared to many other rodent species, naked mole rats (Heterocephalus glaber) have elevated auditory thresholds, poor frequency selectivity, and limited ability to localize sound. Because the cochlea is responsible for encoding and relaying auditory signals to the brain, we used immunofluorescence and quantitative image analysis to examine cochlear innervation in mature and developing naked mole rats compared to mice (Mus musculus), gerbils (Meriones unguiculatus), and Damaraland mole rats (Fukomys damarensis), another subterranean rodent. In comparison to mice and gerbils, we observed alterations in afferent and efferent innervation as well as their patterns of developmental refinement in naked and Damaraland mole rats. These alterations were, however, not always shared similarly between naked and Damaraland mole rats. Most conspicuously, in both naked and Damaraland mole rats, inner hair cell (IHC) afferent ribbon density was reduced, whereas outer hair cell afferent ribbon density was increased. Naked and Damaraland mole rats also showed reduced lateral and medial efferent terminal density. Developmentally, naked mole rats showed reduced and prolonged postnatal reorganization of afferent and efferent innervation. Damaraland mole rats showed no evidence of postnatal reorganization. Differences in cochlear innervation specifically between the two subterranean rodents and more broadly among rodents provides insight into the cochlear mechanisms that enhance frequency sensitivity and sound localization, maturation of the auditory system, and the evolutionary adaptations occurring in response to subterranean environments.
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Affiliation(s)
- Catherine M Barone
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Sytse Douma
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Daniël O J Reijntjes
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Brigitte M Browe
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Christine Köppl
- Cluster of Excellence "Hearing4All", Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Georg Klump
- Cluster of Excellence "Hearing4All", Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Thomas J Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Sonja J Pyott
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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Voltage-Gated Calcium Influx Modifies Cholinergic Inhibition of Inner Hair Cells in the Immature Rat Cochlea. J Neurosci 2018; 38:5677-5687. [PMID: 29789373 DOI: 10.1523/jneurosci.0230-18.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/14/2018] [Accepted: 05/16/2018] [Indexed: 11/21/2022] Open
Abstract
Until postnatal day (P) 12, inner hair cells of the rat cochlea are invested with both afferent and efferent synaptic connections. With the onset of hearing at P12, the efferent synapses disappear, and afferent (ribbon) synapses operate with greater efficiency. This change coincides with increased expression of voltage-gated potassium channels, the loss of calcium-dependent electrogenesis, and the onset of graded receptor potentials driven by sound. The transient efferent synapses include near-membrane postsynaptic cisterns thought to regulate calcium influx through the hair cell's α9-containing and α10-containing nicotinic acetylcholine receptors. This influx activates small-conductance Ca2+-activated K+ (SK) channels. Serial-section electron microscopy of inner hair cells from two 9-d-old (male) rat pups revealed many postsynaptic efferent cisterns and presynaptic afferent ribbons whose average minimal separation in five cells ranged from 1.1 to 1.7 μm. Efferent synaptic function was studied in rat pups (age, 7-9 d) of either sex. The duration of these SK channel-mediated IPSCs was increased by enhanced calcium influx through L-type voltage-gated channels, combined with ryanodine-sensitive release from internal stores-presumably the near-membrane postsynaptic cistern. These data support the possibility that inner hair cell calcium electrogenesis modulates the efficacy of efferent inhibition during the maturation of inner hair cell synapses.SIGNIFICANCE STATEMENT Strict calcium buffering is essential for cellular function. This problem is especially acute for compact hair cells where increasing cytoplasmic calcium promotes the opposing functions of closely adjoining afferent and efferent synapses. The near-membrane postsynaptic cistern at efferent synapses segregates synaptic calcium signals by acting as a dynamic calcium store. The hair cell serves as an informative model for synapses with postsynaptic cisterns (C synapses) found in central neurons.
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18
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Tang ZQ, Lu Y. Anatomy and Physiology of Metabotropic Glutamate Receptors in Mammalian and Avian Auditory System. ACTA ACUST UNITED AC 2018; 1. [PMID: 30854519 DOI: 10.24966/tap-7752/100001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Glutamate, as the major excitatory neurotransmitter used in the vertebrate brain, activates ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs), which mediate fast and slow neuronal actions, respectively. mGluRs play important modulatory roles in many brain areas, forming potential targets for drugs developed to treat brain disorders. Here, we review studies on mGluRs in the mammalian and avian auditory system. Although anatomical expression of mGluRs in the cochlear nucleus has been well characterized, data for other auditory nuclei await more systematic investigations especially at the electron microscopy level. The physiology of mGluRs has been extensively studied using in vitro brain slice preparations, with a focus on the auditory circuitry in the brainstem. These in vitro physiological studies have demonstrated that mGluRs participate in synaptic transmission, regulate ionic homeostasis, induce synaptic plasticity, and maintain the balance between Excitation and Inhibition (E/I) in a variety of auditory structures. However, the modulatory roles of mGluRs in auditory processing remain largely unclear at the system and behavioral levels, and the functions of mGluRs in auditory disorders remain entirely unknown.
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Affiliation(s)
- Zheng-Quan Tang
- Oregon Hearing Research Center, Vollum Institute, Oregon Health and Science University, Oregon, USA
| | - Yong Lu
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Ohio, USA
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19
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Compartmentalization of antagonistic Ca 2+ signals in developing cochlear hair cells. Proc Natl Acad Sci U S A 2018; 115:E2095-E2104. [PMID: 29439202 DOI: 10.1073/pnas.1719077115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During a critical developmental period, cochlear inner hair cells (IHCs) exhibit sensory-independent activity, featuring action potentials in which Ca2+ ions play a fundamental role in driving both spiking and glutamate release onto synapses with afferent auditory neurons. This spontaneous activity is controlled by a cholinergic input to the IHC, activating a specialized nicotinic receptor with high Ca2+ permeability, and coupled to the activation of hyperpolarizing SK channels. The mechanisms underlying distinct excitatory and inhibitory Ca2+ roles within a small, compact IHC are unknown. Making use of Ca2+ imaging, afferent auditory bouton recordings, and electron microscopy, the present work shows that unusually high intracellular Ca2+ buffering and "subsynaptic" cisterns provide efficient compartmentalization and tight control of cholinergic Ca2+ signals. Thus, synaptic efferent Ca2+ spillover and cross-talk are prevented, and the cholinergic input preserves its inhibitory signature to ensure normal development of the auditory system.
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20
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Steinert JR. Activated inhibition in regulating excitability. J Physiol 2017; 595:3243-3244. [PMID: 28295346 PMCID: PMC5451725 DOI: 10.1113/jp274196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Joern R Steinert
- MRC Toxicology Unit, Hodgkin Building, University of Leicester, Lancaster Road, Leicester, LE1 9HN, UK
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