1
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Sutton SS, Magagnoli J, Cummings TH, Hardin JW. Calcium Channel Blockers and the Risk of Sensorineural Hearing Loss. Otol Neurotol 2022; 43:e140-e147. [PMID: 34855682 DOI: 10.1097/mao.0000000000003419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate calcium channel blockers as a potential prophylactic agent for sensorineural hearing loss (SNHL).Patients: We used a retrospective cohort of US veterans treated by the Veteran's Affairs healthcare system. Patients were included in the study if 1) they were diagnosed with high blood pressure; 2) had no previous diagnosis of SNHL; 3) were prescribed a calcium channel blocker after diagnosis or as a control cohort, patients who had no antihypertensive medication use. INTERVENTION Patients were categorized into mutually exclusive cohorts by their antihypertensive medication exposure: calcium channel blocker exposed and no antihypertensive medication exposure. MAIN OUTCOME MEASURE Incident SNHL was defined as an inpatient or outpatient record with diagnosis codes international classification of diseases (ICD)-9-CM 389.1 or ICD-10-CM H90, H90.41, H90.42, H90.A21, H90.A22. An audiology or otolaryngology clinic visit was required for patients with an outpatient diagnosis of SNHL. RESULTS A total of 1,338,409 patients met the inclusion criteria consisting of 292,981 patients with CCBs (25,614 with verapamil and 267,367 with other CCBs) and 1,045,428 patients with no antihypertensive medication. On average, patients were middle-aged, White men with a body mass index (BMI) of 30+. Cox proportional hazards model estimates from propensity score matched data revealed CCB users had a 23.6% decreased risk of SNHL compared with those with no antihypertensive medication use (hazard ratios [HR] = 0.764; 95% confidence interval = [0.752-0.777]). CONCLUSION This analysis found evidence supporting the theory that calcium channel blockers might be a potential prophylactic agent for sensorineural hearing loss. Additional research is warranted.
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Affiliation(s)
- S Scott Sutton
- Dorn Research Institute, Columbia Department of Veterans Affairs Health Care System
- Department of Clinical Pharmacy and Outcomes Sciences, College of Pharmacy
| | - Joseph Magagnoli
- Dorn Research Institute, Columbia Department of Veterans Affairs Health Care System
- Department of Clinical Pharmacy and Outcomes Sciences, College of Pharmacy
| | - Tammy H Cummings
- Dorn Research Institute, Columbia Department of Veterans Affairs Health Care System
- Department of Clinical Pharmacy and Outcomes Sciences, College of Pharmacy
| | - James W Hardin
- Dorn Research Institute, Columbia Department of Veterans Affairs Health Care System
- Department of Epidemiology & Biostatistics, University of South Carolina, Columbia, South Carolina
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2
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Webb SD, Orton LD. Microglial peri-somatic abutments classify two novel types of GABAergic neuron in the inferior colliculus. Eur J Neurosci 2020; 54:5815-5833. [PMID: 33278847 DOI: 10.1111/ejn.15075] [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] [Received: 06/16/2019] [Revised: 05/14/2020] [Accepted: 05/20/2020] [Indexed: 12/22/2022]
Abstract
Emerging evidence suggests functional roles for microglia in the healthy, mature nervous system. However, we know little of the cellular density and ramified morphology of microglia in sensory systems, and even less of their inter-relationship with inhibitory neurons. We therefore conducted fluorescent multi-channel immunohistochemistry and confocal microscopy in guinea pigs of both sexes for Iba1, GAD67, GFAP, calbindin, and calretinin. We explored these markers in the inferior colliculi (IC), which contain sub-regions specialized for different aspects of auditory processing. First, we found that while the density of Iba1+ somata is similar throughout the IC parenchyma, Iba1+ microglia in dorsal cortex are significantly more ramified than those in the central nucleus or lateral cortex. Conversely, Iba1+ ramifications in ventral central nucleus, a region with the highest density of GAD67+ (putative GABAergic) neurons in IC, are longer with fewer ramifications. Second, we observed extensive abutments of ramified Iba1+ processes onto GAD67+ somata throughout the whole IC and developed novel measures to quantify these. Cluster analyses revealed two novel sub-types of GAD67+ neuron that differ in the quantity of Iba1+ somatic abutments they receive. Unlike previous classification schemes for GAD67+ neurons in IC, these clusters are not related to GAD67+ soma size. Taken together, these data demonstrate that microglial ramifications vary between IC sub-regions in the healthy, adult IC, possibly related to the ongoing demands of their niche. Furthermore, Iba1+ abutments onto neuronal somata are a novel means by which GAD67+ neurons can be classified.
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Affiliation(s)
- Samuel David Webb
- Department of Life Sciences, Manchester Metropolitan University, Manchester, UK
| | - Llwyd David Orton
- Department of Life Sciences, Manchester Metropolitan University, Manchester, UK.,Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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3
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Belekhova MG, Kenigfest NB, Chmykhova NM. Evolutionary Formation and Functional
Significance
of the Core–Belt Pattern of Neural Organization of Rostral Auditory
Centers in Vertebrates. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s0022093020040018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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4
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Lee JK, Kim MJ. The distribution of calbindin-D28k, parvalbumin, and calretinin immunoreactivity in the inferior colliculus of circling mouse. Anat Cell Biol 2017; 50:230-238. [PMID: 29043102 PMCID: PMC5639178 DOI: 10.5115/acb.2017.50.3.230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 11/27/2022] Open
Abstract
The circling mice with tmie gene mutation are known as an animal deafness model, which showed hyperactive circling movement. Recently, the reinvestigation of circling mouse was performed to check the inner ear pathology as a main lesion of early hearing loss. In this trial, the inner ear organs were not so damaged to cause the hearing deficit of circling (cir/cir) mouse at 18 postnatal day (P18) though auditory brainstem response data indicated hearing loss of cir/cir mice at P18. Thus, another mechanism may be correlated with the early hearing loss of cir/cir mice at P18. Hearing loss in the early life can disrupt the ascending and descending information to inferior colliculus (IC) as integration site. There were many reports that hearing loss could result in the changes in Ca2+ concentration by either cochlear ablation or genetic defect. However, little was known to be reported about the correlation between the pathology of IC and Ca2+ changes in circling mice. Therefore, the present study investigated the distribution of calcium-binding proteins (CaBPs), calbindin-D28k, parvalbumin, and calretinin immunoreactivity (IR) in the IC to compare among wild-type (+/+), heterozygous (+/cir), and homozygous (cir/cir) mice by immunohistochemistry. The decreases of CaBPs IR in cir/cir were statistically significant in the neurons as well as neuropil of IC. Thus, this study proposed overall distributional alteration of CaBPs IR in the IC caused by early hearing defect and might be helpful to elucidate the pathology of central auditory disorder related with Ca2+ metabolism.
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Affiliation(s)
- Jin-Koo Lee
- Department of Pharmacology, Dankook University College of Medicine, Cheonan, Korea
| | - Myeung Ju Kim
- Department of Anatomy, Dankook University College of Medicine, Cheonan, Korea
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5
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Rozycka A, Liguz-Lecznar M. The space where aging acts: focus on the GABAergic synapse. Aging Cell 2017; 16:634-643. [PMID: 28497576 PMCID: PMC5506442 DOI: 10.1111/acel.12605] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2017] [Indexed: 12/19/2022] Open
Abstract
As it was established that aging is not associated with massive neuronal loss, as was believed in the mid‐20th Century, scientific interest has addressed the influence of aging on particular neuronal subpopulations and their synaptic contacts, which constitute the substrate for neural plasticity. Inhibitory neurons represent the most complex and diverse group of neurons, showing distinct molecular and physiological characteristics and possessing a compelling ability to control the physiology of neural circuits. This review focuses on the aging of GABAergic neurons and synapses. Understanding how aging affects synapses of particular neuronal subpopulations may help explain the heterogeneity of aging‐related effects. We reviewed the literature concerning the effects of aging on the numbers of GABAergic neurons and synapses as well as aging‐related alterations in their presynaptic and postsynaptic components. Finally, we discussed the influence of those changes on the plasticity of the GABAergic system, highlighting our results concerning aging in mouse somatosensory cortex and linking them to plasticity impairments and brain disorders. We posit that aging‐induced impairments of the GABAergic system lead to an inhibitory/excitatory imbalance, thereby decreasing neuron's ability to respond with plastic changes to environmental and cellular challenges, leaving the brain more vulnerable to cognitive decline and damage by synaptopathic diseases.
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Affiliation(s)
- Aleksandra Rozycka
- Department of Molecular and Cellular Neurobiology; Nencki Institute of Experimental Biology; Polish Academy of Sciences; 3 Pasteur Street Warsaw 02-093 Poland
| | - Monika Liguz-Lecznar
- Department of Molecular and Cellular Neurobiology; Nencki Institute of Experimental Biology; Polish Academy of Sciences; 3 Pasteur Street Warsaw 02-093 Poland
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6
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Sivaramakrishnan S, Lynch WP. Rebound from Inhibition: Self-Correction against Neurodegeneration? JOURNAL OF CLINICAL & CELLULAR IMMUNOLOGY 2017; 8:492. [PMID: 28775912 PMCID: PMC5538264 DOI: 10.4172/2155-9899.1000492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neural networks play a critical role in establishing constraints on excitability in the central nervous system. Several recent studies have suggested that network dysfunction in the brain and spinal cord are compromised following insult by a neurodegenerative trigger and might precede eventual neuronal loss and neurological impairment. Early intervention of network excitability and plasticity might therefore be critical in resetting hyperexcitability and preventing later neuronal damage. Here, the behavior of neurons that generate burst firing upon recovery from inhibitory input or intrinsic membrane hyperpolarization (rebound neurons) is examined in the context of neural networks that underlie rhythmic activity observed in areas of the brain and spinal cord that are vulnerable to neurodegeneration. In a non-inflammatory rodent model of spongiform neurodegenerative disease triggered by retrovirus infection of glia, rebound neurons are particularly vulnerable to neurodegeneration, likely due to an inherently low calcium buffering capacity. The dysfunction of rebound neurons translates into a dysfunction of rhythmic neural circuits, compromising normal neurological function and leading to eventual morbidity. Understanding how virus infection of glia can mediate dysfunction of rebound neurons, induce hyperexcitability and loss of rhythmic function, pathologic features observed in neurodegenerative disorders ranging from epilepsy to motor neuron disease, might therefore suggest a common pathway for early therapeutic intervention.
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Affiliation(s)
- Shobhana Sivaramakrishnan
- Department of Otolaryngology, Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - William P. Lynch
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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7
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Stebbings KA, Choi HW, Ravindra A, Caspary DM, Turner JG, Llano DA. Ageing-related changes in GABAergic inhibition in mouse auditory cortex, measured using in vitro flavoprotein autofluorescence imaging. J Physiol 2015; 594:207-21. [PMID: 26503482 DOI: 10.1113/jp271221] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 10/18/2015] [Indexed: 12/24/2022] Open
Abstract
KEY POINTS Ageing is associated with hearing loss and changes in GABAergic signalling in the auditory system. We tested whether GABAergic signalling in an isolated forebrain preparation also showed ageing-related changes. A novel approach was used, whereby population imaging was coupled to quantitative pharmacological sensitivity. Sensitivity to GABAA blockade was inversely associated with age and cortical thickness, but hearing loss did not independently contribute to the change in GABAA ergic sensitivity. Redox states in the auditory cortex of young and aged animals were similar, suggesting that the differences in GABAA ergic sensitivity are unlikely to be due to differences in slice health. To examine ageing-related changes in the earliest stages of auditory cortical processing, population auditory cortical responses to thalamic afferent stimulation were studied in brain slices obtained from young and aged CBA/CAj mice (up to 28 months of age). Cortical responses were measured using flavoprotein autofluorescence imaging, and ageing-related changes in inhibition were assessed by measuring the sensitivity of these responses to blockade of GABAA receptors using bath-applied SR95531. The maximum auditory cortical response to afferent stimulation was not different between young and aged animals under control conditions, but responses to afferent stimulation in aged animals showed a significantly lower sensitivity to GABA blockade with SR95531. Cortical thickness, but not hearing loss, improved the prediction of all imaging variables when combined with age, particularly sensitivity to GABA blockade for the maximum response. To determine if the observed differences between slices from young and aged animals were due to differences in slice health, the redox state in the auditory cortex was assessed by measuring the FAD+/NADH ratio using fluorescence imaging. We found that this ratio is highly sensitive to known redox stressors such as H2 O2 and NaCN; however, no difference was found between young and aged animals. By using a new approach to quantitatively assess pharmacological sensitivity of population-level cortical responses to afferent stimulation, these data demonstrate that auditory cortical inhibition diminishes with ageing. Furthermore, these data establish a significant relationship between cortical thickness and GABAergic sensitivity, which had not previously been observed in an animal model of ageing.
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Affiliation(s)
- K A Stebbings
- Neuroscience Program, University of Illinois at Urbana-Champaign, IL, USA
| | - H W Choi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, IL, USA
| | - A Ravindra
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, IL, USA
| | - D M Caspary
- Department of Pharmacology, Southern Illinois University College of Medicine, IL, USA
| | - J G Turner
- Department of Pharmacology, Southern Illinois University College of Medicine, IL, USA.,Department of Psychology, Illinois College, IL, USA
| | - D A Llano
- Neuroscience Program, University of Illinois at Urbana-Champaign, IL, USA.,Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, IL, USA
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8
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Campos LMG, Osório EC, Santos GLDS, Nogueira MI, Cruz-Rizzolo RJ, Pinato L. Temporal changes in calcium-binding proteins in the medial geniculate nucleus of the monkey Sapajus apella. J Chem Neuroanat 2015. [PMID: 26222835 DOI: 10.1016/j.jchemneu.2015.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The subdivisions of the medial geniculate complex can be distinguished based on the immunostaining of calcium-binding proteins and by the properties of the neurons within each subdivision. The possibility of changes in neurochemistry in this and other central auditory areas are important aspects to understand the basis that contributing to functional variations determined by environmental cycles or the animal's cycles of activity and rest. This study investigated, for the first time, day/night differences in the amounts of parvalbumin-, calretinin- and calbindin-containing neurons in the thalamic auditory center of a non-human primate, Sapajus apella. The immunoreactivity of the PV-IR, CB-IR and CR-IR neurons demonstrated different distribution patterns among the subdivisions of the medial geniculate. Moreover, a high number of CB- and CR-IR neurons were found during day, whereas PV-IR was predominant at night. We conclude that in addition to the chemical heterogeneity of the medial geniculate nucleus with respect to the expression of calcium-binding proteins, expression also varied relative to periods of light and darkness, which may be important for a possible functional adaptation of central auditory areas to environmental changes and thus ensure the survival and development of several related functions.
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Affiliation(s)
- Leila M G Campos
- Department of Speech-Language and Hearing Therapy, São Paulo State University, Marilia, SP, Brazil; University of Marilia, Medical School, Marilia, SP, Brazil
| | - Elaine C Osório
- Department of Speech-Language and Hearing Therapy, São Paulo State University, Marilia, SP, Brazil
| | | | - Maria Inês Nogueira
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, SP, Brazil
| | | | - Luciana Pinato
- Department of Speech-Language and Hearing Therapy, São Paulo State University, Marilia, SP, Brazil.
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9
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Burianová J, Ouda L, Syka J. The influence of aging on the number of neurons and levels of non-phosporylated neurofilament proteins in the central auditory system of rats. Front Aging Neurosci 2015; 7:27. [PMID: 25852543 PMCID: PMC4366680 DOI: 10.3389/fnagi.2015.00027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 02/23/2015] [Indexed: 12/11/2022] Open
Abstract
In the present study, an unbiased stereological method was used to determine the number of all neurons in Nissl stained sections of the inferior colliculus (IC), medial geniculate body (MGB), and auditory cortex (AC) in rats (strains Long Evans and Fischer 344) and their changes with aging. In addition, using the optical fractionator and western blot technique, we also evaluated the number of SMI-32-immunoreactive (-ir) neurons and levels of non-phosphorylated neurofilament proteins in the IC, MGB, AC, and visual cortex of young and old rats of the two strains. The SMI-32 positive neuronal population comprises about 10% of all neurons in the rat IC, MGB, and AC and represents a prevalent population of large neurons with highly myelinated and projecting processes. In both Long Evans and Fischer 344 rats, the total number of neurons in the IC was roughly similar to that in the AC. With aging, we found a rather mild and statistically non-significant decline in the total number of neurons in all three analyzed auditory regions in both rat strains. In contrast to this, the absolute number of SMI-32-ir neurons in both Long Evans and Fischer 344 rats significantly decreased with aging in all the examined structures. The western blot technique also revealed a significant age-related decline in the levels of non-phosphorylated neurofilaments in the auditory brain structures, 30–35%. Our results demonstrate that presbycusis in rats is not likely to be primarily associated with changes in the total number of neurons. On the other hand, the pronounced age-related decline in the number of neurons containing non-phosphorylated neurofilaments as well as their protein levels in the central auditory system may contribute to age-related deterioration of hearing function.
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Affiliation(s)
- Jana Burianová
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague Czech Republic
| | - Ladislav Ouda
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague Czech Republic
| | - Josef Syka
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague Czech Republic
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10
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Age-related changes in the central auditory system. Cell Tissue Res 2015; 361:337-58. [DOI: 10.1007/s00441-014-2107-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/22/2014] [Indexed: 12/19/2022]
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11
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Gray DT, Engle JR, Rudolph ML, Recanzone GH. Regional and age-related differences in GAD67 expression of parvalbumin- and calbindin-expressing neurons in the rhesus macaque auditory midbrain and brainstem. J Comp Neurol 2014; 522:4074-84. [PMID: 25091320 PMCID: PMC4263274 DOI: 10.1002/cne.23659] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 07/31/2014] [Accepted: 08/01/2014] [Indexed: 11/08/2022]
Abstract
Neurons expressing the calcium binding proteins (CaBPs) parvalbumin (PV) and calbindin (CB) have shown age-related density changes throughout the ascending auditory system of both rodents and macaque monkeys. In the cerebral cortex, neurons expressing these CaBPs express markers of γ-aminobutyric acidergic neurotransmission, such as GAD67, and have well-understood physiological response properties. Recent evidence suggests that, in the rodent auditory brainstem, CaBP-containing cells do not express GAD67. It is unknown whether PV- and CB-containing cells in subcortical auditory structures of macaques similarly do not express GAD67, and a better understanding of the neurotransmission of neurons expressing these proteins is necessary for understanding the age-related changes in their density throughout the macaque auditory system. This was investigated with immunofluorescent double-labeling techniques to coregister PV- and CB-expressing neurons with GAD67 in the superior olivary complex and the inferior colliculus of young and aged rhesus macaques. The proportions of GAD67-expressing PV- and CB-positive neurons were computed with unbiased sampling techniques. Our results indicate that between 42% and 62% of PV- and CB-positive neurons in the auditory brainstem and midbrain express GAD67, which is significantly less than in the cerebrum. In general, fewer PV(+) neurons and more CB(+) neurons expressed GAD67 as a function of age. These results demonstrate that the inhibitory molecular profile of PV- and CB-expressing neurons can change with age in subcortical auditory structures and that these neurons are distinct from the well-described inhibitory interneurons that express these proteins in the cerebral cortex.
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Affiliation(s)
- D T Gray
- Center for Neuroscience, University of California at Davis, Davis, California, 95616; Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, Arizona, 85721
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12
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Gray DT, Engle JR, Recanzone GH. Age-related neurochemical changes in the rhesus macaque cochlear nucleus. J Comp Neurol 2014; 522:1527-41. [PMID: 24127432 DOI: 10.1002/cne.23479] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/28/2013] [Accepted: 09/25/2013] [Indexed: 11/07/2022]
Abstract
Neurochemical changes in the expression of various proteins within the central auditory system have been associated with natural aging. These changes may compensate in part for the loss of auditory sensitivity arising from two phenomena of the aging auditory system: cochlear histopathologies and increased excitability of central auditory neurons. Recent studies in the macaque monkey have revealed age-related changes in the density of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase (NADPHd) and parvalbumin (PV)-positive cells within the inferior colliculus and superior olivary complex. The cochlear nucleus (CN), which is the first central auditory nucleus, remains unstudied. Since the CN participates in the generation of the auditory brainstem response (ABR) and receives direct innervation from the cochlea, it serves as an ideal nucleus to compare the relationship between these neurochemical changes and the physiological and peripheral changes of the aging auditory system. We used stereological sampling to calculate the densities of NADPHd and PV reactive neurons within the three subdivisions of the CN in middle-aged and aged rhesus macaques. Regression analyses of these values with ABR properties and cochlear histopathologies revealed relationships between these cell types and the changing characteristics of the aging auditory system. Our results indicate that NADPHd expression does change with age in a specific subdivision of the CN, but PV does not. Conversely, PV expression correlated with ABR amplitudes and outer hair cell loss in the cochlea, but NADPHd did not. These results indicate that NADPHd and PV may take part in distinct compensatory efforts of the aging auditory system.
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Affiliation(s)
- Daniel T Gray
- Center for Neuroscience, University of California at Davis, Davis, CA, 95616
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13
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Gröschel M, Hubert N, Müller S, Ernst A, Basta D. Age-dependent changes of calcium related activity in the central auditory pathway. Exp Gerontol 2014; 58:235-43. [DOI: 10.1016/j.exger.2014.08.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 07/31/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
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14
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Li Y, Davey RA, Sivaramakrishnan S, Lynch WP. Postinhibitory rebound neurons and networks are disrupted in retrovirus-induced spongiform neurodegeneration. J Neurophysiol 2014; 112:683-704. [PMID: 25252336 DOI: 10.1152/jn.00227.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Certain retroviruses induce progressive spongiform motor neuron disease with features resembling prion diseases and amyotrophic lateral sclerosis. With the neurovirulent murine leukemia virus (MLV) FrCasE, Env protein expression within glia leads to postsynaptic vacuolation, cellular effacement, and neuronal loss in the absence of neuroinflammation. To understand the physiological changes associated with MLV-induced spongiosis, and its neuronal specificity, we employed patch-clamp recordings and voltage-sensitive dye imaging in brain slices of the mouse inferior colliculus (IC), a midbrain nucleus that undergoes extensive spongiosis. IC neurons characterized by postinhibitory rebound firing (PIR) were selectively affected in FrCasE-infected mice. Coincident with Env expression in microglia and in glia characterized by NG2 proteoglycan expression (NG2 cells), rebound neurons (RNs) lost PIR, became hyperexcitable, and were reduced in number. PIR loss and hyperexcitability were reversed by raising internal calcium buffer concentrations in RNs. PIR-initiated rhythmic circuits were disrupted, and spontaneous synchronized bursting and prolonged depolarizations were widespread. Other IC neuron cell types and circuits within the same degenerative environment were unaffected. Antagonists of NMDA and/or AMPA receptors reduced burst firing in the IC but did not affect prolonged depolarizations. Antagonists of L-type calcium channels abolished both bursts and slow depolarizations. IC infection by the nonneurovirulent isogenic virus Friend 57E (Fr57E), whose Env protein is structurally similar to FrCasE, showed no RN hyperactivity or cell loss; however, PIR latency increased. These findings suggest that spongiform neurodegeneration arises from the unique excitability of RNs, their local regulation by glia, and the disruption of this relationship by glial expression of abnormal protein.
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Affiliation(s)
- Ying Li
- Department of Integrated Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
| | - Robert A Davey
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas; and
| | | | - William P Lynch
- Department of Integrated Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
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15
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Engle JR, Gray DT, Turner H, Udell JB, Recanzone GH. Age-related neurochemical changes in the rhesus macaque inferior colliculus. Front Aging Neurosci 2014; 6:73. [PMID: 24795627 PMCID: PMC4001037 DOI: 10.3389/fnagi.2014.00073] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 03/31/2014] [Indexed: 01/19/2023] Open
Abstract
Age-related hearing loss (ARHL) is marked by audiometric hearing deficits that propagate along the auditory pathway. Neurochemical changes as a function of aging have also been identified in neurons along the auditory pathway in both rodents and carnivores, however, very little is known about how these neurochemicals change in the non-human primate. To examine how these compensatory neurochemical changes relate to normal aging and audiometric sensitivity along the auditory pathway, we collected auditory brainstem responses (ABRs) and brain specimens from seven rhesus monkeys spanning in age from 15 to 35 years old, and examined the relationship between click evoked ABR thresholds and the ABR evoked pure tone average (PTA) and changes in the number of parvalbumin and NADPH-diaphorase positive cells in the auditory midbrain. We found that the number of parvalbumin positive cells in the central nucleus and the surrounding cortex regions of the inferior colliculus were strongly correlated with advancing age and ABR PTA. We also found that the numbers of NADPHd positive cells in these same regions were not associated with normal aging or changes in the ABR thresholds. These findings suggest that the auditory midbrain undergoes an up-regulation of parvalbumin expressing neurons with aging that is related to changes in the processing of frequencies across the audiometric range.
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Affiliation(s)
- James R Engle
- Evelyn F. McKnight Brain Institute, University of Arizona at Tucson Tucson, AZ, USA ; Center for Neuroscience, University of California at Davis Davis, CA, USA ; Department of Psychology, University of California at Davis Davis, CA, USA
| | - Daniel T Gray
- Center for Neuroscience, University of California at Davis Davis, CA, USA
| | - Heather Turner
- Center for Neuroscience, University of California at Davis Davis, CA, USA
| | - Julia B Udell
- Center for Neuroscience, University of California at Davis Davis, CA, USA
| | - Gregg H Recanzone
- Center for Neuroscience, University of California at Davis Davis, CA, USA ; Department of Psychology, University of California at Davis Davis, CA, USA ; Department of Neurobiology, Physiology and Behavior, University of California at Davis Davis, CA USA
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16
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Gray DT, Engle JR, Recanzone GH. Age-related neurochemical changes in the rhesus macaque superior olivary complex. J Comp Neurol 2013; 522:573-91. [PMID: 25232570 DOI: 10.1002/cne.23427] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Positive immunoreactivity to the calcium-binding protein parvalbumin (PV) and nitric oxide synthase NADPH diaphorase (NADPHd) is well documented within neurons of the central auditory system of both rodents and primates. These proteins are thought to play roles in the regulation of auditory processing. Studies examining the age-related changes in expression of these proteins have been conducted primarily in rodents but are sparse in primate models. In the brainstem, the superior olivary complex (SOC) is crucial for the computation of sound source localization in azimuth, and one hallmark of age-related hearing deficits is a reduced ability to localize sounds. To investigate how these histochemical markers change as a function of age and hearing loss, we studied eight rhesus macaques ranging in age from 12 to 35 years. Auditory brainstem responses (ABRs) were obtained in anesthetized animals for click and tone stimuli. The brainstems of the sesame animals were then stained for PV and NADPHd reactivity. Reactive neurons in the three nuclei of the SOC were counted, and the densities of each cell type were calculated. We found that PV and NADPHd expression increased with both age and ABR thresholds in the medial superior olive but not in either the medial nucleus of the trapezoid body or the lateral superior olive. Together these results suggest that the changes in protein expression employed by the SOC may compensate for the loss of efficacy of auditory sensitivity in the aged primate.
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Affiliation(s)
- Daniel T Gray
- Center for Neuroscience, University of California at Davis, Davis, California 95616
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17
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Gray DT, Rudolph ML, Engle JR, Recanzone GH. Parvalbumin increases in the medial and lateral geniculate nuclei of aged rhesus macaques. Front Aging Neurosci 2013; 5:69. [PMID: 24265617 PMCID: PMC3821177 DOI: 10.3389/fnagi.2013.00069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/16/2013] [Indexed: 12/20/2022] Open
Abstract
Subcortical auditory structures in the macaque auditory system increase their densities of neurons expressing the calcium binding protein parvalbumin (PV) with age. However, it is unknown whether these increases occur in the thalamic division of the auditory system, the medial geniculate nucleus (MGN). Furthermore, it is also unclear whether these age-related changes are specific to the macaque auditory system or are generalized to other sensory systems. To address these questions, the PV immunoreactivity of the medial and lateral geniculate nuclei (LGN) from seven rhesus macaques ranging in age from 15 to 35 was assessed. Densities of PV expressing neurons in the three subdivisions of the MGN and the six layers of the LGN were calculated separately using unbiased stereological sampling techniques. We found that the ventral and magnocellular subdivisions of the MGN and all six layers of the LGN increased their expressions of PV with age, although increases in the MGN were greater in magnitude than in the LGN. Together, these results suggest that the MGN shows age-related increases in PV expression as is seen throughout the macaque ascending auditory system, and that the analogous region of the visual system shows smaller increases. We conclude that, while there are some similarities between sensory systems, the age-related neurochemical changes seen throughout the macaque auditory system cannot be fully generalized to other sensory systems.
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Affiliation(s)
- Daniel T. Gray
- Center for Neuroscience, University of California at DavisDavis, CA, USA
| | - Megan L. Rudolph
- Center for Neuroscience, University of California at DavisDavis, CA, USA
| | - James R. Engle
- Evelyn F. McKnight Brain Institute, University of ArizonaTucson, AZ, USA
| | - Gregg H. Recanzone
- Center for Neuroscience, University of California at DavisDavis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California at DavisDavis, CA, USA
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18
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Sarnat HB. Clinical neuropathology practice guide 5-2013: markers of neuronal maturation. Clin Neuropathol 2013; 32:340-69. [PMID: 23883617 PMCID: PMC3796735 DOI: 10.5414/np300638] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/23/2013] [Indexed: 11/18/2022] Open
Abstract
This review surveys immunocytochemical and histochemical markers of neuronal lineage for application to tissue sections of fetal and neonatal brain. They determine maturation of individual nerve cells as the tissue progresses to mature architecture. From a developmental perspective, neuronal markers are all about timing. These diverse cellular labels may be classified in two ways: 1) time of onset of expression (early; intermediate; late); 2) labeling of subcellular structures or metabolic functions (nucleoproteins; synaptic vesicle proteins; enolases; cytoskeletal elements; calcium-binding; nucleic acids; mitochondria). Apart from these positive markers of maturation, other negative markers are expressed in primitive neuroepithelial cells and early stages of neuroblast maturation, but no longer are demonstrated after initial stages of maturation. These examinations are relevant for studies of normal neuroembryology at the cellular level. In fetal and perinatal neuropathology they provide control criteria for application to malformations of the brain, inborn metabolic disorders and acquired fetal insults in which neuroblastic maturation may be altered. Disorders, in which cells differentiate abnormally, as in tuberous sclerosis and hemimegalencephaly, pose another yet aspect of mixed cellular lineage. The measurement in living patients, especially neonates, of serum and CSF levels of enolases, chromogranins and S-100 proteins as biomarkers of brain damage may potentially be correlated with their corresponding tissue markers at autopsy in infants who do not survive. The neuropathological markers here described can be performed in ordinary hospital laboratories, not just research facilities, and offer another dimension of diagnostic precision in interpreting abnormally developed fetal and postnatal brains.
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Metabolic changes in the auditory cortex in presbycusis demonstrated by MR spectroscopy. Exp Gerontol 2013; 48:795-800. [PMID: 23648586 DOI: 10.1016/j.exger.2013.04.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/04/2013] [Accepted: 04/25/2013] [Indexed: 11/20/2022]
Abstract
In humans, aging is accompanied by the deterioration of the hearing function--presbycusis. The major etiology for presbycusis is the loss of hair cells in the inner ear; less well known are changes in the central auditory system. Therefore, we used 1H magnetic resonance spectroscopy at 3T tomograph to examine metabolite levels in the auditory cortex of three groups of subjects: young healthy subjects less than 30 years old and subjects older than 65 years either with mild presbycusis corresponding to their age or with expressed presbycusis. Hearing function in all subjects was examined by pure tone audiometry (125-16,000 Hz). Significant differences were found in the concentrations of glutamate and N-acetylaspartate, with lower levels in aged subjects. Lactate was particularly increased in subjects with expressed presbycusis. Significant differences were not found in other metabolites, including GABA, between young and elderly subjects. The results demonstrate that the age-related changes of the inner ear are accompanied by a decrease in the excitatory neurotransmitter glutamate as well as a lactate increase in the auditory cortex that is more expressed in elderly subjects with large hearing threshold shifts.
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Morona R, González A. Pattern of calbindin-D28k and calretinin immunoreactivity in the brain of Xenopus laevis during embryonic and larval development. J Comp Neurol 2013; 521:79-108. [PMID: 22678695 DOI: 10.1002/cne.23163] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/07/2012] [Accepted: 06/01/2012] [Indexed: 11/09/2022]
Abstract
The present study represents a detailed spatiotemporal analysis of the localization of calbindin-D28k (CB) and calretinin (CR) immunoreactive structures in the brain of Xenopus laevis throughout development, conducted with the aim to correlate the onset of the immunoreactivity with the development of compartmentalization of distinct subdivisions recently identified in the brain of adult amphibians and primarily highlighted when analyzed within a segmental paradigm. CR and CB are expressed early in the brain and showed a progressively increasing expression throughout development, although transient expression in some neuronal subpopulations was also noted. Common and distinct characteristics in Xenopus, as compared with reported features during development in the brain of mammals, were observed. The development of specific regions in the forebrain such as the olfactory bulbs, the components of the basal ganglia and the amygdaloid complex, the alar and basal hypothalamic regions, and the distinct diencephalic neuromeres could be analyzed on the basis of the distinct expression of CB and CR in subregions. Similarly, the compartments of the mesencephalon and the main rhombencephalic regions, including the cerebellum, were differently highlighted by their specific content in CB and CR throughout development. Our results show the usefulness of the analysis of the distribution of these proteins as a tool in neuroanatomy to interpret developmental aspects of many brain regions.
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Affiliation(s)
- Ruth Morona
- Department of Cell Biology, University Complutense, 28040 Madrid, Spain
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21
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Ouda L, Syka J. Immunocytochemical profiles of inferior colliculus neurons in the rat and their changes with aging. Front Neural Circuits 2012; 6:68. [PMID: 23049499 PMCID: PMC3448074 DOI: 10.3389/fncir.2012.00068] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/04/2012] [Indexed: 12/04/2022] Open
Abstract
The inferior colliculus (IC) plays a strategic role in the central auditory system in relaying and processing acoustical information, and therefore its age-related changes may significantly influence the quality of the auditory function. A very complex processing of acoustical stimuli occurs in the IC, as supported also by the fact that the rat IC contains more neurons than all other subcortical auditory structures combined. GABAergic neurons, which predominantly co-express parvalbumin (PV), are present in the central nucleus of the IC in large numbers and to a lesser extent in the dorsal and external/lateral cortices of the IC. On the other hand, calbindin (CB) and calretinin (CR) are prevalent in the dorsal and external cortices of the IC, with only a few positive neurons in the central nucleus. The relationship between CB and CR expression in the IC and any neurotransmitter system has not yet been well established, but the distribution and morphology of the immunoreactive neurons suggest that they are at least partially non-GABAergic cells. The expression of glutamate decarboxylase (GAD) (a key enzyme for GABA synthesis) and calcium binding proteins (CBPs) in the IC of rats undergoes pronounced changes with aging that involve mostly a decline in protein expression and a decline in the number of immunoreactive neurons. Similar age-related changes in GAD, CB, and CR expression are present in the IC of two rat strains with differently preserved inner ear function up to late senescence (Long-Evans and Fischer 344), which suggests that these changes do not depend exclusively on peripheral deafferentation but are, at least partially, of central origin. These changes may be associated with the age-related deterioration in the processing of the temporal parameters of acoustical stimuli, which is not correlated with hearing threshold shifts, and therefore may contribute to central presbycusis.
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Affiliation(s)
- Ladislav Ouda
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic Prague, Czech Republic
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22
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Age-related changes in calbindin and calretinin immunoreactivity in the central auditory system of the rat. Exp Gerontol 2012; 47:497-506. [DOI: 10.1016/j.exger.2012.04.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/22/2012] [Accepted: 04/10/2012] [Indexed: 11/22/2022]
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23
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Tremblay MÈ, Zettel ML, Ison JR, Allen PD, Majewska AK. Effects of aging and sensory loss on glial cells in mouse visual and auditory cortices. Glia 2012; 60:541-58. [PMID: 22223464 DOI: 10.1002/glia.22287] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 12/05/2011] [Indexed: 12/11/2022]
Abstract
Normal aging is often accompanied by a progressive loss of receptor sensitivity in hearing and vision, whose consequences on cellular function in cortical sensory areas have remained largely unknown. By examining the primary auditory (A1) and visual (V1) cortices in two inbred strains of mice undergoing either age-related loss of audition (C57BL/6J) or vision (CBA/CaJ), we were able to describe cellular and subcellular changes that were associated with normal aging (occurring in A1 and V1 of both strains) or specifically with age-related sensory loss (only in A1 of C57BL/6J or V1 of CBA/CaJ), using immunocytochemical electron microscopy and light microscopy. While the changes were subtle in neurons, glial cells and especially microglia were transformed in aged animals. Microglia became more numerous and irregularly distributed, displayed more variable cell body and process morphologies, occupied smaller territories, and accumulated phagocytic inclusions that often displayed ultrastructural features of synaptic elements. Additionally, evidence of myelination defects were observed, and aged oligodendrocytes became more numerous and were more often encountered in contiguous pairs. Most of these effects were profoundly exacerbated by age-related sensory loss. Together, our results suggest that the age-related alteration of glial cells in sensory cortical areas can be accelerated by activity-driven central mechanisms that result from an age-related loss of peripheral sensitivity. In light of our observations, these age-related changes in sensory function should be considered when investigating cellular, cortical, and behavioral functions throughout the lifespan in these commonly used C57BL/6J and CBA/CaJ mouse models.
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Affiliation(s)
- Marie-Ève Tremblay
- Department of Neurobiology and Anatomy and Center for Visual Science, University of Rochester, Rochester, New York 14642, USA
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24
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Lei D, Gao X, Perez P, Ohlemiller KK, Chen CC, Campbell KP, Hood AY, Bao J. Anti-epileptic drugs delay age-related loss of spiral ganglion neurons via T-type calcium channel. Hear Res 2011; 278:106-12. [PMID: 21640179 PMCID: PMC3152691 DOI: 10.1016/j.heares.2011.05.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 04/29/2011] [Accepted: 05/11/2011] [Indexed: 12/26/2022]
Abstract
Loss of spiral ganglion neurons is a major cause of age-related hearing loss (presbycusis). Despite being the third most prevalent condition afflicting elderly persons, there are no known medications to prevent presbycusis. Because calcium signaling has long been implicated in age-related neuronal death, we investigated T-type calcium channels. This family is comprised of three members (Ca(v)3.1, Ca(v)3.2, and Ca(v)3.3), based on their respective main pore-forming alpha subunits: α1G, α1H, and α1I. In the present study, we report a significant delay of age-related loss of cochlear function and preservation of spiral ganglion neurons in α1H null and heterozygous mice, clearly demonstrating an important role for Ca(v)3.2 in age-related neuronal loss. Furthermore, we show that anticonvulsant drugs from a family of T-type calcium channel blockers can significantly preserve spiral ganglion neurons during aging. To our knowledge, this is the first report of drugs capable of diminishing age-related loss of spiral ganglion neurons.
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MESH Headings
- Aging/drug effects
- Aging/metabolism
- Aging/pathology
- Animals
- Anticonvulsants/pharmacology
- Base Sequence
- Calcium Channel Blockers/pharmacology
- Calcium Channels, T-Type/deficiency
- Calcium Channels, T-Type/genetics
- Calcium Channels, T-Type/metabolism
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/pathology
- Mice
- Mice, Congenic
- Mice, Knockout
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Presbycusis/metabolism
- Presbycusis/pathology
- Presbycusis/prevention & control
- RNA/genetics
- RNA/metabolism
- Spiral Ganglion/drug effects
- Spiral Ganglion/innervation
- Spiral Ganglion/metabolism
- Spiral Ganglion/pathology
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Affiliation(s)
- Debin Lei
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Xia Gao
- Department of Otolaryngology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China 210008
| | - Philip Perez
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Kevin K Ohlemiller
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Chien-Chang Chen
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, 60153, USA
| | - Kevin P. Campbell
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, 60153, USA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, 60153, USA
- Department of Neurology, University of Iowa, Iowa City, Iowa, 60153, USA
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, 60153, USA
| | - Aizhen Yang Hood
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
| | - Jianxin Bao
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- Center for Aging, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
- The Division of Biology & Biomedical Science and Neuroscience Program, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
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25
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Logerot P, Krützfeldt NOE, Wild JM, Kubke MF. Subdivisions of the auditory midbrain (n. mesencephalicus lateralis, pars dorsalis) in zebra finches using calcium-binding protein immunocytochemistry. PLoS One 2011; 6:e20686. [PMID: 21701681 PMCID: PMC3119058 DOI: 10.1371/journal.pone.0020686] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 05/07/2011] [Indexed: 12/02/2022] Open
Abstract
The midbrain nucleus mesencephalicus lateralis pars dorsalis (MLd) is thought to be the avian homologue of the central nucleus of the mammalian inferior colliculus. As such, it is a major relay in the ascending auditory pathway of all birds and in songbirds mediates the auditory feedback necessary for the learning and maintenance of song. To clarify the organization of MLd, we applied three calcium binding protein antibodies to tissue sections from the brains of adult male and female zebra finches. The staining patterns resulting from the application of parvalbumin, calbindin and calretinin antibodies differed from each other and in different parts of the nucleus. Parvalbumin-like immunoreactivity was distributed throughout the whole nucleus, as defined by the totality of the terminations of brainstem auditory afferents; in other words parvalbumin-like immunoreactivity defines the boundaries of MLd. Staining patterns of parvalbumin, calbindin and calretinin defined two regions of MLd: inner (MLd.I) and outer (MLd.O). MLd.O largely surrounds MLd.I and is distinct from the surrounding intercollicular nucleus. Unlike the case in some non-songbirds, however, the two MLd regions do not correspond to the terminal zones of the projections of the brainstem auditory nuclei angularis and laminaris, which have been found to overlap substantially throughout the nucleus in zebra finches.
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Affiliation(s)
- Priscilla Logerot
- Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Nils O. E. Krützfeldt
- Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - J. Martin Wild
- Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - M. Fabiana Kubke
- Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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26
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Frisina RD, Zhu X. Auditory sensitivity and the outer hair cell system in the CBA mouse model of age-related hearing loss. ACTA ACUST UNITED AC 2010; 2:9-16. [PMID: 21866215 DOI: 10.2147/oaap.s7202] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Age-related hearing loss is a highly prevalent sensory disorder, from both the clinical and animal model perspectives. Understanding of the neurophysiologic, structural, and molecular biologic bases of age-related hearing loss will facilitate development of biomedical therapeutic interventions to prevent, slow, or reverse its progression. Thus, increased understanding of relationships between aging of the cochlear (auditory portion of the inner ear) hair cell system and decline in overall hearing ability is necessary. The goal of the present investigation was to test the hypothesis that there would be correlations between physiologic measures of outer hair cell function (otoacoustic emission levels) and hearing sensitivity (auditory brainstem response thresholds), starting in middle age. For the CBA mouse, a useful animal model of age-related hearing loss, it was found that correlations between these two hearing measures occurred only for high sound frequencies in middle age. However, in old age, a correlation was observed across the entire mouse range of hearing. These findings have implications for improved early detection of progression of age-related hearing loss in middle-aged mammals, including mice and humans, and distinguishing peripheral etiologies from central auditory system decline.
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Affiliation(s)
- Robert D Frisina
- Otolaryngology, Biomedical Engineering, Neurobiology, and Anatomy Departments, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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27
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Cell Biology and Physiology of the Aging Central Auditory Pathway. THE AGING AUDITORY SYSTEM 2010. [DOI: 10.1007/978-1-4419-0993-0_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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28
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Age-related changes in calbindin-D28k, parvalbumin, and calretinin immunoreactivity in the dog main olfactory bulb. Cell Mol Neurobiol 2009; 30:1-12. [PMID: 19533334 DOI: 10.1007/s10571-009-9425-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022]
Abstract
Expression and age-related changes of calbindin-D28k (CB), parvalbumin (PV), and calretinin (CR) in the main olfactory bulb of the dog were investigated by immunohistochemistry and western blot analysis. Neurons that expressed these calcium-binding proteins showed a characteristic laminar distribution. Most of CB-immunoreactive neurons were observed in the glomerular layer (GL) and the inner sublayer of the external plexiform layer (EPL). Most of PV-immunoreactive neurons were observed in the outer sublayer of the EPL. CR-immunoreactive neurons were mainly distributed in the GL and the granule cell layer. With regard to age-related changes, CB-immunoreactive neurons in the GL were stable among all age groups; however, in the EPL they decreased with age. PV-immunoreactive neurons decreased in middle-aged and aged groups. However, CR-immunoreactive neurons were not decreased in middle-aged and aged groups. These results suggest that CB-immunoreactive neurons in the EPL were most sensitive to aging, and that their reduction may be related to aging in the dog.
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29
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Age-related changes in GAD levels in the central auditory system of the rat. Exp Gerontol 2009; 44:161-9. [DOI: 10.1016/j.exger.2008.09.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 09/22/2008] [Accepted: 09/29/2008] [Indexed: 11/22/2022]
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30
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Ouda L, Druga R, Syka J. Changes in parvalbumin immunoreactivity with aging in the central auditory system of the rat. Exp Gerontol 2008; 43:782-9. [DOI: 10.1016/j.exger.2008.04.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/21/2008] [Accepted: 04/01/2008] [Indexed: 10/22/2022]
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31
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Different protein profiles in inferior colliculus and cerebellum: A comparative proteomic study. Neuroscience 2008; 154:233-44. [DOI: 10.1016/j.neuroscience.2008.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 02/13/2008] [Accepted: 02/14/2008] [Indexed: 11/22/2022]
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32
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Sensorineural hearing loss and neural correlates of temporal acuity in the inferior colliculus of the C57BL/6 mouse. J Assoc Res Otolaryngol 2007; 9:90-101. [PMID: 17994264 DOI: 10.1007/s10162-007-0101-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 09/25/2007] [Indexed: 10/22/2022] Open
Abstract
Perception of complex sounds depends on the encoding of the dynamic and static structures within the ongoing stimulus by the auditory system. Aging has been associated with deficits in both areas, thus, the difficulty that the elderly have in speech comprehension could due to hearing loss, or to a loss of temporal sensitivity, or some combination of both. We investigated the effects of sensorineural hearing loss (SNHL) on neural correlates of temporal resolution by recording the responses of inferior colliculus neurons to a gap detection paradigm. We used C57BL/6 (C57) strain of laboratory mouse, which carries the Ahl deafness gene that initiates a progressive high frequency SNHL beginning at about 2 months of age and rapidly progresses to total deafness by 18 months. We compared gap encoding from inferior collicular neurons from young, normal-hearing C57 mice and middle-aged, hearing-impaired, C57 mice, quantifying minimal gap threshold, and recovery functions. The proportion of unit types, spontaneous rates and degree of monotonicity were comparable between young and middle-aged C57 mice. As expected, single unit thresholds were elevated by 30-40 dB in middle-aged C57 mice. However, no significant differences in mean minimal gap thresholds or in the slopes of the gap recovery functions were found between the two age groups. Thus, the results suggest that moderate high frequency SNHL does not affect temporal processing as measured by the gap detection paradigm.
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33
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Zhu X, Vasilyeva ON, Kim S, Jacobson M, Romney J, Waterman MS, Tuttle D, Frisina RD. Auditory efferent feedback system deficits precede age-related hearing loss: contralateral suppression of otoacoustic emissions in mice. J Comp Neurol 2007; 503:593-604. [PMID: 17559088 DOI: 10.1002/cne.21402] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The C57BL/6J mouse has been a useful model of presbycusis, as it displays an accelerated age-related peripheral hearing loss. The medial olivocochlear efferent feedback (MOC) system plays a role in suppressing cochlear outer hair cell (OHC) responses, particularly for background noise. Neurons of the MOC system are located in the superior olivary complex, particularly in the dorsomedial periolivary nucleus (DMPO) and in the ventral nucleus of the trapezoid body (VNTB). We previously discovered that the function of the MOC system declines with age prior to OHC degeneration, as measured by contralateral suppression (CS) of distortion product otoacoustic emissions (DPOAEs) in humans and CBA mice. The present study aimed to determine the time course of age changes in MOC function in C57s. DPOAE amplitudes and CS of DPOAEs were collected for C57s from 6 to 40 weeks of age. MOC responses were observed at 6 weeks but were gone at middle (15-30 kHz) and high (30-45 kHz) frequencies by 8 weeks. Quantitative stereological analyses of Nissl sections revealed smaller neurons in the DMPO and VNTB of young adult C57s compared with CBAs. These findings suggest that reduced neuron size may underlie part of the noteworthy rapid decline of the C57 efferent system. In conclusion, the C57 mouse has MOC function at 6 weeks, but it declines quickly, preceding the progression of peripheral age-related sensitivity deficits and hearing loss in this mouse strain.
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Affiliation(s)
- Xiaoxia Zhu
- Department of Otolaryngology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642-8629, USA
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34
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Tadros SF, D'Souza M, Zettel ML, Zhu X, Lynch-Erhardt M, Frisina RD. Serotonin 2B receptor: Upregulated with age and hearing loss in mouse auditory system. Neurobiol Aging 2007; 28:1112-23. [PMID: 16822592 DOI: 10.1016/j.neurobiolaging.2006.05.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 05/03/2006] [Accepted: 05/09/2006] [Indexed: 12/20/2022]
Abstract
Serotonin (5-HT) is a monoamine neurotransmitter. Serotonin may modulate afferent fiber discharges in the cochlea, inferior colliculus (IC) and auditory cortex. Specific functions of serotonin are exerted upon its interaction with specific receptors; one of those receptors is the serotonin 2B receptor. The aim of this study was to investigate the differences in gene expression of serotonin 2B receptors with age in cochlea and IC, and the possible correlation between gene expression and functional hearing measurements in CBA/CaJ mice. Immunohistochemical examinations of protein expression of IC in mice of different age groups were also performed. Gene expression results showed that serotonin 2B receptor gene was upregulated with age in both cochlea and IC. A significant correlation between gene expression and functional hearing results was established. Immunohistochemical protein expression studies of IC showed more serotonin 2B receptor cells in old mice relative to young adult mice, particularly in the external nucleus. We conclude that serotonin 2B receptors may play a role in the pathogenesis of age-related hearing loss.
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MESH Headings
- Acoustic Stimulation/methods
- Aging
- Analysis of Variance
- Animals
- Auditory Pathways/physiopathology
- Auditory Threshold/physiology
- Dose-Response Relationship, Radiation
- Evoked Potentials, Auditory, Brain Stem/physiology
- Gene Expression Profiling
- Hearing Loss/pathology
- Mice
- Mice, Inbred CBA
- Models, Animal
- Oligonucleotide Array Sequence Analysis/methods
- Otoacoustic Emissions, Spontaneous/physiology
- RNA, Messenger/biosynthesis
- Receptor, Serotonin, 5-HT2B/genetics
- Receptor, Serotonin, 5-HT2B/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Up-Regulation/physiology
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Affiliation(s)
- Sherif F Tadros
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, Rochester, NY 14642-8629, USA
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35
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Embryology and neuropathological examination of central nervous system malformations. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0072-9752(07)87029-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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36
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Gleich O, Hamann I, Kittel MC, Klump GM, Strutz J. Forward masking in gerbils: The effect of age. Hear Res 2007; 223:122-8. [PMID: 17158007 DOI: 10.1016/j.heares.2006.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 11/02/2006] [Accepted: 11/02/2006] [Indexed: 10/23/2022]
Abstract
We investigated forward masking in 21 gerbils as a function of age (5-47 months) using 400ms maskers at 40dB SPL and a 20ms, 2.85kHz probe presented 2.5ms after the masker. Elevated thresholds for the unmasked probe were only observed in animals older than 3 years. Unmasked thresholds showed no significant age-dependent hearing loss in animals below 3 years of age. In these animals without peripheral hearing loss, we found a significant age-dependent increase of masker-induced threshold shift. A regression analysis revealed that threshold shift increased from 23dB in 1 year old gerbils to 37dB in 3 year old animals. Increased forward masking in these animals with no sign of peripheral hearing loss points to a central processing deficit.
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Affiliation(s)
- Otto Gleich
- ENT-Department, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany.
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37
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Friedland DR, Popper P, Eernisse R, Cioffi JA. Differentially expressed genes in the rat cochlear nucleus. Neuroscience 2006; 142:753-68. [PMID: 16905270 DOI: 10.1016/j.neuroscience.2006.06.060] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 05/05/2006] [Accepted: 06/30/2006] [Indexed: 11/27/2022]
Abstract
The cochlear nucleus is the first central pathway involved in the processing of peripheral auditory activity. The anterior ventral cochlear nucleus (AVCN), posterior ventral cochlear nucleus (PVCN) and dorsal cochlear nucleus (DCN) each contain predominant populations of neurons that have been well characterized regarding their morphological and electrophysiological properties. Little is known, however, of the underlying genetic factors that contribute to these properties and the initial steps in auditory processing. Serial analysis of gene expression (SAGE), supported by microarray experiments, was performed on each subdivision of the rat cochlear nucleus to identify genes that may sub-serve specialized roles in the central auditory system. Pair-wise comparisons between SAGE libraries from the AVCN, PVCN and DCN were correlated with microarray experiments to identify individual transcripts with significant differential expression. Twelve highly correlated genes were identified representing cytoskeletal, vesicular, metabolic and g-protein regulating proteins. Among these were Rgs4 which showed higher expression in the DCN, Sst and Cyp11b1 with very high expression in the AVCN and Calb2 with preferential expression in the PVCN. The differential expression of these genes was validated with real-time reverse transcriptase-polymerase chain reaction. These experiments provide a basis for understanding normal auditory processing on a molecular level and a template for investigating changes that may occur in the cochlear nucleus with hearing loss, the generation and percept of tinnitus, and central auditory processing disorders.
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Affiliation(s)
- D R Friedland
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 9200 West Wisconsin Avenue, Milwaukee, WI 53226, USA.
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38
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Willott JF, VandenBosche J, Shimizu T, Ding DL, Salvi R. Effects of exposing gonadectomized and intact C57BL/6J mice to a high-frequency augmented acoustic environment: Auditory brainstem response thresholds and cytocochleograms. Hear Res 2006; 221:73-81. [PMID: 16973316 PMCID: PMC1831842 DOI: 10.1016/j.heares.2006.07.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 07/21/2006] [Accepted: 07/28/2006] [Indexed: 01/16/2023]
Abstract
Gonadectomized and surgically intact adult C57BL/6J (B6) mice of both sexes were exposed for 12h nightly to a high-frequency augmented acoustic environment (AAE): repetitive bursts of a half-octave noise band centered at 20 kHz, 70 dB SPL. The effects of sex, gonadectomy, and AAE treatment on genetic progressive hearing loss (exhibited by B6 mice) were evaluated by obtaining auditory brainstem response thresholds at ages 3-, 6-, and 9-months; hair cell counts (cytocochleograms) were obtained at 9 months. A sex difference in the rate of genetic progressive hearing loss in B6 mice (observed by earlier studies) was confirmed, with females exhibiting a faster rate of threshold elevations and more severe loss of hair cells at age 9 months. Gonadectomy had no consistent effects on the rate or severity of hearing loss in non-exposed mice of either sex. An unexpected finding was that the high-frequency AAE treatment caused additional ABR threshold elevations and hair cell loss. In an earlier study, the same high-frequency AAE treatment on DBA/2J mice ameliorated hearing loss. The most severe AAE-induced losses occurred in surgically intact females, suggesting a potentiating effect of ovarian hormone(s).
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Affiliation(s)
- James F Willott
- Department of Psychology, University of South Florida, 4202 E. Fowler Ave. PCD4118G, Tampa, FL 33620, USA.
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39
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Bazwinsky I, Bidmon HJ, Zilles K, Hilbig H. Characterization of the rhesus monkey superior olivary complex by calcium binding proteins and synaptophysin. J Anat 2006; 207:745-61. [PMID: 16367802 PMCID: PMC1571589 DOI: 10.1111/j.1469-7580.2005.00491.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
This study was performed in order to characterize the main nuclei of the rhesus monkey superior olivary complex by means of antibodies against the calcium binding proteins parvalbumin, calbindin and calretinin and the synaptic vesicle protein synaptophysin. These markers revealed the neuronal morphology and organization of nuclei located within the rhesus monkey superior olivary complex. The architectural details included the distribution of axonal terminals on neurons. The medial superior olivary nucleus was present as a column of neurons. No clear segregation of calretinin-positive terminals was noticed on the medial and lateral dendritic fields of these neurons. The lateral superior olivary nucleus was characterized by a distinct nuclear shape. Calretinin-, parvalbumin- or calbindin-positive terminals contacted somata and dendrites. The medial nucleus of trapezoid body could be clearly differentiated as a distinct region in the rhesus monkey superior olivary complex. Somata of that nucleus showed calbindin- and parvalbumin-labelling whereas somatic calyces of Held were reavealed by calretinin and synaptophysin labelling. The results are discussed with respect to the processing of acoustic information in primate species and their ability to hear high and low frequencies, which is reflected by anatomical correlates.
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Affiliation(s)
- Ivonne Bazwinsky
- Institute of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle, Germany.
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40
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Alvarado JC, Fuentes-Santamaria V, Franklin SR, Brunso-Bechtold JK, Henkel CK. Unilateral cochlear ablation in adult ferrets results in upregulation in calretinin immunostaining in the central nucleus of the inferior colliculus. Neuroscience 2006; 136:957-69. [PMID: 16344163 DOI: 10.1016/j.neuroscience.2005.04.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2005] [Revised: 03/26/2005] [Accepted: 04/05/2005] [Indexed: 10/25/2022]
Abstract
In the present study, unilateral cochlear ablations were performed in adult ferrets in order to determine whether an upregulation of the calretinin immunostained plexus in the central nucleus of the inferior colliculus occurs and if so, what the time course of this upregulation is. Accordingly, the mean gray level and the calretinin-immunostained area of the axonal plexus in the central nucleus of the inferior colliculus were evaluated at 1, 20 and 90 days after cochlear ablation. In unoperated animals, the calretinin-immunostained plexus was bilaterally symmetric. In ablated animals, both the mean gray level and the immunostained area of the plexus increased in the central nucleus of the inferior colliculus contralateral to the lesion compared with both the ipsilateral side and unoperated animals. This upregulation was present 24 h after the ablation and did not change at the two subsequent time points. In a previous study in young ferrets, the immunostained area of the plexus in the central nucleus of the inferior colliculus contralateral to the lesion increased 200% compared with control ferrets [J Comp Neurol 460 (2003) 585], whereas it increased only 33% in adult ferrets. These findings suggest that 1) calretinin upregulation in the contralateral central nucleus of the inferior colliculus following cochlear ablation occurs by 24 h after cochlear ablation and 2) there is an age-related decline in the magnitude of this upregulation after cochlear ablation.
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Affiliation(s)
- J C Alvarado
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA. jalvarad@@wfubmc.edu
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41
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Varghese GI, Zhu X, Frisina RD. Age-related declines in distortion product otoacoustic emissions utilizing pure tone contralateral stimulation in CBA/CaJ mice. Hear Res 2005; 209:60-7. [PMID: 16061336 DOI: 10.1016/j.heares.2005.06.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 06/21/2005] [Indexed: 11/29/2022]
Abstract
One role of the medial olivocochlear (MOC) auditory efferent system is to suppress cochlear outer hair cell (OHC) responses when presented with a contralateral sound. Using distortion product otoacoustic emissions (DPOAEs), the effects of active changes in OHC responses due to the MOC as a function of age can be observed when contralateral stimulation with a pure tone is applied. Previous studies have shown that there are age-related declines of the MOC when broad band noise is presented to the contralateral ear. In this study, we measured age-related changes in CBA/CaJ mice by comparing DPOAE generation with and without a contralateral pure tone at three different frequencies (12, 22, and 37 kHz). Young (n = 16), middle (n = 10) and old-aged (n = 10) CBA mice were tested. DPOAE-grams were obtained using L1 = 65 and L2 = 50 dB SPL, F1/F2 = 1.25, using eight points per octave covering a frequency range from 5.6-44.8 kHz. The pure tone was presented contralaterally at 55 dB SPL. DPOAE-grams and ABR levels indicated age-related hearing loss in the old mice. In addition, there was an overall change in DPOAEs in the middle-aged and old groups relative to the young. Pure tone stimulation was not as effective as a suppressor compared to broadband noise. An increase in pure tone frequency from 12 to 22 kHz induced greater suppression of DPOAEs, but the 37 kHz was least effective. These results indicate that as the mouse ages, there are significant changes in the efficiency of the suppression mechanism as elicited by contralateral narrowband stimuli. These findings reinforce the idea that age-related changes in the MOC or the operating points of OHCs play a role in the progression of presbycusis - age-related hearing loss in mammals.
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Affiliation(s)
- George I Varghese
- Department of Otolaryngology, University of Rochester School of Medicine and Dentistry, NY 14642-8629, USA
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42
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Tadros SF, Frisina ST, Mapes F, Kim S, Frisina DR, Frisina RD. Loss of Peripheral Right-Ear Advantage in Age-Related Hearing Loss. Audiol Neurootol 2004; 10:44-52. [PMID: 15567914 DOI: 10.1159/000082307] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In young adults with normal hearing, the right ear is more sensitive than the left to simple sounds (peripheral right-ear advantage) and to processing complex sounds such as speech (central right-ear advantage). In the present investigation, the effects of hearing loss and aging on this auditory asymmetry were examined at both peripheral and central levels. Audiograms and transient evoked otoacoustic emission (TEOAE) and distortion product otoacoustic emission amplitudes were used to assess cochlear function. The contralateral suppression of TEOAEs was measured to assess the medial olivocochlear efferent system. The Hearing in Noise Test (HINT; binaural speech) was conducted to assess higher central auditory function. A group of aged subjects with normal hearing (flat audiograms) were compared to a group of aged subjects with sloping audiograms (presbycusis). At the cochlear (peripheral) level, the normal hearing group showed significantly higher otoacoustic emission amplitudes for the right ear compared to the left ear, which is consistent with the right-ear dominance normally seen in young adults. However, this finding was reversed in the presbycusic group that showed higher left-ear emission amplitudes. At the brainstem level, the amplitudes of TEOAE contralateral suppression were small and no significant difference was found between the right and left ears in both groups. On the contrary, HINT results showed a continuous dominance of the right ear (left hemisphere) in both groups, which was consistent with previous reports showing that the right hemisphere is more affected by age than the left hemisphere.
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Affiliation(s)
- Sherif F Tadros
- International Center for Hearing and Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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43
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Idrizbegovic E, Bogdanovic N, Willott JF, Canlon B. Age-related increases in calcium-binding protein immunoreactivity in the cochlear nucleus of hearing impaired C57BL/6J mice. Neurobiol Aging 2004; 25:1085-93. [PMID: 15212833 DOI: 10.1016/j.neurobiolaging.2003.11.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2003] [Revised: 10/27/2003] [Accepted: 11/04/2003] [Indexed: 11/17/2022]
Abstract
Aging C57BL/6J (C57) mice (1-30 months old), were used to study calcium-binding protein immunoreactivity (parvalbumin, calbindin and calretinin) in the cochlear nucleus. A quantitative stereological method, the optical fractionator was used to determine the total number of neurons, and the total number of immunostained neurons in the posteroventral- and dorsal cochlear nuclei (PVCN and DCN). A statistically significant age-related decrease of the total number of neurons was found in the PVCN and DCN using Nissl staining. In the DCN, an age-related increase in the total number of parvalbumin-positive neurons was found, while no changes in the total number of calbindin or calretinin positive neurons were demonstrated. In the PVCN, the total number of parvalbumin, calbindin, or calretinin positive neurons remained stable with increasing age. The percentage of parvalbumin, calbindin, and calretinin positive neurons significantly increased in the DCN, and the percentage of parvalbumin and calbindin-positive neurons increased in the PVCN. These findings imply that there is a relative up-regulation of calcium-binding proteins in neurons that had not previously expressed these proteins. This plastic response in the profoundly hearing impaired C57 mouse may be a survival strategy for cochlear nucleus neurons.
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Affiliation(s)
- Esma Idrizbegovic
- Department of Audiology, Huddinge University Hospital, Huddinge, Sweden
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44
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Guimaraes P, Zhu X, Cannon T, Kim S, Frisina RD. Sex differences in distortion product otoacoustic emissions as a function of age in CBA mice. Hear Res 2004; 192:83-9. [PMID: 15157966 DOI: 10.1016/j.heares.2004.01.013] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Accepted: 01/14/2004] [Indexed: 11/17/2022]
Abstract
Age-related hearing loss--presbycusis--is the number one communication problem of the aged. A major contributor to presbycusis is the progressive degeneration of cochlear outer hair cells (OHCs). Distortion product otoacoustic emissions (DPOAEs) are effective in vivo, physiological measures of hearing, assessing the health and functioning of the OHCs in mammals. We and others have previously demonstrated that DPOAE amplitudes decline with age in humans and mice. The present study's objective was to measure age-related declines in the OHCs in CBA mice (slow, progressive age-related hearing loss) by comparing DPOAEs and auditory brainstem responses (ABRs) generated from females and males. Young adult (2.1-2.9 months) and middle-aged CBA (14.0-16.4 months) mice were tested, as well as old CBAs (24.3-29.0 months). DPOAE-grams were obtained with L1 = 65 and L2 = 50 dB SPL, f1/f2 = 1.25, using eight points per octave covering a frequency range from 5.6 to 44.8 kHz (geometric mean frequency). ABRs ranged from 3 to 48 kHz. Analyses revealed that DPOAE levels decreased with age for middle-aged and old male CBAs, but for female CBAs, declines did not occur until old age - after menopause. In contrast, ABR amplitudes for female and male young adult and middle-aged CBAs were the same. Female ABR thresholds were lower than males for old CBAs. In conclusion, we discovered that pre-menopausal CBA female mice have healthier OHCs relative to middle-aged males, but much of this relative advantage is lost post-menopause. Understanding sex differences in age-related sensory disorders will be quite helpful for the goals of preventing, slowing or curing sensory problems in old age for both women and men.
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Affiliation(s)
- Patricia Guimaraes
- Department of Surgery, University of Rochester School of Medicine and Dentistry, NY 14642, USA
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45
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Alvarado JC, Fuentes-Santamaria V, Henkel CK, Brunso-Bechtold JK. Alterations in calretinin immunostaining in the ferret superior olivary complex after cochlear ablation. J Comp Neurol 2004; 470:63-79. [PMID: 14755526 DOI: 10.1002/cne.11038] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, we used image analysis to assess changes in calretinin immunoreactivity in the lateral (LSO) and medial (MSO) superior olivary nuclei in ferrets 2 months after unilateral cochlear ablations at 30-40 days of age, soon after hearing onset. These two nuclei are the first significant sites of binaural convergence in the ascending auditory system, and both receive direct projections from the deafferented cochlear nucleus. Cochlear ablation results in a decrease in the overall level of calretinin immunostaining within the LSO ipsilaterally compared with the contralateral side and with control animals and within the MSO bilaterally compared with control ferrets. In addition, the level of calretinin immunostaining ipsilaterally within neurons in the LSO was significantly less in cochlear ablated than control animals. In contrast, there was no effect of cochlear ablation on the level of calretinin immunostaining within neurons either in the contralateral LSO or in the MSO. These results are consistent with a downregulation in calretinin within the neuropil of MSO bilaterally and LSO ipsilaterally, as well as a downregulation in calretinin within somata in the ipsilateral LSO as a result of unilateral cochlear ablation soon after hearing onset. Thus, cochlear-driven activity appears to affect calcium binding protein levels in both neuropil and neurons within the superior olivary complex.
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Affiliation(s)
- Juan Carlos Alvarado
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1010, USA.
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Jacobson M, Kim S, Romney J, Zhu X, Frisina RD. Contralateral suppression of distortion-product otoacoustic emissions declines with age: a comparison of findings in CBA mice with human listeners. Laryngoscope 2003; 113:1707-13. [PMID: 14520094 DOI: 10.1097/00005537-200310000-00009] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES/HYPOTHESIS The auditory efferent system plays presumed roles in enhancing signals in noise, maintaining the cochlea for optimal acoustic signal processing, and may have a protective role in preserving auditory function in the face of ototoxic events. The objective of the study was to measure age-related changes of the medial olivocochlear efferent system in mice by comparing distortion-product otoacoustic emissions generated with and without contralateral white noise stimulation. Consistent with prior work, distortion-product otoacoustic emissions were typically reduced in magnitude when white noise was presented to the contralateral ear. This contralateral suppression is attributed to activation of the medial olivocochlear efferent system, which has an inhibitory effect on the cochlear hair cell system. By studying contralateral suppression on cochlear output in subjects of different ages, it is possible to describe aging effects on the medial olivocochlear system. STUDY DESIGN CBA mice were divided into three age groups: young adult, middle-aged, and old-aged animals (21, 13, and 22 animals per group, respectively), and auditory brainstem responses were obtained before distortion-product otoacoustic emission testing to assess overall hearing abilities. METHODS 2f1-f2 distortion-product otoacoustic emission recordings were obtained from individual subjects (anesthetized with ketamine/xylazine) in each age group under two conditions: 1) in quiet and 2) in the presence of a contralaterally applied wideband noise. RESULTS Principal findings were that distortion-product otoacoustic emission levels decreased with age for mice in a way similar to humans, when correcting for the absolute difference in life spans. In addition, contralateral suppression declined in middle-aged and old-aged groups relative to the young adults for mice in a manner similar to humans. The contralateral suppression decline at low frequencies preceded that of the decline in distortion-product otoacoustic emissions with age. CONCLUSION Functional decline of the medial olivocochlear efferent system with age precedes outer hair cell degeneration. Loss of medial olivocochlear suppressive function may play a role in the development of presbycusis in both clinical cases and animal models.
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Affiliation(s)
- Michael Jacobson
- Division of Otolaryngology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642-8629, USA
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47
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Wu CK, Nagykery N, Hersh LB, Scinto LFM, Geula C. Selective age-related loss of calbindin-D28k from basal forebrain cholinergic neurons in the common marmoset (Callithrix jacchus). Neuroscience 2003; 120:249-59. [PMID: 12849757 DOI: 10.1016/s0306-4522(03)00248-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A significant number of the cholinergic neurons in the basal forebrain of the primate, but not the rodent brain contain the calcium binding protein calbindin-D28k (CB). Previous experiments in our laboratory have demonstrated a substantial age-related loss of CB from the human basal forebrain cholinergic neurons (BFCN). The present study investigated the possible age-related loss of CB from the BFCN in a non-human primate species, the common marmoset (Callithrix jacchus). Quantitative analysis of matching sections as well as unbiased stereological determination of neuronal number were used in 16 adult marmosets ranging in age between 2 and 15 years. No significant changes were observed in the number of choline acetyltransferase-positive BFCN when a group of young animals (< or =4 years) was compared with a 6-8-year-old group and a 9-15-year-old group. Similarly, no age-related changes were observed in Nissl-stained magnocellular basal forebrain (putatively cholinergic) neurons. In contrast, the BFCN of the two older groups of animals displayed a significant loss of CB. The age-related loss of CB occurred in all sectors of the BFCN, but was greatest in the anterior sector of this cell group. The CB loss was neurochemically specific since the BFCN in the older groups of animals continued to express other markers such as high and low affinity neurotrophin receptors. The age-related loss of CB from the marmoset BFCN was also regionally selective as CB positive neurons in other structures, such as the cerebral cortex and the striatum displayed no apparent age-related changes. These results indicate that the marmoset BFCN display a significant and selective age-related loss of CB reminiscent of that observed in the human. Therefore, the common marmoset represents an appropriate animal model in which the consequences of BFCN CB loss can be investigated in depth. Loss of CB from the aged BFCN is likely to reduce the capacity of these neurons to buffer intracellular calcium and to leave them vulnerable to insults which can result in increased calcium levels. The vulnerability of the CB-negative BFCN in the aged marmoset to various insults which disturb calcium homeostasis remains to be investigated.
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Affiliation(s)
- C-K Wu
- Laboratory for Neurodegenerative and Aging Research, Department of Medicine, Harvard Medical School and Division of Gerontology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Burlington Research Facility, Boston, MA 02215, USA
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Zettel ML, O'Neill WE, Trang TT, Frisina RD. The effects of early bilateral deafening on calretinin expression in the dorsal cochlear nucleus of aged CBA/CaJ mice. Hear Res 2003; 183:57-66. [PMID: 13679138 DOI: 10.1016/s0378-5955(03)00216-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of this study was to test the hypothesis that calretinin (CR) levels in the aged mouse auditory brainstem depend upon hearing ability. Old animals with good hearing, and thus higher sound-evoked activity levels, were predicted to have higher levels of CR immunoreactivity than old animals with hearing loss. CR immunoreactivity was analyzed in the deep layer (layer III) of the dorsal cochlear nucleus (DCN) in CBA/CaJ mice that were bilaterally deafened at 3 months of age with kanamycin, and then aged until 24 months. This manipulation partially mimics the lack of sound-evoked auditory activity experienced by old C57BL/6J mice, who are deaf at 24 months of age (but show residual hearing at 15 months) and have lower levels of CR immunoreactivity than old CBA mice with normal hearing [Hear. Res. 158 (2001) 131]. Cell counts revealed that the density of CR+ cells in DCN layer III of the deafened CBA mice was statistically different from old intact CBA mice raised under identical conditions. Old deafened CBAs showed a decline of 47% in the mean density of CR+ cells compared to old hearing CBAs, thus supporting the hypothesis. Interestingly, while there tended to be fewer CR+ cells in the old deaf C57s as compared to young C57s and young and old CBAs with normal hearing, the difference was not statistically significant. It is possible that the residual hearing of C57 mice at 15 months may provide sufficient auditory input to maintain CR at levels higher than CBA mice that are deafened completely at 3 months of age, and are profoundly deaf for a much longer time (21 months).
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Affiliation(s)
- Martha L Zettel
- Department of Surgery, University of Rochester, School of Medicine and Dentistry, Rochester, NY 14642-8629, USA.
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Fuentes-Santamaria V, Alvarado JC, Brunso-Bechtold JK, Henkel CK. Upregulation of calretinin immunostaining in the ferret inferior colliculus after cochlear ablation. J Comp Neurol 2003; 460:585-96. [PMID: 12717716 DOI: 10.1002/cne.10676] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In many systems, including ascending auditory pathways, calcium-binding proteins are markers of specific neuronal circuits. Previous studies suggest that calretinin immunostaining may be a specific marker for circuits in the inferior colliculus (IC) that code timing information. We undertook experiments to determine the changes in calretinin immunostaining in the IC that take place in response to cochlear ablation. Cochlear ablation was performed unilaterally in ferrets just after hearing onset. Animals survived for 2-3 months after ablation and brains were then processed for calretinin immunocytochemistry. The mean optical density and stained area of the calretinin immunopositive plexus in the IC were determined for five coronal sections through the right and left IC. In controls (n = 3), measurements of these parameters in the central nucleus of the IC showed symmetry between the two sides. In experimental animals (n = 8) the calretinin immunopositive plexus contralateral to the cochlear ablation was denser and larger than that in either the ipsilateral IC or in the IC of control animals. The calretinin plexus in the ipsilateral IC was slightly less dense and smaller than in controls but the differences did not reach statistical significance. IC volume measurements and synaptophysin immunostaining analysis in the central nucleus of the IC revealed no statistical differences between ablated and control animals or between the two sides in ablated animals. The significant increase in both mean optical density and immunostained area of the calretinin plexus in the IC contralateral to the cochlear ablation may reflect an upregulation in calretinin expression in the nuclei that contribute to this plexus.
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Affiliation(s)
- Verónica Fuentes-Santamaria
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1010, USA
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Idrizbegovic E, Bogdanovic N, Viberg A, Canlon B. Auditory peripheral influences on calcium binding protein immunoreactivity in the cochlear nucleus during aging in the C57BL/6J mouse. Hear Res 2003; 179:33-42. [PMID: 12742236 DOI: 10.1016/s0378-5955(03)00076-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The C57BL/6J (C57) mouse was selected as a suitable model for early presbyacusis to determine if there were correlations between peripheral pathology (spiral ganglion loss, inner and outer hair cell loss) and calcium binding immunoreactivity in the cochlear nucleus during aging. The quantitative stereological method, the optical fractionator, was used for determining the total number of neurons and calcium binding immunopositive neurons (calbindin, parvalbumin and calretinin) during aging in the posteroventral- and dorsal cochlear nucleus (PVCN and DCN) in C57 mice. Comparing 30-month-old to 1-month-old C57 mice, a percent increase in parvalbumin and calbindin immunoreactivity was evident in both the PVCN and DCN. Correlations were made between peripheral pathology (spiral ganglion and inner and outer hair cell loss) and calcium binding protein expression. Significant correlations between cochlear pathology and the percentage of parvalbumin and calretinin immunoreactive neurons were demonstrated in the DCN. Moreover, significant correlations were found between cochlear pathology and parvalbumin and calbindin in the PVCN. In summary, the findings imply that degenerative changes in the auditory periphery can modulate neuronal homeostasis by increasing calcium binding proteins in the PVCN and DCN during aging. Taken together, these findings suggest a role for calcium binding proteins in protecting against age-induced calcium toxicity.
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Affiliation(s)
- Esma Idrizbegovic
- Department of Audiology, Huddinge University Hospital, Karolinska Institutet, Stockholm, Sweden. esma.idrizbegovic.hs.se
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