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Freiler MK, Deckard ML, Proffitt MR, Troy Smith G. Differential expression of steroid-related genes across electrosensory brain regions in two sexually dimorphic species of electric knifefish. Gen Comp Endocrinol 2024; 355:114549. [PMID: 38797340 PMCID: PMC11265523 DOI: 10.1016/j.ygcen.2024.114549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024]
Abstract
The production of communication signals can be modulated by hormones acting on the brain regions that regulate these signals. However, less is known about how signal perception is regulated by hormones. The electrocommunication signals of weakly electric fishes are sexually dimorphic, sensitive to hormones, and vary across species. The neural circuits that regulate the production and perception of these signals are also well-characterized, and electric fishes are thus an excellent model to examine the neuroendocrine regulation of sensorimotor mechanisms of communication. We investigated (1) whether steroid-related genes are expressed in sensory brain regions that process communication signals; and (2) whether this expression differs across sexes and species that have different patterns of sexual dimorphism in their signals. Apteronotus leptorhynchus and Apteronotus albifrons produce continuous electric organ discharges (EODs) that are used for communication. Two brain regions, the electrosensory lateral line lobe (ELL) and the dorsal torus semicircularis (TSd), process inputs from electroreceptors to allow fish to detect and discriminate electrocommunication signals. We used qPCR to quantify the expression of genes for two androgen receptors (ar1, ar2), two estrogen receptors (esr1, esr2b), and aromatase (cyp19a1b). Four out of five steroid-related genes were expressed in both sensory brain regions, and their expression often varied between sexes and species. These results suggest that expression of steroid-related genes in the brain may differentially influence how EOD signals are encoded across species and sexes, and that gonadal steroids may coordinately regulate central circuits that control both the production and perception of EODs.
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Affiliation(s)
- Megan K Freiler
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States.
| | - Mikayla L Deckard
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States
| | - Melissa R Proffitt
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States
| | - G Troy Smith
- Department of Biology, Indiana University, 1001 E 3(rd) St., Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, 409 N. Park Ave, Bloomington, IN 47405, United States
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Capshaw G, Brown AD, Peña JL, Carr CE, Christensen-Dalsgaard J, Tollin DJ, Womack MC, McCullagh EA. The continued importance of comparative auditory research to modern scientific discovery. Hear Res 2023; 433:108766. [PMID: 37084504 PMCID: PMC10321136 DOI: 10.1016/j.heares.2023.108766] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/23/2023] [Accepted: 04/05/2023] [Indexed: 04/23/2023]
Abstract
A rich history of comparative research in the auditory field has afforded a synthetic view of sound information processing by ears and brains. Some organisms have proven to be powerful models for human hearing due to fundamental similarities (e.g., well-matched hearing ranges), while others feature intriguing differences (e.g., atympanic ears) that invite further study. Work across diverse "non-traditional" organisms, from small mammals to avians to amphibians and beyond, continues to propel auditory science forward, netting a variety of biomedical and technological advances along the way. In this brief review, limited primarily to tetrapod vertebrates, we discuss the continued importance of comparative studies in hearing research from the periphery to central nervous system with a focus on outstanding questions such as mechanisms for sound capture, peripheral and central processing of directional/spatial information, and non-canonical auditory processing, including efferent and hormonal effects.
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Affiliation(s)
- Grace Capshaw
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Andrew D Brown
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA 98105, USA
| | - José L Peña
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Catherine E Carr
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Daniel J Tollin
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Molly C Womack
- Department of Biology, Utah State University, Logan, UT 84322, USA.
| | - Elizabeth A McCullagh
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078, USA.
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3
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Aloufi N, Heinrich A, Marshall K, Kluk K. Sex differences and the effect of female sex hormones on auditory function: a systematic review. Front Hum Neurosci 2023; 17:1077409. [PMID: 37151900 PMCID: PMC10161575 DOI: 10.3389/fnhum.2023.1077409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 03/30/2023] [Indexed: 05/09/2023] Open
Abstract
Aims First, to discuss sex differences in auditory function between women and men, and whether cyclic fluctuations in levels of female sex hormones (i.e., estradiol and progesterone) affect auditory function in pre-menopausal and post-menopausal women. Second, to systematically review the literature concerning the discussed patterns in order to give an overview of the methodologies used in research. Last, to identify the gap in knowledge and to make recommendations for future work. Methods for the systematic review Population, Exposure, Control, Outcome and Study design (PECOS) criteria were used in developing the review questions. The review protocol follows the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was pre-registered in the Prospective Register of Systematic Reviews (PROSPERO; CRD42020201480). Data Sources: EMBASE, PubMed, MEDLINE (Ovid), PsycINFO, ComDisDome, CINAHL, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) via Cochrane Library, and scanning reference lists of relevant studies, and internet resources (i.e., Mendeley) were used. Only studies published between 1999 and 2022, in English, or in English translation, were included. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS). Results Sex differences: Women had more sensitive hearing (measured at the level of peripheral and central auditory system) than men. Cyclic fluctuations: Auditory function in women fluctuated during the menstrual cycle, while no such fluctuations in men over the same time period were reported. Hearing sensitivity improved in women during the late follicular phase, and decrease during the luteal phase, implying an effect of female sex hormones, although the specific effects of estradiol and progesterone fluctuations on the central auditory system remain unclear. Hearing sensitivity in women declined rapidly at the onset of menopause. Conclusion The review has shown the following. Consistent sex differences exist in auditory function across the auditory pathway with pre-menopausal women often showing better function than age-matched men. Moreover, pre-menopausal women show fluctuations in hearing function across the menstrual cycle with a better function during the peak of estradiol or when the ratio of estradiol to progesterone is high. Third, menopause marks the onset of hearing loss in women, characterized by a rapid decline in hearing sensitivity and a more pronounced loss than in age-matched men. Finally, the systematic review highlights the need for well-designed and -controlled studies to evaluate the influence of estradiol and progesterone on hearing by consistently including control groups (e.g., age-matched man), using objective tests to measure hormonal levels (e.g., in saliva or blood), and by testing participants at different points across the menstrual cycle. Systematic review registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020201480, identifier CRD42020201480.
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Affiliation(s)
- Nada Aloufi
- Manchester Centre for Audiology and Deafness, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Health Sciences, University of Manchester, Manchester, United Kingdom
- College of Medical Rehabilitation Sciences, Taibah University, Medina, Saudi Arabia
| | - Antje Heinrich
- Manchester Centre for Audiology and Deafness, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Health Sciences, University of Manchester, Manchester, United Kingdom
| | - Kay Marshall
- Division of Pharmacy and Optometry, Faculty of Biology, School of Health Sciences, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Karolina Kluk
- Manchester Centre for Audiology and Deafness, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Health Sciences, University of Manchester, Manchester, United Kingdom
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Williamson TT, Zhu X, Pineros J, Ding B, Frisina RD. Understanding hormone and hormone therapies' impact on the auditory system. J Neurosci Res 2020; 98:1721-1730. [PMID: 32026519 DOI: 10.1002/jnr.24588] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 12/22/2019] [Accepted: 01/17/2020] [Indexed: 11/10/2022]
Abstract
Hormones such as estrogen, progesterone, and aldosterone all demonstrate vital roles in sustaining auditory function through either the maintenance of cochlear neurons, up/down regulation of critical molecules (i.e., IGF-1, BDNF, etc.), or generation of the endocochlear potential. With disease and/or age, hormone expression begins to decline drastically, which ultimately affects cochlear structures and the integrity of cochlear cells. The following review explores the latest findings as well as realistic outcomes for hormone therapy treatment in the auditory system. This information could serve as a potential guide for patients considering hormone therapy as a medicinal choice to alleviate the signs of onset of presbycusis-age-related hearing loss. Additional scientific investigations could also be carried out to further enhance recent findings.
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Affiliation(s)
- Tanika T Williamson
- Department of Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.,Department of Chemical & Biological Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.,Department of Chemical & Biological Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Jennifer Pineros
- Department of Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.,Department of Chemical & Biological Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Bo Ding
- Department of Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
| | - Robert D Frisina
- Department of Medical Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.,Department of Chemical & Biological Engineering, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA.,Department of Communication Sciences & Disorders, Global Center for Hearing & Speech Research, University of South Florida, Tampa, FL, USA
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Falah M, Houshmand M, Najafi M, Balali M, Mahmoudian S, Asghari A, Emamdjomeh H, Farhadi M. The potential role for use of mitochondrial DNA copy number as predictive biomarker in presbycusis. Ther Clin Risk Manag 2016; 12:1573-1578. [PMID: 27799778 PMCID: PMC5077262 DOI: 10.2147/tcrm.s117491] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES Age-related hearing impairment, or presbycusis, is the most common communication disorder and neurodegenerative disease in the elderly. Its prevalence is expected to increase, due to the trend of growth of the elderly population. The current diagnostic test for detection of presbycusis is implemented after there has been a change in hearing sensitivity. Identification of a pre-diagnostic biomarker would raise the possibility of preserving hearing sensitivity before damage occurs. Mitochondrial dysfunction, including the production of reactive oxygen species and induction of expression of apoptotic genes, participates in the progression of presbycusis. Mitochondrial DNA sequence variation has a critical role in presbycusis. However, the nature of the relationship between mitochondrial DNA copy number, an important biomarker in many other diseases, and presbycusis is undetermined. METHODS Fifty-four subjects with presbycusis and 29 healthy controls were selected after ear, nose, throat examination and pure-tone audiometry. DNA was extracted from peripheral blood samples. The copy number of mitochondrial DNA relative to the nuclear genome was measured by quantitative real-time polymerase chain reaction. RESULTS Subjects with presbycusis had a lower median mitochondrial DNA copy number than healthy subjects and the difference was statistically significant (P=0.007). Mitochondrial DNA copy number was also significantly associated with degree of hearing impairment (P=0.025) and audiogram configuration (P=0.022). CONCLUSION The findings of this study suggest that lower mitochondrial DNA copy number is responsible for presbycusis through alteration of mitochondrial function. Moreover, the significant association of mitochondrial DNA copy number in peripheral blood samples with the degree of hearing impairment and audiogram configuration has potential for use as a standard test for presbycusis, providing the possibility of the development of an easy-to-use biomarker for the early detection of this condition.
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Affiliation(s)
- Masoumeh Falah
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran; Cellular and Molecular Research Center, Biochemistry Department, Iran University of Medical Sciences, Tehran, Iran
| | - Massoud Houshmand
- Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Mohammad Najafi
- Cellular and Molecular Research Center, Biochemistry Department, Iran University of Medical Sciences, Tehran, Iran
| | - Maryam Balali
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
| | - Saeid Mahmoudian
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
| | - Alimohamad Asghari
- Skull base research center, Iran University of Medical Sciences, Tehran, Iran
| | - Hessamaldin Emamdjomeh
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Farhadi
- ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences, Tehran, Iran
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Overton JA, Recanzone GH. Effects of aging on the response of single neurons to amplitude-modulated noise in primary auditory cortex of rhesus macaque. J Neurophysiol 2016; 115:2911-23. [PMID: 26936987 DOI: 10.1152/jn.01098.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 03/02/2016] [Indexed: 12/13/2022] Open
Abstract
Temporal envelope processing is critical for speech comprehension, which is known to be affected by normal aging. Whereas the macaque is an excellent animal model for human cerebral cortical function, few studies have investigated neural processing in the auditory cortex of aged, nonhuman primates. Therefore, we investigated age-related changes in the spiking activity of neurons in primary auditory cortex (A1) of two aged macaque monkeys using amplitude-modulated (AM) noise and compared these responses with data from a similar study in young monkeys (Yin P, Johnson JS, O'Connor KN, Sutter ML. J Neurophysiol 105: 582-600, 2011). For each neuron, we calculated firing rate (rate code) and phase-locking using phase-projected vector strength (temporal code). We made several key findings where neurons in old monkeys differed from those in young monkeys. Old monkeys had higher spontaneous and driven firing rates, fewer neurons that synchronized with the AM stimulus, and fewer neurons that had differential responses to AM stimuli with both a rate and temporal code. Finally, whereas rate and temporal tuning functions were positively correlated in young monkeys, this relationship was lost in older monkeys at both the population and single neuron levels. These results are consistent with considerable evidence from rodents and primates of an age-related decrease in inhibition throughout the auditory pathway. Furthermore, this dual coding in A1 is thought to underlie the capacity to encode multiple features of an acoustic stimulus. The apparent loss of ability to encode AM with both rate and temporal codes may have consequences for stream segregation and effective speech comprehension in complex listening environments.
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Affiliation(s)
| | - Gregg H Recanzone
- Center for Neuroscience, University of California, Davis, California; and Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
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7
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Buniello A, Ingham NJ, Lewis MA, Huma AC, Martinez-Vega R, Varela-Nieto I, Vizcay-Barrena G, Fleck RA, Houston O, Bardhan T, Johnson SL, White JK, Yuan H, Marcotti W, Steel KP. Wbp2 is required for normal glutamatergic synapses in the cochlea and is crucial for hearing. EMBO Mol Med 2016; 8:191-207. [PMID: 26881968 PMCID: PMC4772953 DOI: 10.15252/emmm.201505523] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/18/2015] [Accepted: 12/21/2015] [Indexed: 01/01/2023] Open
Abstract
WBP2 encodes the WW domain-binding protein 2 that acts as a transcriptional coactivator for estrogen receptor α (ESR1) and progesterone receptor (PGR). We reported that the loss of Wbp2 expression leads to progressive high-frequency hearing loss in mouse, as well as in two deaf children, each carrying two different variants in the WBP2 gene. The earliest abnormality we detect in Wbp2-deficient mice is a primary defect at inner hair cell afferent synapses. This study defines a new gene involved in the molecular pathway linking hearing impairment to hormonal signalling and provides new therapeutic targets.
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Affiliation(s)
- Annalisa Buniello
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Neil J Ingham
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Morag A Lewis
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Andreea C Huma
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Raquel Martinez-Vega
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain Centre for Biomedical Network Research on Rare Diseases (CIBERER), Unit 761, Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Varela-Nieto
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain Centre for Biomedical Network Research on Rare Diseases (CIBERER), Unit 761, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, London, UK
| | - Oliver Houston
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Tanaya Bardhan
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Jacqueline K White
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Huijun Yuan
- Medical Genetics Center, Southwest Hospital Third Military Medical University, Chongqing, China
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Karen P Steel
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
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8
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Dietrich AK, Humphreys GI, Nardulli AM. Expression of estrogen receptor α in the mouse cerebral cortex. Mol Cell Endocrinol 2015; 406:19-26. [PMID: 25700604 PMCID: PMC4773199 DOI: 10.1016/j.mce.2015.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 12/15/2022]
Abstract
Although estrogen receptor alpha (ERα) and 17β-estradiol play critical roles in protecting the cerebral cortex from ischemia-induced damage, there has been some controversy about the expression of ERα in this region of the brain. We have examined ERα mRNA and protein levels in the cerebral cortices of female mice at postnatal days 5 and 17 and at 4, 13, and 18 months of age. We found that although ERα transcript levels declined from postnatal day 5 through 18 months of age, ERα protein levels remained stable. Importantly, expression of the E2-regulated progesterone receptor gene was sustained in younger and in older females suggesting that age-related changes in estrogen responsiveness in the cerebral cortex are not due to the absence of ERα protein.
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Affiliation(s)
- Alicia K Dietrich
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Gwendolyn I Humphreys
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Ann M Nardulli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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Asaba A, Hattori T, Mogi K, Kikusui T. Sexual attractiveness of male chemicals and vocalizations in mice. Front Neurosci 2014; 8:231. [PMID: 25140125 PMCID: PMC4122165 DOI: 10.3389/fnins.2014.00231] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 07/14/2014] [Indexed: 12/04/2022] Open
Abstract
Male-female interaction is important for finding a suitable mating partner and for ensuring reproductive success. Male sexual signals such as pheromones transmit information and social and sexual status to females, and exert powerful effects on the mate preference and reproductive biology of females. Likewise, male vocalizations are attractive to females and enhance reproductive function in many animals. Interestingly, females' preference for male pheromones and vocalizations is associated with their genetic background, to avoid inbreeding. Moreover, based on acoustic cues, olfactory signals have significant effects on mate choice in mice, suggesting mate choice involves multisensory integration. In this review, we synopsize the effects of both olfactory and auditory cues on female behavior and neuroendocrine functions. We also discuss how these male signals are integrated and processed in the brain to regulate behavior and reproductive function.
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Affiliation(s)
- Akari Asaba
- Department of Animal Science and Biotechnology, Graduate School of Veterinary Medicine, Azabu University Kanagawa, Japan
| | - Tatsuya Hattori
- Department of Animal Science and Biotechnology, Graduate School of Veterinary Medicine, Azabu University Kanagawa, Japan
| | - Kazutaka Mogi
- Department of Animal Science and Biotechnology, Graduate School of Veterinary Medicine, Azabu University Kanagawa, Japan
| | - Takefumi Kikusui
- Department of Animal Science and Biotechnology, Graduate School of Veterinary Medicine, Azabu University Kanagawa, Japan
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Caras ML. Estrogenic modulation of auditory processing: a vertebrate comparison. Front Neuroendocrinol 2013; 34:285-99. [PMID: 23911849 PMCID: PMC3788044 DOI: 10.1016/j.yfrne.2013.07.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 07/18/2013] [Accepted: 07/21/2013] [Indexed: 11/30/2022]
Abstract
Sex-steroid hormones are well-known regulators of vocal motor behavior in several organisms. A large body of evidence now indicates that these same hormones modulate processing at multiple levels of the ascending auditory pathway. The goal of this review is to provide a comparative analysis of the role of estrogens in vertebrate auditory function. Four major conclusions can be drawn from the literature: First, estrogens may influence the development of the mammalian auditory system. Second, estrogenic signaling protects the mammalian auditory system from noise- and age-related damage. Third, estrogens optimize auditory processing during periods of reproductive readiness in multiple vertebrate lineages. Finally, brain-derived estrogens can act locally to enhance auditory response properties in at least one avian species. This comparative examination may lead to a better appreciation of the role of estrogens in the processing of natural vocalizations and mayprovide useful insights toward alleviating auditory dysfunctions emanating from hormonal imbalances.
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Affiliation(s)
- Melissa L Caras
- Neurobiology and Behavior Graduate Program, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA; Virginia Merrill Bloedel Hearing Research Center, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA.
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11
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Abstract
Sex steroids modulate vertebrate sensory processing, but the impact of circulating hormone levels on forebrain function remains unclear. We tested the hypothesis that circulating sex steroids modulate single-unit responses in the avian telencephalic auditory nucleus, field L. We mimicked breeding or nonbreeding conditions by manipulating plasma 17β-estradiol levels in wild-caught female Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii). Extracellular responses of single neurons to tones and conspecific songs presented over a range of intensities revealed that estradiol selectively enhanced auditory function in cells that exhibited monotonic rate level functions to pure tones. In these cells, estradiol treatment increased spontaneous and maximum evoked firing rates, increased pure tone response strengths and sensitivity, and expanded the range of intensities over which conspecific song stimuli elicited significant responses. Estradiol did not significantly alter the sensitivity or dynamic ranges of cells that exhibited non-monotonic rate level functions. Notably, there was a robust correlation between plasma estradiol concentrations in individual birds and physiological response properties in monotonic, but not non-monotonic neurons. These findings demonstrate that functionally distinct classes of anatomically overlapping forebrain neurons are differentially regulated by sex steroid hormones in a dose-dependent manner.
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Charitidi K, Meltser I, Canlon B. Estradiol treatment and hormonal fluctuations during the estrous cycle modulate the expression of estrogen receptors in the auditory system and the prepulse inhibition of acoustic startle response. Endocrinology 2012; 153:4412-21. [PMID: 22778224 DOI: 10.1210/en.2012-1416] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Estrogens' effects on hearing are documented across species, but the responsible molecular mechanisms remain unknown. The presence of estrogen receptors (ER) throughout the auditory system offers a potential pathway of direct estrogenic effects on auditory function, but little is known about how each ER's expression is regulated by the overall hormonal status of the body. In the present study, we determined the effects of ovariectomy and chronic 17β-estradiol treatment on mRNA and protein expression of ERα and ERβ in peripheral (cochlea) and central (inferior colliculus) auditory structures of mice, as well as on auditory-related behavior using the acoustic startle response (ASR), prepulse inhibition (PPI), and habituation of the startle response. 17β-Estradiol treatment down-regulated ERα but not ERβ and increased PPI and latency of the ASR. Neither the magnitude nor the habituation of ASR was affected. Furthermore, ER's mRNA and protein expression in the inner ear were analyzed throughout the estrous cycle (proestrus, estrus, metestrus, and diestrus), revealing a negative correlation of circulating estrogens with ERα expression, whereas ERβ was stable. Our findings show that ER not only are present in both the peripheral and central auditory system but also that circulating estrogen levels down-regulate ERα expression in the auditory system and affect PPI and the latency of ASR, suggesting a key role of ERα as a hormone-induced modulator of the auditory system and behavior.
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Affiliation(s)
- Konstantina Charitidi
- Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers Väg 8, Stockholm 17177, Sweden
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Corbitt C, Farinelli F, Brownell WE, Farrell B. Tonotopic relationships reveal the charge density varies along the lateral wall of outer hair cells. Biophys J 2012; 102:2715-24. [PMID: 22735521 DOI: 10.1016/j.bpj.2012.04.054] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 04/27/2012] [Accepted: 04/30/2012] [Indexed: 01/12/2023] Open
Abstract
Outer hair cells amplify and improve the frequency selectivity of sound within the mammalian cochlea through a sound-evoked receptor potential that induces an electromechanical response in their lateral wall membrane. We experimentally show that the membrane area and linear membrane capacitance of outer hair cells increases exponentially with the electrically evoked voltage-dependent charge movement (Q(T)) and peak membrane capacitance (C(peak)). We determine the size of the different functional regions (e.g., lateral wall, synaptic basal pole) of the polarized cells from the tonotopic relationships. We then establish that Q(T) and C(peak) increase with the logarithm of the lateral wall area (A(LW)) and determine from the functions that the charge (σ(LW,) pC/μm(2)) and peak (ρ(LW,) pF/μm(2)) densities vary inversely with A(LW) (σ(LW) = 1.3/A(LW) and ρ(LW) = 9/A(LW)). This shows contrary to conventional wisdom that σ(LW) and ρ(LW) are not constant along the length of an individual outer hair cell.
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Affiliation(s)
- Christian Corbitt
- Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USA
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