1
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Mey M, Bhatta S, Suresh S, Labrador LM, Piontkivska H, Casadesus G. Therapeutic benefits of central LH receptor agonism in the APP/PS1 AD model involve trophic and immune regulation and are reproductive status dependent. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167165. [PMID: 38653355 DOI: 10.1016/j.bbadis.2024.167165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/02/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
The mechanisms that underly reproductive hormone effects on cognition, neuronal plasticity, and AD risk, particularly in relation to gonadotropin LH receptor (LHCGR) signaling, remain poorly understood. To address this gap in knowledge and clarify the impact of circulating steroid hormones on the therapeutic effects of CNS LHCGR activation, we delivered the LHCGR agonist human chorionic gonadotropin (hCG) intracerebroventricularly (ICV) and evaluated functional, structural, plasticity-related signaling cascades, Aβ pathology, and transcriptome differences in reproductively intact and ovariectomized (OVX) APP/PS1 AD female mice. Here we demonstrate that CNS hCG delivery restored function to wild-type levels only in OVX APP/PS1 mice. Spine density was increased in all hCG treated groups independently of reproductive status. Notably, increases in BDNF signaling and cognition, were selectively upregulated only in the OVX hCG-treated group. RNA sequencing analyses identified a significant increase in peripheral myeloid and pro-inflammatory genes within the hippocampi of the OVX group that were completely reversed by hCG treatment, identifying a potential mechanism underlying the selective therapeutic effect of LHCGR activation. Interestingly, in intact mice, hCG administration mimicked the effects of gonadectomy. Together, our findings indicate that CNS LHCGR agonism in the post-menopausal context is beneficial through trophic and immune mechanisms. Our findings also underscore the presence of a steroid-LHCGR mechanistic interaction that is unexplored yet potentially meaningful to fully understand "post-menopausal" brain function and CNS hormone treatment response.
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Affiliation(s)
- Megan Mey
- Kent State University, Kent, OH 44240, United States of America
| | - Sabina Bhatta
- Case Western Reserve University, Cleveland, OH 44106, United States of America
| | - Sneha Suresh
- University of Florida, Gainesville, FL 32606, United States of America
| | | | | | - Gemma Casadesus
- University of Florida, Gainesville, FL 32606, United States of America.
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2
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Mey M, Bhatta S, Suresh S, Montero Labrador L, Piontkivska H, Casadesus G. The LH receptor regulates hippocampal spatial memory and restores dendritic spine density in ovariectomized APP/PS1 AD mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573087. [PMID: 38187770 PMCID: PMC10769359 DOI: 10.1101/2023.12.22.573087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Activation of the luteinizing hormone receptor (LHCGR) rescues spatial memory function and spine density losses associated with gonadectomy and high circulating gonadotropin levels in females. However, whether this extends to the AD brain or the mechanisms that underlie these benefits remain unknown. To address this question, we delivered the LHCGR agonist human chorionic gonadotropin (hCG) intracerebroventricularly (ICV), under reproductively intact and ovariectomized conditions to mimic the post-menopausal state in the APP/PS1mouse brain. Cognitive function was tested using the Morris water maze task, and hippocampal dendritic spine density, Aβ pathology, and signaling changes associated with these endpoints were determined to address mechanisms. Here we show that central LHCGR activation restored function in ovariectomized APP/PS1 female mice to wild-type levels without altering Aβ pathology. LHCGR activation increased hippocampal dendritic spine density regardless of reproductive status, and this was mediated by BDNF-dependent and independent signaling. We also show that ovariectomy in the APP/PS1 brain elicits an increase in peripherally derived pro-inflammatory genes which are inhibited by LHCGR activation. This may mediate reproductive status specific effects of LHCGR agonism on cognitive function and BDNF expression. Together, this work highlights the relevance of the LHCGR on cognition and its therapeutic potential in the "menopausal" AD brain.
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3
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Bhargava S, Shetye K, Shewale S, Sawant N, Sagarkar S, Subhedar N. Mate calling alters expression of neuropeptide, cocaine- and amphetamine- regulated transcript (CART) in the brain of male frog Microhyla nilphamariensis. Neuropeptides 2023; 102:102380. [PMID: 37690194 DOI: 10.1016/j.npep.2023.102380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/22/2023] [Accepted: 09/03/2023] [Indexed: 09/12/2023]
Abstract
Croaking is a unique component of reproductive behaviour in amphibians which plays a key role in intraspecies communication and mate evaluation. While gonadal hormones are known to induce croaking, central regulation of sound production is less studied. Croaking is a dramatic, transient activity that sets apart an animal from non-croaking individuals. Herein, we aim at examining the profile of the neuropeptide cocaine- and amphetamine-regulated transcript (CART) in actively croaking and non-croaking frog Microhyla nilphamariensis. In anurans, this peptide is widely expressed in the areas inclusive of acoustical nuclei as well as areas relevant to reproduction. CART immunoreactivity was far more in the preoptic area (POA), anteroventral tegmentum (AV), ventral hypothalamus (vHy), pineal (P) and pituitary gland of croaking frog compared to non-croaking animals. On similar lines, tissue fragments collected from the mid region of the brain inclusive of POA, vHy, AV, pineal and pituitary gland of croaking frog showed upregulation of CART mRNA. However, CART immunoreactivity in the neuronal perikarya of raphe (Ra) was completely abolished during croaking activity. The data suggest that CART signaling in the brain may be an important player in mediating croaking behaviour in the frog.
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Affiliation(s)
- Shobha Bhargava
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind, Pune 411 007, India.
| | - Ketaki Shetye
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind, Pune 411 007, India
| | - Swapnil Shewale
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind, Pune 411 007, India
| | - Nitin Sawant
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind, Pune 411 007, India
| | - Sneha Sagarkar
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind, Pune 411 007, India
| | - Nishikant Subhedar
- Indian Institute of Science Education and Research, Ganeshkhind, Pune 411 008, India
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4
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Szymanska K, Zaobidna E, Rytelewska E, Mlyczynska E, Kurowska P, Dobrzyn K, Kiezun M, Kaminska B, Smolinska N, Rak A, Kaminski T. Visfatin in the porcine pituitary gland: expression and regulation of secretion during the oestrous cycle and early pregnancy. Sci Rep 2023; 13:18253. [PMID: 37880346 PMCID: PMC10600231 DOI: 10.1038/s41598-023-45255-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
Visfatin is a multifunctional protein which, besides the control of energy homeostasis, seems to be also involved in the regulation of female fertility through the influence on the endocrine hypothalamus-pituitary-gonadal axis, including the pituitary. The aim of this study was to investigate the expression of visfatin mRNA and protein in the anterior (AP) and posterior pituitary lobes of the pig during the oestrous cycle and early pregnancy. In AP, we also examined colocalisation of visfatin with pituitary tropic hormones. Moreover, we aimed to evaluate the in vitro effects of GnRH, FSH, LH, and insulin on visfatin protein concentration and secretion in AP cells during the cycle. The study showed that visfatin is present in all types of porcine pituitary endocrine cells and its expression is reliant on stage of the cycle or pregnancy. GnRH, FSH, LH and insulin stimulated visfatin secretion by AP cells on days 17 to 19 of the cycle, while on days 2 to 3 visfatin release was enhanced only by LH. Summarising, visfatin is locally produced in the pituitary in a way dependent on hormonal milieu typical for reproductive status of pigs. Further research is required to clarify the role of visfatin in the pituitary gland.
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Affiliation(s)
- Karolina Szymanska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Ewa Zaobidna
- Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Edyta Rytelewska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Ewa Mlyczynska
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa 9, 30-387, Krakow, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University in Krakow, Lojasiewicza 11, 30-348, Krakow, Poland
| | - Patrycja Kurowska
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa 9, 30-387, Krakow, Poland
| | - Kamil Dobrzyn
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, 10-719, Olsztyn, Poland
| | - Marta Kiezun
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Barbara Kaminska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Nina Smolinska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Agnieszka Rak
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa 9, 30-387, Krakow, Poland
| | - Tadeusz Kaminski
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland.
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5
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Kelley DB. Convergent and divergent neural circuit architectures that support acoustic communication. Front Neural Circuits 2022; 16:976789. [PMID: 36466364 PMCID: PMC9712726 DOI: 10.3389/fncir.2022.976789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 10/19/2022] [Indexed: 11/18/2022] Open
Abstract
Vocal communication is used across extant vertebrates, is evolutionarily ancient, and been maintained, in many lineages. Here I review the neural circuit architectures that support intraspecific acoustic signaling in representative anuran, mammalian and avian species as well as two invertebrates, fruit flies and Hawaiian crickets. I focus on hindbrain motor control motifs and their ties to respiratory circuits, expression of receptors for gonadal steroids in motor, sensory, and limbic neurons as well as divergent modalities that evoke vocal responses. Hindbrain and limbic participants in acoustic communication are highly conserved, while forebrain participants have diverged between anurans and mammals, as well as songbirds and rodents. I discuss the roles of natural and sexual selection in driving speciation, as well as exaptation of circuit elements with ancestral roles in respiration, for producing sounds and driving rhythmic vocal features. Recent technical advances in whole brain fMRI across species will enable real time imaging of acoustic signaling partners, tying auditory perception to vocal production.
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6
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Zhang WS, Farmer EJ, Muhanzi D, Trudeau VL. Petroleum-derived naphthenic acids disrupt hormone-dependent sexual behaviours in male Western clawed frogs. CONSERVATION PHYSIOLOGY 2022; 10:coac030. [PMID: 35602560 PMCID: PMC9115893 DOI: 10.1093/conphys/coac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 03/15/2022] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
Naphthenic acids (NAs), the carboxylic acids found in petroleum, are of emerging concern as they contaminate coastlines after oil spills, leech into freshwater ecosystems of oil sands areas and have wide industrial applications. They are acutely toxic in fish and tadpoles and may be endocrine disruptors at sublethal levels. We characterized androgen-dependent courtship behaviours and their disruption by NAs in male Western clawed frogs, Silurana tropicalis. Courtship primarily consists of males producing low trills and achieving amplexus, a mating position where a male clasps a female. Adult males were exposed for 5 days to 20 mg/l NA and injected with human chorionic gonadotropin to induce calling. The duration of calling activity was significantly reduced by NA exposure. Other acoustic parameters such as dominant frequency, click rate and trill length were not affected. Vocalization and amplexus were both inhibited after NA exposure and restored after 2 weeks of recovery in clean water. To determine possible disruption at the level of the testes, the effects of NA exposure on gene expression of key players in steroidogenesis was determined. Exposure to NAs decreased srd5a on average by ~ 25%. The enzyme 5α-reductase, encoded by srd5a, converts testosterone to its more bioactive form 5α-dihydrotestosterone (DHT), so NAs may be affecting this steroidogenic step. However, the observed upregulation of lhr, star and cyp17a1 suggests that NA-exposed males may be attempting to counteract the reduced potential to produce DHT. Yet, these NA-exposed frogs have dramatically reduced calling duration, so the observed upregulation of star and cyp17a1 is decoupled from the vocalizations. Calling duration and the ability of males to amplex females is reversibly disrupted by NA exposure, implying that environmental reduction and removal of NAs may help improve habitability of contaminated ecosystems.
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Affiliation(s)
- Wo Su Zhang
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | | | - Daniella Muhanzi
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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7
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Barkan CL, Leininger EC, Zornik E. Everything in modulation: neuromodulators as keys to understanding communication dynamics. Integr Comp Biol 2021; 61:854-866. [PMID: 34038510 DOI: 10.1093/icb/icab102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Across the animal kingdom, the ability to produce communication signals appropriate to social encounters is essential, but how these behaviors are selected and adjusted in a context-dependent manner is poorly understood. This question can be addressed on many levels, including sensory processing by peripheral organs and the CNS, sensorimotor integration in decision-making brain regions, and motor circuit activation and modulation. Because neuromodulator systems act at each of these levels, they are a useful lens through which to explore the mechanisms underlying complex patterns of communication. It has been clear for decades that understanding the logic of input-output decision making by the nervous system requires far more than simply identifying the connections linking sensory organs to motor circuits; this is due in part to the fact that neuromodulators can promote distinct and temporally dynamic responses to similar signals. We focus on the vocal circuit dynamics of Xenopus frogs, and describe complementary examples from diverse vertebrate communication systems. While much remains to be discovered about how neuromodulators direct flexibility in communication behaviors, these examples illustrate that several neuromodulators can act upon the same circuit at multiple levels of control, and that the functional consequence of neuromodulation can depend on species-specific factors as well as dynamic organismal characteristics like internal state.
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Affiliation(s)
| | | | - Erik Zornik
- Reed College, Biology Department, Portland, OR
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8
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Smith SM, Eigerman AR, LeCure KM, Kironde E, Privett-Mendoza AG, Fuxjager MJ, Preininger D, Mangiamele LA. Androgen Receptor Modulates Multimodal Displays in the Bornean Rock Frog (Staurois parvus). Integr Comp Biol 2021; 61:221-230. [PMID: 34009301 DOI: 10.1093/icb/icab042] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Multimodal communication is common in the animal kingdom. It occurs when animals display by stimulating two or more receiver sensory systems, and often arises when selection favors multiple ways to send messages to conspecifics. Mechanisms of multimodal display behavior are poorly understood, particularly with respect to how animals coordinate the production of different signals. One important question is whether all components in a multimodal display share an underlying physiological basis, or whether different components are regulated independently. We investigated the influence of androgen receptors (ARs) on the production of both visual and vocal signal components in the multimodal display repertoire of the Bornean rock frog (Staurois parvus). To assess the role of AR in signal production, we treated reproductively active adult males with the antiandrogen flutamide (FLUT) and measured the performance of each component signal in the multimodal display. Our results show that blocking AR inhibited the production of multiple visual signals, including a conspicuous visual signal known as the "foot flag," which is produced by rotating the hind limb above the body. However, FLUT treatment caused no measurable change in vocal signaling behavior, or in the frequency or fine temporal properties of males' calls. Our study, therefore, suggests that activation of AR is not a physiological prerequisite to the coordination of multiple signals, in that it either does not regulate all signaling behaviors in a male's display repertoire or it does so only in a context-dependent manner.
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Affiliation(s)
- Sarah M Smith
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
| | - Amelia R Eigerman
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
| | - Kerry M LeCure
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
| | - Eseza Kironde
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
| | | | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Doris Preininger
- Department of Evolutionary Biology, University of Vienna, Vienna, Austria.,Vienna Zoo, Vienna, Austria
| | - Lisa A Mangiamele
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA
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9
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Mey M, Bhatta S, Casadesus G. Luteinizing hormone and the aging brain. VITAMINS AND HORMONES 2021; 115:89-104. [PMID: 33706966 PMCID: PMC9853463 DOI: 10.1016/bs.vh.2020.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Fluctuations in luteinizing hormone (LH) release contribute to the development and maintenance of the reproductive system and become dysregulated during aging. Of note, increasing evidence supports extra-gonadal roles for LH within the CNS, particularly as it relates to cognition and plasticity in aging and age-related degenerative diseases such as Alzheimer's disease (AD). However, despite increasing evidence that supports a link between this hormone and CNS function, the mechanisms underlying LH action within the brain and how they influence cognition and plasticity during the lifespan is poorly understood and, in fact, often in conflict. This chapter aims to provide an up-to-date review of the literature addressing the role of LH signaling in the context of CNS aging and disease and put forward a unifying hypothesis that may explain currently conflicting theories regarding the role of LHCGR signaling in CNS function and dysfunction in aging and disease.
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Affiliation(s)
- Megan Mey
- Department of Biomedical Science, Kent State University, Cunningham Hall, Kent, OH, United States
| | - Sabina Bhatta
- Department of Biomedical Science, Kent State University, Cunningham Hall, Kent, OH, United States
| | - Gemma Casadesus
- Department of Biological Science, School of Arts and Sciences, Kent State University, Cunningham Hall, Kent, OH, United States,Corresponding author: ;
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10
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Generation, Coordination, and Evolution of Neural Circuits for Vocal Communication. J Neurosci 2020; 40:22-36. [PMID: 31896561 DOI: 10.1523/jneurosci.0736-19.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 02/07/2023] Open
Abstract
In many species, vocal communication is essential for coordinating social behaviors including courtship, mating, parenting, rivalry, and alarm signaling. Effective communication requires accurate production, detection, and classification of signals, as well as selection of socially appropriate responses. Understanding how signals are generated and how acoustic signals are perceived is key to understanding the neurobiology of social behaviors. Here we review our long-standing research program focused on Xenopus, a frog genus which has provided valuable insights into the mechanisms and evolution of vertebrate social behaviors. In Xenopus laevis, vocal signals differ between the sexes, through development, and across the genus, reflecting evolutionary divergence in sensory and motor circuits that can be interrogated mechanistically. Using two ex vivo preparations, the isolated brain and vocal organ, we have identified essential components of the vocal production system: the sexually differentiated larynx at the periphery, and the hindbrain vocal central pattern generator (CPG) centrally, that produce sex- and species-characteristic sound pulse frequencies and temporal patterns, respectively. Within the hindbrain, we have described how intrinsic membrane properties of neurons in the vocal CPG generate species-specific vocal patterns, how vocal nuclei are connected to generate vocal patterns, as well as the roles of neurotransmitters and neuromodulators in activating the circuit. For sensorimotor integration, we identified a key forebrain node that links auditory and vocal production circuits to match socially appropriate vocal responses to acoustic features of male and female calls. The availability of a well supported phylogeny as well as reference genomes from several species now support analysis of the genetic architecture and the evolutionary divergence of neural circuits for vocal communication. Xenopus thus provides a vertebrate model in which to study vocal communication at many levels, from physiology, to behavior, and from development to evolution. As one of the most comprehensively studied phylogenetic groups within vertebrate vocal communication systems, Xenopus provides insights that can inform social communication across phyla.
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11
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Leslie CE, Rosencrans RF, Walkowski W, Gordon WC, Bazan NG, Ryan MJ, Farris HE. Reproductive State Modulates Retinal Sensitivity to Light in Female Túngara Frogs. Front Behav Neurosci 2020; 13:293. [PMID: 32076402 PMCID: PMC6985269 DOI: 10.3389/fnbeh.2019.00293] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/23/2019] [Indexed: 12/31/2022] Open
Abstract
Visual cues are often a vital part of animal communication and courtship. While a plethora of studies have focused on the role that hormones play in acoustic communication of anurans, relatively few have explored hormonal modulation of vision in these animals. Much of what we do know comes from behavioral studies, which show that a frog’s hormonal state can significantly affect both its visual behavior and mating decisions. However, to fully understand how frogs use visual cues to make these mating decisions, we must first understand how their visual system processes these cues, and how hormones affect these processes. To do this, we performed electroretinograms (ERGs) to measure retinal sensitivity of túngara frogs (Physalaemus pustulosus), a neotropical species whose mating behavior includes previously described visual cues. To determine the effect of hormonal state on visual sensitivity, ERGs were recorded under scotopic and photopic conditions in frogs that were either non-reproductive or hormone-treated with human chorionic gonadotropin (hCG) prior to testing. Additionally, measurements of optical anatomy determined how túngara frog eye and retina morphology related to physiological sensitivity. As expected, we found that both sexes display higher visual sensitivity under scotopic conditions compared to photopic conditions. However, hormone injections significantly increased retinal sensitivity of females under scotopic conditions. These results support the hypothesis that hormonal modulation of neural mechanisms, such as those mediating visually guided reproductive behavior in this species, include modulation of the receptor organ: the retina. Thus, our data serve as a starting point for elucidating the mechanism of hormonal modulation of visual sensitivity.
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Affiliation(s)
- Caitlin E Leslie
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, United States
| | - Robert F Rosencrans
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, LA, United States
| | - Whitney Walkowski
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, LA, United States.,Department of Cell Biology and Anatomy, Louisiana State University School of Medicine, New Orleans, LA, United States
| | - William C Gordon
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, LA, United States.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, LA, United States
| | - Nicolas G Bazan
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, LA, United States.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, LA, United States
| | - Michael J Ryan
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, United States.,Smithsonian Tropical Research Institute, Balboa, Panama
| | - Hamilton E Farris
- Neuroscience Center, Louisiana State University School of Medicine, New Orleans, LA, United States.,Department of Cell Biology and Anatomy, Louisiana State University School of Medicine, New Orleans, LA, United States.,Department of Otorhinolaryngology, Louisiana State University School of Medicine, New Orleans, LA, United States
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12
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Burow S, Mizrahi N, Maugars G, von Krogh K, Nourizadeh-Lillabadi R, Hollander-Cohen L, Shpilman M, Atre I, Weltzien FA, Levavi-Sivan B. Characterization of gonadotropin receptors Fshr and Lhr in Japanese medaka, Oryzias latipes. Gen Comp Endocrinol 2020; 285:113276. [PMID: 31536722 DOI: 10.1016/j.ygcen.2019.113276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 09/14/2019] [Accepted: 09/14/2019] [Indexed: 10/26/2022]
Abstract
Reproduction in vertebrates is controlled by the brain-pituitary-gonad axis, where the two gonadotropins follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) play vital parts by activating their cognate receptors in the gonads. The main purpose of this work was to study intra- and interspecies ligand promiscuity of teleost gonadotropin receptors, since teleost receptor specificity is unclear, in contrast to mammalian receptors. Receptor activation was investigated by transfecting COS-7 cells with either Fsh receptor (mdFshr, tiFshr) or Lh receptor (mdLhr, tiLhr), and tested for activation by recombinant homologous and heterologous ligands (mdFshβα, mdLhβα, tiFshβα, tiLhβα) from two representative fish orders, Japanese medaka (Oryzias latipes, Beloniformes) and Nile tilapia (Oreochromis niloticus, Cichliformes). Results showed that each gonadotropin preferentially activates its own cognate receptor. Cross-reactivity was detected to some extent as mdFshβα was able to activate the mdLhr, and mdLhβα the mdFshr. Medaka pituitary extract (MPE) stimulated CRE-LUC activity in COS-7 cells expressing mdlhr, but could not stimulate cells expressing mdfshr. Recombinant tiLhβα, tiFshβα and tilapia pituitary extract (TPE) could activate the mdLhr, suggesting cross-species reactivity for mdLhr. Cross-species reactivity was also detected for mdFshr due to activation by tiFshβα, tiLhβα, and TPE, as well as for tiFshr and tiLhr due to stimulation by mdFshβα, mdLhβα, and MPE. Tissue distribution analysis of gene expression revealed that medaka receptors, fshr and lhr, are highly expressed in both ovary and testis. High expression levels were found for lhr also in brain, while fshr was expressed at low levels. Both fshr and lhr mRNA levels increased significantly during testis development. Amino acid sequence alignment and three-dimensional modelling of ligands and receptors highlighted conserved beta sheet domains of both Fsh and Lh between Japanese medaka and Nile tilapia. It also showed a higher structural homology and similarity of transmembrane regions of Lhr between both species, in contrast to Fshr, possibly related to the substitution of the conserved cysteine residue in the transmembrane domain 6 in medaka Fshr with glycine. Taken together, this is the first characterization of medaka Fshr and Lhr using homologous ligands, enabling to better understand teleost hormone-receptor interactions and specificities. The data suggest partial ligand promiscuity and cross-species reactivity between gonadotropins and their receptors in medaka and tilapia.
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Affiliation(s)
- Susann Burow
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Naama Mizrahi
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot 76100, Israel
| | - Gersende Maugars
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Kristine von Krogh
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Rasoul Nourizadeh-Lillabadi
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Lian Hollander-Cohen
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot 76100, Israel
| | - Michal Shpilman
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot 76100, Israel
| | - Ishwar Atre
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot 76100, Israel
| | - Finn-Arne Weltzien
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 0454 Oslo, Norway.
| | - Berta Levavi-Sivan
- Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot 76100, Israel.
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Jahanshahi M, Saeidi M, Nikmahzar E, Babakordi F, Bahlakeh G. Effects of hCG on reduced numbers of hCG receptors in the prefrontal cortex and cerebellum of rat models of Alzheimer's disease. Biotech Histochem 2019; 94:360-365. [PMID: 30760053 DOI: 10.1080/10520295.2019.1571228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Age-associated changes in the levels of luteinizing hormone and human chorionic gonadotropin (hCG) are potential risk factors for Alzheimer's disease (AD); hCG concentration is related to the incidence of AD. The highest density of hCG receptors is in zones of the brain that are vulnerable to AD and streptozotocin (STZ) can decrease the density of this receptor. We investigated the effects of different doses of hCG on hCG receptor density in the prefrontal cortex and cerebellum in a rat model of STZ-induced AD. AD was induced by intracerebroventricular injection of 3 mg/kg STZ. The resulting AD rats were treated for 3 days with 50, 100 or 200 IU/200 μl hCG, or with saline as a control. Sections of prefrontal cortex and cerebellum were stained immunohistochemically and hCG receptor-immunoreactive (ir) neurons were counted. STZ injected into the lateral ventricles of rat brains reduced the density of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. hCG administration resulted in a significant dose-dependent increase in the number of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. The maximum increase in the number of receptors occurred following the 200 IU dose of hCG. Administration of hCG ameliorated the lowered density of hCG receptor-ir neurons in the cerebellum and prefrontal cortex in STZ-induced AD rats.
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Affiliation(s)
- M Jahanshahi
- a Neuroscience Research Center, Golestan University of Medical Sciences , Gorgan , Iran
| | - M Saeidi
- b Stem Cell Research Center, Golestan University of Medical Sciences , Gorgan , Iran
| | - E Nikmahzar
- a Neuroscience Research Center, Golestan University of Medical Sciences , Gorgan , Iran
| | - F Babakordi
- a Neuroscience Research Center, Golestan University of Medical Sciences , Gorgan , Iran
| | - G Bahlakeh
- a Neuroscience Research Center, Golestan University of Medical Sciences , Gorgan , Iran
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Blair JA, Bhatta S, Casadesus G. CNS luteinizing hormone receptor activation rescues ovariectomy-related loss of spatial memory and neuronal plasticity. Neurobiol Aging 2019; 78:111-120. [PMID: 30925299 DOI: 10.1016/j.neurobiolaging.2019.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 10/27/2022]
Abstract
Ovariectomy (OVX), a menopause model, leads to cognition and neuronal plasticity deficits that are rescued by estrogen administration or downregulation of pituitary luteinizing hormone (LH). LH is present in the brain. However, whether LH levels differ across brain regions, change across reproductive stages, or whether brain-specific LHR signaling play a role in OVX-related cognitive and neuroplasticity losses is completely unknown. To address this, we measured brain LH in cycling and OVX C57Bl/6 across brain regions and determined whether OVX-related functional and plasticity deficits could be rescued by intracerebroventricular administration of the LHR agonist (hCG). Here, we show that while pituitary LH is increased in OVX, brain LH is decreased, primarily in spatial memory and navigation areas. Furthermore, intracerebroventricular hCG delivery after OVX rescued dendritic spine density and spatial memory. In vitro, we show that hCG increased neurite outgrowth in primary hippocampal neurons in a receptor-specific manner. Taken together, our data suggest that loss of brain LH signaling is involved in cognitive and plasticity losses associated with OVX and loss of ovarian hormones.
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Affiliation(s)
- Jeffrey A Blair
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Sabina Bhatta
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Gemma Casadesus
- Department of Biological Sciences, Kent State University, Kent, OH, USA.
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Bhatta S, Blair JA, Casadesus G. Luteinizing Hormone Involvement in Aging Female Cognition: Not All Is Estrogen Loss. Front Endocrinol (Lausanne) 2018; 9:544. [PMID: 30319538 PMCID: PMC6165885 DOI: 10.3389/fendo.2018.00544] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/28/2018] [Indexed: 01/29/2023] Open
Abstract
Pervasive age-related dysfunction in hypothalamic-pituitary-gonadal (HPG) axis is associated with cognitive impairments in aging as well as pathogenesis of age-related neurodegenerative diseases such as the Alzheimer's disease (AD). As a major regulator of the HPG axis, the steroid hormone estrogen has been widely studied for its role in regulation of memory. Although estrogen modulates both cognition as well as cognition associated morphological components in a healthy state, the benefits of estrogen replacement therapy on cognition and disease seem to diminish with advancing age. Emerging data suggests an important role for luteinizing hormone (LH) in CNS function, which is another component of the HPG axis that becomes dysregulated during aging, particularly in menopause. The goal of this review is to highlight the current existing literature on LH and provide new insights on possible mechanisms of its action.
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Affiliation(s)
- Sabina Bhatta
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Jeffrey A. Blair
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Gemma Casadesus
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
- Department of Biological Sciences, Kent State University, Kent, OH, United States
- *Correspondence: Gemma Casadesus
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Pandey SP, Tsutsui K, Mohanty B. Endocrine disrupting pesticides impair the neuroendocrine regulation of reproductive behaviors and secondary sexual characters of red munia (Amandava amandava). Physiol Behav 2017; 173:15-22. [DOI: 10.1016/j.physbeh.2017.01.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 12/07/2016] [Accepted: 01/18/2017] [Indexed: 11/26/2022]
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18
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Abstract
Multidirectional interactions among the immune, endocrine, and nervous systems have been demonstrated in humans and non-human animal models for many decades by the biomedical community, but ecological and evolutionary perspectives are lacking. Neuroendocrine-immune interactions can be conceptualized using a series of feedback loops, which culminate into distinct neuroendocrine-immune phenotypes. Behavior can exert profound influences on these phenotypes, which can in turn reciprocally modulate behavior. For example, the behavioral aspects of reproduction, including courtship, aggression, mate selection and parental behaviors can impinge upon neuroendocrine-immune interactions. One classic example is the immunocompetence handicap hypothesis (ICHH), which proposes that steroid hormones act as mediators of traits important for female choice while suppressing the immune system. Reciprocally, neuroendocrine-immune pathways can promote the development of altered behavioral states, such as sickness behavior. Understanding the energetic signals that mediate neuroendocrine-immune crosstalk is an active area of research. Although the field of psychoneuroimmunology (PNI) has begun to explore this crosstalk from a biomedical standpoint, the neuroendocrine-immune-behavior nexus has been relatively underappreciated in comparative species. The field of ecoimmunology, while traditionally emphasizing the study of non-model systems from an ecological evolutionary perspective, often under natural conditions, has focused less on the physiological mechanisms underlying behavioral responses. This review summarizes neuroendocrine-immune interactions using a comparative framework to understand the ecological and evolutionary forces that shape these complex physiological interactions.
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Affiliation(s)
- Noah T Ashley
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA.
| | - Gregory E Demas
- Department of Biology, Center for the Integrative Study of Animal Behavior - Program in Neuroscience, Indiana University, Bloomington, IN 47405, USA
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Blair JA, Palm R, Chang J, McGee H, Zhu X, Wang X, Casadesus G. Luteinizing hormone downregulation but not estrogen replacement improves ovariectomy-associated cognition and spine density loss independently of treatment onset timing. Horm Behav 2016; 78:60-6. [PMID: 26497249 PMCID: PMC4718885 DOI: 10.1016/j.yhbeh.2015.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 10/12/2015] [Accepted: 10/20/2015] [Indexed: 12/31/2022]
Abstract
Age-related changes in reproductive hormone levels are a well-known risk factor for the development of cognitive dysfunction and dementia in women. We and others have shown an important contribution of gonadotropins in this process. Lowering serum gonadotropin levels is able to rescue cognitive function in Alzheimer's disease and menopause models, but whether this is time-dependent and the exact mechanism through which gonadotropins regulate cognitive function is unknown. We show that pharmacologically lowering serum levels of luteinizing hormone lead to cognitive improvement immediately after ovariectomy and with a 4month interval after ovariectomy, when the benefits of 17β-estradiol are known to disappear in rodents. Importantly, we show that these improvements are associated with spine density changes at both time points. These findings suggest a role of luteinizing hormone in learning and memory and neuroplasticity processes as well as provide an alternative therapeutic strategy of menopause associated cognitive loss.
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Affiliation(s)
- Jeffrey A Blair
- School of Biomedical Sciences, Kent State University, Kent, OH, United States; Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Russell Palm
- College of Medicine and Life Sciences, University of Toledo, Toledo, OH, United States
| | - Jaewon Chang
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Henry McGee
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH, United States
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, United States
| | - Gemma Casadesus
- Department of Biological Sciences, Kent State University, Kent, OH, United States.
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Miranda RA, Searcy BT, Propper CR. Arginine vasotocin induces calling behavior with a female social stimulus and interacts with gonadotropins to affect sexual behaviors in male Xenopus tropicalis. Physiol Behav 2015; 151:72-80. [DOI: 10.1016/j.physbeh.2015.06.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 06/18/2015] [Accepted: 06/23/2015] [Indexed: 11/29/2022]
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Blair JA, Bhatta S, McGee H, Casadesus G. Luteinizing hormone: Evidence for direct action in the CNS. Horm Behav 2015; 76:57-62. [PMID: 26172857 PMCID: PMC4741372 DOI: 10.1016/j.yhbeh.2015.06.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 01/09/2023]
Abstract
This article is part of a Special Issue "SBN 2014". Hormonal dysfunction due to aging, especially during menopause, plays a substantial role in cognitive decline as well as the progression and development of neurodegenerative diseases. The hypothalamic-pituitary-gonadal (HPG) axis has long been implicated in changes in behavior and neuronal morphology. Most notably, estrogens have proven beneficial in the healthy brain through a host of different mechanisms. Recently, luteinizing hormone (LH) has emerged as a candidate for further investigation for its role in the CNS. The basis of this is that both LH and the LH receptor are expressed in the brain, and serum levels of LH correlate with cognitive deficits and Alzheimer's disease (AD) incidence. The study of LH in cognition and AD primarily focuses on evaluating the effects of downregulation of this peptide. This literature has shown that decreasing peripheral LH, through a variety of pharmacological interventions, reduces cognitive deficits in ovariectomy and AD models. However, few studies have researched the direct actions of LH on neurons and glial cells. Here we summarize the role of luteinizing hormone in modulating cognition, and we propose a mechanism that underlies a role for brain LH in this process.
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Affiliation(s)
- Jeffrey A Blair
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Sabina Bhatta
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Henry McGee
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Gemma Casadesus
- Department of Biological Sciences, Kent State University, Kent, OH, USA.
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Chakraborty M, Burmeister SS. Effects of estradiol on neural responses to social signals in female túngara frogs. ACTA ACUST UNITED AC 2015; 218:3671-7. [PMID: 26449971 DOI: 10.1242/jeb.127738] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 09/21/2015] [Indexed: 11/20/2022]
Abstract
Estradiol plays an important role in mediating changes in female sexual behavior across reproductive cycles. In the túngara frog [Physalaemus (=Engystomops) pustulosus], the relationship between gonadal activity and female sexual behavior, as expressed by phonotaxis, is mediated primarily by estradiol. Estradiol receptors are expressed in auditory and motivational brain areas and the hormone could serve as an important modulator of neural responses to conspecific calls. To better understand how estradiol modifies neural responses to conspecific social signals, we manipulated estradiol levels and measured expression of the immediate early gene egr-1 in the auditory midbrain, thalamus and limbic forebrain in response to conspecific or heterospecific calls. We found that estradiol and conspecific calls increased egr-1 expression in the auditory midbrain and limbic forebrain, but in the thalamus, only conspecific calls were effective. In the preoptic area, estradiol enhanced the effect of the conspecific call on egr-1 expression, suggesting that the preoptic area could act as a hormonal gatekeeper to phonotaxis. Overall, the results suggest that estradiol has broad influences on the neural circuit involved in female reproduction, particularly those implicated in phonotaxis.
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Affiliation(s)
- Mukta Chakraborty
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Sabrina S Burmeister
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA
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Maugars G, Dufour S. Demonstration of the Coexistence of Duplicated LH Receptors in Teleosts, and Their Origin in Ancestral Actinopterygians. PLoS One 2015; 10:e0135184. [PMID: 26271038 PMCID: PMC4536197 DOI: 10.1371/journal.pone.0135184] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/18/2015] [Indexed: 11/18/2022] Open
Abstract
Pituitary gonadotropins, FSH and LH, control gonad activity in vertebrates, via binding to their respective receptors, FSHR and LHR, members of GPCR superfamily. Until recently, it was accepted that gnathostomes possess a single FSHR and a single LHR, encoded by fshr and lhcgr genes. We reinvestigated this question, focusing on vertebrate species of key-phylogenetical positions. Genome analyses supported the presence of a single fshr and a single lhcgr in chondrichthyans, and in sarcopterygians including mammals, birds, amphibians and coelacanth. In contrast, we identified a single fshr but two lhgcr in basal teleosts, the eels. We further showed the coexistence of duplicated lhgcr in other actinopterygians, including a non-teleost, the gar, and other teleosts, e.g. Mexican tetra, platyfish, or tilapia. Phylogeny and synteny analyses supported the existence in actinopterygians of two lhgcr paralogs (lhgcr1/ lhgcr2), which do not result from the teleost-specific whole-genome duplication (3R), but likely from a local gene duplication that occurred early in the actinopterygian lineage. Due to gene losses, there was no impact of 3R on the number of gonadotropin receptors in extant teleosts. Additional gene losses during teleost radiation, led to a single lhgcr (lhgcr1 or lhgcr2) in some species, e.g. medaka and zebrafish. Sequence comparison highlighted divergences in the extracellular and intracellular domains of the duplicated lhgcr, suggesting differential properties such as ligand binding and activation mechanisms. Comparison of tissue distribution in the European eel, revealed that fshr and both lhgcr transcripts are expressed in the ovary and testis, but are differentially expressed in non-gonadal tissues such as brain or eye. Differences in structure-activity relationships and tissue expression may have contributed as selective drives in the conservation of the duplicated lhgcr. This study revises the evolutionary scenario and nomenclature of gonadotropin receptors, and opens new research avenues on the roles of duplicated LHR in actinopterygians.
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Affiliation(s)
- Gersende Maugars
- Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208-IRD 207-UPMC-UCBN, Paris, France
| | - Sylvie Dufour
- Muséum National d'Histoire Naturelle, Sorbonne Universités, Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208-IRD 207-UPMC-UCBN, Paris, France
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25
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Blair JA, McGee H, Bhatta S, Palm R, Casadesus G. Hypothalamic-pituitary-gonadal axis involvement in learning and memory and Alzheimer's disease: more than "just" estrogen. Front Endocrinol (Lausanne) 2015; 6:45. [PMID: 25859241 PMCID: PMC4373369 DOI: 10.3389/fendo.2015.00045] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/12/2015] [Indexed: 11/25/2022] Open
Abstract
Accumulating studies affirm the effects of age-related endocrine dysfunction on cognitive decline and increasing risk of neurodegenerative diseases. It is well known that estrogens can be protective for cognitive function, and more recently androgens and luteinizing hormone have also been shown to modulate learning and memory. Understanding the mechanisms underlying hypothalamic-pituitary-gonadal axis-associated cognitive dysfunction is crucial for therapeutic advancement. Here, we emphasize that reproductive hormones are influential in maintaining neuronal health and enhancing signaling cascades that lead to cognitive impairment. We summarize and critically evaluate age-related changes in the endocrine system, their implications in the development of Alzheimer's disease, and the therapeutic potential of endocrine modulation in the prevention of age-related cognitive decline.
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Affiliation(s)
- Jeffrey A. Blair
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Henry McGee
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Sabina Bhatta
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Russell Palm
- University of Toledo School of Medicine, Toledo, OH, USA
| | - Gemma Casadesus
- Department of Biological Sciences, Kent State University, Kent, OH, USA
- *Correspondence: Gemma Casadesus, Department of Biological Sciences, Kent State University, 256 Cunningham Hall, Kent, OH 44242, USA e-mail:
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26
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Neuromolecular responses to social challenge: common mechanisms across mouse, stickleback fish, and honey bee. Proc Natl Acad Sci U S A 2014; 111:17929-34. [PMID: 25453090 DOI: 10.1073/pnas.1420369111] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Certain complex phenotypes appear repeatedly across diverse species due to processes of evolutionary conservation and convergence. In some contexts like developmental body patterning, there is increased appreciation that common molecular mechanisms underlie common phenotypes; these molecular mechanisms include highly conserved genes and networks that may be modified by lineage-specific mutations. However, the existence of deeply conserved mechanisms for social behaviors has not yet been demonstrated. We used a comparative genomics approach to determine whether shared neuromolecular mechanisms could underlie behavioral response to territory intrusion across species spanning a broad phylogenetic range: house mouse (Mus musculus), stickleback fish (Gasterosteus aculeatus), and honey bee (Apis mellifera). Territory intrusion modulated similar brain functional processes in each species, including those associated with hormone-mediated signal transduction and neurodevelopment. Changes in chromosome organization and energy metabolism appear to be core, conserved processes involved in the response to territory intrusion. We also found that several homologous transcription factors that are typically associated with neural development were modulated across all three species, suggesting that shared neuronal effects may involve transcriptional cascades of evolutionarily conserved genes. Furthermore, immunohistochemical analyses of a subset of these transcription factors in mouse again implicated modulation of energy metabolism in the behavioral response. These results provide support for conserved genetic "toolkits" that are used in independent evolutions of the response to social challenge in diverse taxa.
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Sweeney LB, Kelley DB. Harnessing vocal patterns for social communication. Curr Opin Neurobiol 2014; 28:34-41. [PMID: 24995669 PMCID: PMC4177452 DOI: 10.1016/j.conb.2014.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/23/2014] [Accepted: 06/04/2014] [Indexed: 12/16/2022]
Abstract
Work on vocal communication, influenced by a drive to understand the evolution of language, has focused on auditory processing and forebrain control of learned vocalizations. The actual hindbrain neural mechanisms used to create communication signals are understudied, in part because of the difficulty of experimental studies in species that rely on respiration for vocalization. In these experimental systems-including those that embody vocal learning-vocal behaviors have rhythmic qualities. Recent studies using molecular markers and 'fictive' patterns produced by isolated brains are beginning to reveal how hindbrain circuits generate vocal patterns. Insights from central pattern generators for respiration and locomotion are illuminating common neural and developmental mechanisms. Choice of vocal patterns is responsive to socially salient input. Studies of the vertebrate social brain network suggest mechanisms used to integrate socially salient information and produce an appropriate vocal response.
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Affiliation(s)
- Lora B Sweeney
- Molecular Neurobiology Laboratory, Salk Institute, 10010 N Torrey Pines Rd, La Jolla, CA 92037, United States
| | - Darcy B Kelley
- Dept. of Biological Sciences, Columbia University, 1616 Amsterdam Avenue, New York, NY 10027, United States.
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28
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Abstract
Social interaction requires that relevant sensory information is collected, classified, and distributed to the motor areas that initiate an appropriate behavioral response. Vocal exchanges, in particular, depend on linking auditory processing to an appropriate motor expression. Because of its role in integrating sensory information for the purpose of action selection, the amygdala has been implicated in social behavior in many mammalian species. Here, we show that two nuclei of the extended amygdala play essential roles in vocal communication in the African clawed frog, Xenopus laevis. Transport of fluorescent dextran amines identifies the X. laevis central amygdala (CeA) as a target for ascending auditory information from the central thalamic nucleus and as a major afferent to the vocal pattern generator of the hindbrain. In the isolated (ex vivo) brain, electrical stimulation of the CeA, or the neighboring bed nucleus of the stria terminalis (BNST), initiates bouts of fictive calling. In vivo, lesioning the CeA of males disrupts the production of appropriate vocal responses to females and to broadcasts of female calls. Lesioning the BNST in males produces an overall decrease in calling behavior. Together, these results suggest that the anuran CeA evaluates the valence of acoustic cues and initiates socially appropriate vocal responses to communication signals, whereas the BNST plays a role in the initiation of vocalizations.
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Kim JK, Kim IH, Heo JH, Lee JH, Ra NY, Eom J, Jeong SM, Lee HJ, Park D. Arginine Vasotocin (AVT) Triggers Courtship Behavior Without Exposure to External Stimuli and Modulates the Olfactory Response of MaleHynobius leechiiSalamanders. Zoolog Sci 2013; 30:929-37. [DOI: 10.2108/zsj.30.929] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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30
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Heyland A, Plachetzki D, Donelly E, Gunaratne D, Bobkova Y, Jacobson J, Kohn AB, Moroz LL. Distinct expression patterns of glycoprotein hormone subunits in the lophotrochozoan Aplysia: implications for the evolution of neuroendocrine systems in animals. Endocrinology 2012; 153:5440-51. [PMID: 22977258 PMCID: PMC3473217 DOI: 10.1210/en.2012-1677] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glycoprotein hormones (GPHs) comprise a group of signaling molecules critical for major metabolic and reproductive functions. In vertebrates they include chorionic gonadotropin, LH, FSH, and TSH. The active hormones are characterized by heterodimerization between a common α and hormone-specific β subunit, which activate leucine-rich repeat-containing G protein coupled receptors. To date, genes referred to as GPHα2 and GPHβ5 have been the only glycoprotein hormone subunits identified in invertebrates, suggesting that other GPHα and GPHβ subunits diversified during vertebrate evolution. Still the functions of GPHα2 and GPHβ5 remain largely unknown for both vertebrates and invertebrates. To further understand the evolution and putative function of these subunits, we cloned and analyzed phylogenetically two glycoprotein subunits, AcaGPHα and AcaGPHβ, from the sea hare Aplysia californica. Model based three-dimensional predictions of AcaGPHβ confirm the presence of a complete cysteine knot, two hairpin loops, and a long loop. As in the human GPHβ5 subunit the seatbelt structure is absent in AcaGPHβ. We also found that AcaGPHα and AcaGPHβ subunits are expressed in larval stages of Aplysia, and we present a detailed expression map of the subunits in the adult central nervous system using in situ hybridizations. Both subunits are expressed in subpopulations of pleural and buccal mechanosensory neurons, suggesting a neuronal modulatory function of these subunits in Aplysia. Furthermore it supports the model of a relatively diffuse neuroendocrine-like system in molluscs, where specific primary sensory neurons release peptides extrasynaptically (paracrine secretion). This is in contrast to vertebrates and insects, in which releasing and stimulating factor from centralized sensory regions of the central nervous system ultimately regulate hormone release in peripheral glands.
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Affiliation(s)
- Andreas Heyland
- Department of Integrative Biology, University of Guelph, Ontario, Canada.
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31
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Schwendiman AL, Propper CR. A common environmental contaminant affects sexual behavior in the clawed frog, Xenopus tropicalis. Physiol Behav 2012; 106:520-6. [DOI: 10.1016/j.physbeh.2012.03.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 01/19/2012] [Accepted: 03/26/2012] [Indexed: 01/22/2023]
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Kazeto Y, Kohara M, Tosaka R, Gen K, Yokoyama M, Miura C, Miura T, Adachi S, Yamauchi K. Molecular Characterization and Gene Expression of Japanese Eel (Anguilla japonica) Gonadotropin Receptors. Zoolog Sci 2012; 29:204-11. [DOI: 10.2108/zsj.29.204] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
The main component of classical contraceptives, 17α-ethinylestradiol (EE2), has high estrogenic activity even at environmentally relevant concentrations. Although estrogenic endocrine disrupting compounds are assumed to contribute to the worldwide decline of amphibian populations by adverse effects on sexual differentiation, evidence for EE2 affecting amphibian mating behaviour is lacking. In this study, we demonstrate that EE2 exposure at five different concentrations (0.296 ng/L, 2.96 ng/L, 29.64 ng/L, 2.96 µg/L and 296.4 µg/L) can disrupt the mating behavior of adult male Xenopus laevis. EE2 exposure at all concentrations lowered male sexual arousal, indicated by decreased proportions of advertisement calls and increased proportions of the call type rasping, which characterizes a sexually unaroused state of a male. Additionally, EE2 at all tested concentrations affected temporal and spectral parameters of the advertisement calls, respectively. The classical and highly sensitive biomarker vitellogenin, on the other hand, was only induced at concentrations equal or higher than 2.96 µg/L. If kept under control conditions after a 96 h EE2 exposure (2.96 µg/L), alterations of male advertisement calls vanish gradually within 6 weeks and result in a lower sexual attractiveness of EE2 exposed males toward females as demonstrated by female choice experiments. These findings indicate that exposure to environmentally relevant EE2 concentrations can directly disrupt male mate calling behavior of X. laevis and can indirectly affect the mating behavior of females. The results suggest the possibility that EE2 exposure could reduce the reproductive success of EE2 exposed animals and these effects might contribute to the global problem of amphibian decline.
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Affiliation(s)
- Frauke Hoffmann
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
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A neuroendocrine basis for the hierarchical control of frog courtship vocalizations. Front Neuroendocrinol 2011; 32:353-66. [PMID: 21192966 PMCID: PMC3090693 DOI: 10.1016/j.yfrne.2010.12.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 12/21/2010] [Accepted: 12/23/2010] [Indexed: 01/14/2023]
Abstract
Seasonal courtship signals, such as mating calls, are orchestrated by steroid hormones. Sex differences are also sculpted by hormones, typically during brief sensitive periods. The influential organizational-activational hypothesis [50] established the notion of a strong distinction between long-lasting (developmental) and cyclical (adult) effects. While the dichotomy is not always strict [1], experimental paradigms based on this hypothesis have indeed revealed long-lasting hormone actions during development and more transient anatomical, physiological and behavioral effects of hormonal variation in adulthood. Sites of action during both time periods include forebrain and midbrain sensorimotor integration centers, hindbrain and spinal cord motor centers, and muscles. African clawed frog (Xenopus laevis) courtship vocalizations follow the basic organization-activation pattern of hormone-dependence with some exceptions, including expanded steroid-sensitive periods. Two highly-tractable preparations-the isolated larynx and the fictively calling brain-make this model system powerful for dissecting the hierarchical action of hormones. We discuss steroid effects from larynx to forebrain, and introduce new directions of inquiry for which Xenopus vocalizations are especially well-suited.
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Zornik E, Yamaguchi A. Vocal pathway degradation in gonadectomized Xenopus laevis adults. J Neurophysiol 2011; 105:601-14. [PMID: 21148092 PMCID: PMC3059166 DOI: 10.1152/jn.00883.2010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 12/04/2010] [Indexed: 01/26/2023] Open
Abstract
Reproductive behaviors of many vertebrate species are activated in adult males by elevated androgen levels and abolished by castration. Neural and muscular components controlling these behaviors contain numerous hormone-sensitive sites including motor initiation centers (such as the basal ganglia), central pattern generators (CPGs), and muscles; therefore it is difficult to confirm the role of each hormone-activated target using behavioral assays alone. Our goal was to address this issue by determining the site of androgen-induced vocal activation using male Xenopus laevis, a species in which androgen dependence of vocal activation has been previously determined. We compared in vivo calling patterns and functionality of two in vitro preparations-the isolated larynx and an isolated brain from which fictive courtship vocalizations can be evoked--in castrated and control males. The isolated larynx allowed us to test whether castrated males were capable of transducing male-typical nerve signals into vocalizations and the fictively vocalizing brain preparation allowed us to directly examine vocal CPG function separate from the issue of vocal initiation. The results indicate that all three components--vocal initiation, CPG, and larynx--require intact gonads. Vocal production decreased dramatically in castrates and laryngeal contractile properties of castrated males were demasculinized, whereas no changes were observed in control animals. In addition, fictive calls of castrates were degraded compared with those of controls. To our knowledge, this finding represents the first demonstration of gonad-dependent maintenance of a CPG for courtship behavior in adulthood. Because previous studies showed that androgen-replacement can prevent castration-induced vocal impairments, we conclude that degradation of vocal initiation centers, larynx, and CPG function are most likely due to steroid hormone deprivation.
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Affiliation(s)
- Erik Zornik
- Biology Department, Boston University, Boston, Massachusetts, USA.
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36
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Kelley DB, Bass AH. Neurobiology of vocal communication: mechanisms for sensorimotor integration and vocal patterning. Curr Opin Neurobiol 2010; 20:748-53. [PMID: 20829032 DOI: 10.1016/j.conb.2010.08.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 08/10/2010] [Indexed: 01/22/2023]
Abstract
This review will focus on recent developments in the sensorimotor integration of vocal communication. Two broad themes are emphasized: the evolution of vocal production and perception, and the role of social context. Advances include: a proposal for the emergence of vocal patterning during vertebrate evolution, the role of sensory mechanisms such as categorical perception in decoding communication signals, contributions of sensorimotor integration phenomena including mirror neurons and vocal learning, and mechanisms of hormone-dependent plasticity in both auditory and vocal systems. Transcriptional networks activated in humans but not in chimps by the FoxP2 gene suggest molecular mechanisms underlying vocal gestures and the emergence of human language.
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Affiliation(s)
- Darcy B Kelley
- Department of Biological Sciences, MC2432, Columbia University, New York, NY 10025, USA.
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Hoffmann F, Kloas W. An environmentally relevant endocrine-disrupting antiandrogen, vinclozolin, affects calling behavior of male Xenopus laevis. Horm Behav 2010; 58:653-9. [PMID: 20600051 DOI: 10.1016/j.yhbeh.2010.06.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/08/2010] [Accepted: 06/08/2010] [Indexed: 11/22/2022]
Abstract
Vinclozolin (VIN) is an antiandrogenic model substance as well as a common fungicide that can affect the endocrine system of vertebrates. The objective of this study was to investigate how VIN affects mate calling behavior of South African clawed frogs (Xenopus laevis) and whether it is effective at environmentally relevant concentrations. Male X. laevis were injected with human chorionic gonadotropin (hCG) to stimulate their androgen-controlled mate calling behavior and were treated with VIN at concentrations of 10(-6), 10(-8) and 10(-10)M. VIN at 10(-6)M reduced calling activity. Furthermore, the vocalization composition of VIN-treated X. laevis was altered. The call types advertisement calls and chirping are uttered by reproductively active males, whereas the call types growling, ticking, and rasping indicate a sexually unaroused state of a male. VIN at any of the tested concentrations led to a decrease in utterance of calls, which indicate a sexually aroused state of the males, and an increase in relative proportions of calls, indicating a sexually unaroused state of the males. Additionally, the mean duration of clicks and the number of accentuated clicks during the advertisement calls decreased at all concentrations of VIN. No significant differences were observed in any other temporal or spectral calling parameters between the treatments. This study illustrates that exposure to the antiandrogen VIN might result in a reduced reproductive success by altering mate calling behavior of X. laevis. Moreover, it suggests that the behavioral parameters examined in this study can be used as sensitive biomarkers for detecting antiandrogenic endocrine disrupting compounds in amphibians.
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Affiliation(s)
- Frauke Hoffmann
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin, Germany.
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38
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Urbatzka R, Lorenz C, Lutz I, Kloas W. Expression profiles of LHbeta, FSHbeta and their gonadal receptor mRNAs during sexual differentiation of Xenopus laevis tadpoles. Gen Comp Endocrinol 2010; 168:239-44. [PMID: 20171219 DOI: 10.1016/j.ygcen.2010.02.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 02/08/2010] [Accepted: 02/12/2010] [Indexed: 02/04/2023]
Abstract
The gonadotropins, luteinising hormone (LH) and follicle stimulating hormone (FSH), are important hormones regulating reproductive biology in vertebrates, especially the processes of steroidogenesis and gamete maturation. Despite the role of gonadotropins during the reproductive cycle in amphibians is well established, much less is known about the functional maturation of the hypothalamus-pituitary-gonad axis during larval development. Therefore, the present study aimed to analyze the expression profiles of hypophyseal LHbeta and FSHbeta mRNA and of their corresponding gonadal receptors (LH-R, FSH-R) in Xenopus laevis tadpoles during their ontogeny and sexual differentiation. The first significant elevation of LHbeta and FSHbeta mRNA was observed at late premetamorphosis. A clear raise of LHbeta mRNA was present during prometamorphic stages especially in males, while the LH-R only slowly increased during ontogeny with highest levels during metamorphic climax. In contrast, FSHbeta mRNA expression only slightly increased during ontogeny, however in both sexes the FSH-R mRNA was considerably elevated at prometamorphosis and further at metamorphic climax. Our results suggest that LHbeta and LH-R mRNA expression might be involved in initial maturation events of gametes, at least in males, while the gradually increase of FSH-R mRNA coincided with the advancing process of gamete maturation in both sexes. The present study provides for the first time evidence based on expression of gonadotropins and their corresponding gonadal receptors that the hypothalamus-pituitary-gonad axis evolves already at early stages of ontogeny and sexual differentiation in amphibians.
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Affiliation(s)
- R Urbatzka
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, IGB, Mueggelseedamm 301, 12587 Berlin, Germany.
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39
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Affiliation(s)
- John B Wallingford
- Howard Hughes Medical Institute, University of Texas at Austin, Austin, Texas 78712, USA
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40
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Arch VS, Narins PM. Sexual hearing: the influence of sex hormones on acoustic communication in frogs. Hear Res 2009; 252:15-20. [PMID: 19272318 PMCID: PMC2722832 DOI: 10.1016/j.heares.2009.01.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 12/17/2008] [Accepted: 01/12/2009] [Indexed: 01/29/2023]
Abstract
The majority of anuran amphibians (frogs and toads) use acoustic communication to mediate sexual behavior and reproduction. Generally, females find and select their mates using acoustic cues provided by males in the form of conspicuous advertisement calls. In these species, vocal signal production and reception are intimately tied to successful reproduction. Research with anurans has demonstrated that acoustic communication is modulated by reproductive hormones, including gonadal steroids and peptide neuromodulators. Most of these studies have focused on the ways in which hormonal systems influence vocal signal production; however, here we will concentrate on a growing body of literature that examines hormonal modulation of call reception. This literature suggests that reproductive hormones contribute to the coordination of reproductive behaviors between signaler and receiver by modulating sensitivity and spectral filtering of the anuran auditory system. It has become evident that the hormonal systems that influence reproductive behaviors are highly conserved among vertebrate taxa. Thus, studying the endocrine and neuromodulatory bases of acoustic communication in frogs and toads can lead to insights of broader applicability to hormonal modulation of vertebrate sensory physiology and behavior.
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Affiliation(s)
- Victoria S. Arch
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Dr. South Los Angeles, CA 90095-1606, USA
| | - Peter M. Narins
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Dr. South Los Angeles, CA 90095-1606, USA
- Department of Physiological Science, University of California, Los Angeles, 621 Charles E. Young Dr. South Los Angeles, CA 90095-1606, USA
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41
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42
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Chakraborty M, Burmeister SS. Estradiol induces sexual behavior in female túngara frogs. Horm Behav 2009; 55:106-12. [PMID: 18840446 DOI: 10.1016/j.yhbeh.2008.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2008] [Revised: 09/02/2008] [Accepted: 09/02/2008] [Indexed: 02/06/2023]
Abstract
Steroid hormones play an important role in regulating vertebrate sexual behavior. In frogs and toads, injections of exogenous gonadotropins, which stimulate steroid hormone production, are often used to induce reproductive behavior, but steroid hormones alone are not always sufficient. To determine which hormonal conditions promote sexual behavior in female túngara frogs, we assessed the effect of hormone manipulation on the probability of phonotaxis behavior toward conspecific calls in post-reproductive females. We injected females with human chorionic gonadotropin (HCG), estradiol, estradiol plus progesterone, saline, or HCG plus fadrozole (an aromatase blocker) and tested their responses to mating calls. We found that injections of HCG, estradiol, and estradiol plus progesterone all increased phonotaxis behavior, whereas injections of saline or HCG plus fadrozole did not. Since injections of estradiol alone were effective at increasing phonotaxis behavior, we concluded that estradiol is sufficient for the expression of phonotaxis behavior. Next, to determine if estradiol-injected females display the same behavioral preferences as naturally breeding females, we compared mating call preferences of naturally breeding females to those of post-reproductive females injected with estradiol. We found that, when injected with estradiol, females show similar call preferences as naturally breeding females, although they were less likely to respond across multiple phonotaxis tests. Overall, our results suggest that estradiol is sufficient for the expression of sexual responses to mating calls in túngara frogs. To our knowledge, ours is the only study to find that estradiol alone is capable of promoting phonotaxis behavior in a frog.
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Affiliation(s)
- Mukta Chakraborty
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA.
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43
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Schmidt KL, Pradhan DS, Shah AH, Charlier TD, Chin EH, Soma KK. Neurosteroids, immunosteroids, and the Balkanization of endocrinology. Gen Comp Endocrinol 2008; 157:266-74. [PMID: 18486132 DOI: 10.1016/j.ygcen.2008.03.025] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2008] [Revised: 03/14/2008] [Accepted: 03/26/2008] [Indexed: 12/12/2022]
Abstract
Traditionally, the production and regulation of steroid hormones has been viewed as a multi-organ process involving the hypothalamic-pituitary-gonadal (HPG) axis for sex steroids and the hypothalamic-pituitary-adrenal (HPA) axis for glucocorticoids. However, active steroids can also be synthesized locally in target tissues, either from circulating inactive precursors or de novo from cholesterol. Here, we review recent work demonstrating local steroid synthesis, with an emphasis on steroids synthesized in the brain (neurosteroids) and steroids synthesized in the immune system (immunosteroids). Furthermore, recent evidence suggests that other components of the HPG axis (luteinizing hormone and gonadotropin-releasing hormone) and HPA axis (adrenocorticotropic hormone and corticotropin-releasing hormone) are expressed locally in target tissues, potentially providing a mechanism for local regulation of neurosteroid and immunosteroid synthesis. The balance between systemic and local steroid signals depends critically on life history stage, species adaptations, and the costs of systemic signals. During particular life history stages, there can be a shift from systemic to local steroid signals. We propose that the shift to local synthesis and regulation of steroids within target tissues represents a "Balkanization" of the endocrine system, whereby individual tissues and organs may become capable of autonomously synthesizing and modulating local steroid signals, perhaps independently of the HPG and HPA axes.
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Affiliation(s)
- Kim L Schmidt
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada
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44
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Bibliography. Current world literature. Adrenal cortex. Curr Opin Endocrinol Diabetes Obes 2008; 15:284-299. [PMID: 18438178 DOI: 10.1097/med.0b013e3283040e80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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45
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Lynch KS, Wilczynski W. Reproductive hormones modify reception of species-typical communication signals in a female anuran. BRAIN, BEHAVIOR AND EVOLUTION 2007; 71:143-50. [PMID: 18032889 DOI: 10.1159/000111460] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 09/12/2007] [Indexed: 12/14/2022]
Abstract
In many vertebrates, the production and reception of species-typical courtship signals occurs when gonadotropin and gonadal hormone levels are elevated. These hormones may modify sensory processing in the signal receiver in a way that enhances behavioral responses to the signal. We examined this possibility in female túngara frogs (Physalaemus pustulosus) by treating them with either gonadotropin (which elevated estradiol) or saline and exposing them to either mate choruses or silence. Expression of an activity-dependent gene, egr-1, was quantified within two sub-nuclei of the auditory midbrain to investigate whether gonadotropin plus chorus exposure induced greater egr-1 induction than either of these stimuli alone. The laminar nucleus (LN), a sub-nucleus of the torus semicircularis that contains steroid receptors, exhibited elevated egr-1 induction in response to chorus exposure and gonadotropin treatment. Further analysis revealed that neither chorus exposure nor gonadotropin treatment alone elevated egr-1 expression in comparison to baseline levels whereas gonadotropin + chorus exposure did. This suggests that mate signals and hormones together produce an additive effect so that together they induce more egr-1 expression than either alone. Our previously published studies of female túngara frogs reveal that (1) gonadotropin-induced estradiol elevations also increase behavioral responses to male signals, and (2) reception of male signals elevates estradiol levels in the female. Here, we report data that reveal a novel mechanism by which males exploit female sensory processing to increase behavioral responses to their courtship signals.
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Affiliation(s)
- Kathleen S Lynch
- Institute for Neuroscience, University of Texas, Austin, Tex, USA.
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46
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Abstract
The hippocampus has a critical role in certain kinds of spatial memory processes. Hippocampal "place" cells, fire selectively when an animal is in a particular location within the environment. It is thought that this activity underlies a representation of the environment that can be used for memory-based spatial navigation. But how is this representation constructed and how is it "read"? A simple mechanism, based on place field density across an environment, is described that could allow hippocampal representations to be "read" by other brain regions for the purpose of navigation. The possible influence of activity in neighboring brain regions such as the perirhinal cortex, and pre- and para-subiculum on the construction of the hippocampal spatial representation is then discussed.
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Affiliation(s)
- David K Bilkey
- Department of Psychology, University of Otago, 95 Union Street, Dunedin, New Zealand.
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