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Shapouri S, Sharifi A, Folkedal O, Fraser TWK, Vindas MA. Behavioral and neurophysiological effects of buspirone in healthy and depression-like state juvenile salmon. Front Behav Neurosci 2024; 18:1285413. [PMID: 38410095 PMCID: PMC10894974 DOI: 10.3389/fnbeh.2024.1285413] [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: 08/30/2023] [Accepted: 01/11/2024] [Indexed: 02/28/2024] Open
Abstract
A proportion of farmed salmon in seawater show a behaviorally inhibited, growth stunted profile known as a depression-like state (DLS). These DLS fish are characterized by chronically elevated serotonergic signaling and blood plasma cortisol levels and the inability to react further to acute stress, which is suggestive of chronic stress. In this study, we characterize the neuroendocrine profile of growth stunted freshwater parr and confirm that they show a DLS-like neuroendocrine profile with a blunted cortisol response and no serotonergic increase in response to acute stress. Furthermore, we attempted to reverse this DLS-like profile through pharmacological manipulation of the serotonin (5-HT) system with buspirone, an anxiolytic medication that acts as a serotonin receptor agonist (i.e., decreases serotonergic signaling). We found that while buspirone decreases anxiolytic-type behavior in healthy fish, no quantifiable behavioral change was found in DLS-like fish. However, there was a physiological effect of diminished basal serotonergic signaling. This suggests that at the physiological level, buspirone appears to reverse the neuroendocrine DLS profile. With a deeper understanding of what causes DLS profiles and growth stunting in juvenile fish, steps can be taken in terms of husbandry to prevent repeated stressors and the formation of the DLS profile, potentially reducing losses in aquaculture due to chronic stress.
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Affiliation(s)
- Sheyda Shapouri
- Biochemistry and Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, As, Norway
| | - Aziz Sharifi
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Ole Folkedal
- Animal Welfare, Matre Research Station, Institute of Marine Research, Bergen, Norway
| | - Thomas W. K. Fraser
- Reproduction and Developmental Biology, Matre Research Station, Institute of Marine Research, Bergen, Norway
| | - Marco A. Vindas
- Biochemistry and Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, As, Norway
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2
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Natsaridis E, Perdikaris P, Fokos S, Dermon CR. Neuronal and Astroglial Localization of Glucocorticoid Receptor GRα in Adult Zebrafish Brain ( Danio rerio). Brain Sci 2023; 13:861. [PMID: 37371341 DOI: 10.3390/brainsci13060861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Glucocorticoid receptor α (GRα), a ligand-regulated transcription factor, mainly activated by cortisol in humans and fish, mediates neural allostatic and homeostatic functions induced by different types of acute and chronic stress, and systemic inflammation. Zebrafish GRα is suggested to have multiple transcriptional effects essential for normal development and survival, similarly to mammals. While sequence alignments of human, monkey, rat, and mouse GRs have shown many GRα isoforms, we questioned the protein expression profile of GRα in the adult zebrafish (Danio rerio) brain using an alternative model for stress-related neuropsychiatric research, by means of Western blot, immunohistochemistry and double immunofluorescence. Our results identified four main GRα-like immunoreactive bands (95 kDa, 60 kDa, 45 kDa and 35 kDa), with the 95 kDa protein showing highest expression in forebrain compared to midbrain and hindbrain. GRα showed a wide distribution throughout the antero-posterior zebrafish brain axis, with the most prominent labeling within the telencephalon, preoptic, hypothalamus, midbrain, brain stem, central grey, locus coeruleus and cerebellum. Double immunofluorescence revealed that GRα is coexpressed in TH+, β2-AR+ and vGLUT+ neurons, suggesting the potential of GRα influences on adrenergic and glutamatergic transmission. Moreover, GRα was co-localized in midline astroglial cells (GFAP+) within the telencephalon, hypothalamus and hindbrain. Interestingly, GRα expression was evident in the brain regions involved in adaptive stress responses, social behavior, and sensory and motor integration, supporting the evolutionarily conserved features of glucocorticoid receptors in the zebrafish brain.
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Affiliation(s)
- Evangelos Natsaridis
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Rion, 26504 Patras, Greece
| | - Panagiotis Perdikaris
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Rion, 26504 Patras, Greece
| | - Stefanos Fokos
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Rion, 26504 Patras, Greece
| | - Catherine R Dermon
- Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, Rion, 26504 Patras, Greece
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3
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Parker CG, Cheung E. Metabolic control of teleost reproduction by leptin and its complements: Understanding current insights from mammals. Gen Comp Endocrinol 2020; 292:113467. [PMID: 32201232 DOI: 10.1016/j.ygcen.2020.113467] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/05/2020] [Accepted: 03/18/2020] [Indexed: 12/15/2022]
Abstract
Reproduction is expensive. Hence, reproductive physiology is sensitive to an array of endogenous signals that provide information on metabolic and nutritional sufficiency. Although metabolic gating of reproductive function in mammals, as evidenced by studies demonstrating delayed puberty and perturbed fertility, has long been understood to be a function of energy sufficiency, an understanding of the endocrine regulators of this relationship have emerged only within recent decades. Peripheral signals including leptin and cortisol have long been implicated in the physiological integration of metabolism and reproduction. Recent studies have begun to explore possible roles for these two hormones in the regulation of reproduction in teleost fishes, as well as a role for leptin as a catabolic stress hormone. In this review, we briefly explore the reproductive actions of leptin and cortisol in mammals and teleost fishes and possible role of both hormones as putative modulators of the reproductive axis during stress events.
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Affiliation(s)
- Coltan G Parker
- Neuroscience Program, Beckman Institute of Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N Mathews Ave, Urbana, IL, USA
| | - Eugene Cheung
- Department of Biological Sciences, David Clark Labs, 100 Brooks Avenue, North Carolina State University, Raleigh, NC, USA.
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4
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Mes D, van Os R, Gorissen M, Ebbesson LOE, Finstad B, Mayer I, Vindas MA. Effects of environmental enrichment on forebrain neural plasticity and survival success of stocked Atlantic salmon. ACTA ACUST UNITED AC 2019; 222:jeb.212258. [PMID: 31712354 DOI: 10.1242/jeb.212258] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022]
Abstract
Fish reared for stocking programmes are severely stimulus deprived compared with their wild conspecifics raised under natural conditions. This leads to reduced behavioural plasticity and low post-release survival of stocked fish. Environmental enrichment can have positive effects on important life skills, such as predator avoidance and foraging behaviour, but the neural mechanisms underpinning these behavioural changes are still largely unknown. In this study, juvenile Atlantic salmon (Salmo salar) were reared in an enriched hatchery environment for 7 weeks, after which neurobiological characteristics and post-release survival were compared with those of fish reared under normal hatchery conditions. Using in situ hybridization and qPCR, we quantified the expression of brain-derived neurotrophic factor (bdnf) and the neural activity marker cfos in telencephalic subregions associated with relational memory, emotional learning and stress reactivity. Aside from lower expression of bdnf in the Dlv (a region associated with relational memory) of enriched salmon, we observed no other significant effects of enrichment in the studied regions. Exposure to an enriched environment increased post-release survival during a 5 month residence in a natural river by 51%. Thus, we demonstrate that environmental enrichment can improve stocking success of Atlantic salmon parr and that environmental enrichment is associated with changes in bdnf expression in the fish's hippocampus-equivalent structure.
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Affiliation(s)
- Daan Mes
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Renske van Os
- Institute of Water and Wetland Research, Department of Animal Ecology and Physiology, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Marnix Gorissen
- Institute of Water and Wetland Research, Department of Animal Ecology and Physiology, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | | | - Bengt Finstad
- Norwegian Institute for Nature Research, 7485 Trondheim, Norway
| | - Ian Mayer
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Marco A Vindas
- Uni Environment, Uni Research AS, 5008 Bergen, Norway .,Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, 0454 Oslo, Norway.,Institute of Neuroscience and Physiology, University of Gothenburg, 413 90 Gothenburg, Sweden
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5
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McConnell CJ, Atkinson S, Oxman D, Westley PAH. Is blood cortisol or vateritic otolith composition associated with natal dispersal or reproductive performance on the spawning grounds of straying and homing hatchery-produced chum salmon ( Oncorhynchus keta) in Southeast Alaska? Biol Open 2019; 8:bio.042853. [PMID: 31182627 PMCID: PMC6602324 DOI: 10.1242/bio.042853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Homing with high fidelity to natal spawning grounds for reproduction is a hallmark of anadromous Pacific salmon biology, although low rates of dispersal (‘straying’) also occurs. Currently little is known about the proximate factors influencing straying, which limits our understanding of this fundamental biological phenomenon and impedes options for reducing straying-mediated interactions between wild and hatchery-produced individuals. We explored the potential role of stress experienced in captivity prior to intentional release to manifest in developmental irregularities and potentially influence rates of straying by adults. We compared two proxies for stress between groups of hatchery-produced individuals that had homed back to the hatchery or strayed to non-natal streams compared to wild individuals that were presumed to have homed to a wild spawning stream. Blood plasma cortisol was used to assess stress at the terminus of their migration, and percent frequency of vateritic otolith development within groups as a measure of stresses incurred during development. We found no evidence that either proxy for stress was associated with straying. No differences in cortisol concentrations were found between wild and hatchery-produced chum salmon that had homed or strayed, either in males (wild=95.9±175.7 ng/ml; stray=113.4±99.7 ng/ml; home=124.7±113.8 ng/ml) or females (wild=307.6±83.4 ng/ml; stray= 329.0±208.9 ng/ml; home=294.1±134.8 ng/ml); however, significant differences between males and females occurred in each group. The percent frequency of vaterite occurrence in otoliths of hatchery-produced chum salmon that either strayed (40% vaterite) or homed (45% vaterite) did not differ significantly, though rates of vaterite occurred less frequently in wild chum salmon (24%), which is consistent with other studies. Mass thermal marking of juvenile fish in hatcheries is unlikely to increase vateritic development as neither intensity (number of temperature changes) or complexity (number of temperature change sequences) of the mark was associated with frequency of vaterite occurrence. Though not associated with straying, cortisol concentrations were associated with shorter instream lifespan of both hatchery and wild individuals but did not appear to influence rates of egg retention in spawning females, suggesting an equivocal role in reproductive ecology. Our results are suggestive that stress induced during the early stages of rearing in a hatchery environment from marking or other causes may not increase straying later in life, though the higher rates of vaterite observed in hatchery-produced fish may come at a cost of increased marine mortality, due to the otoliths' role in navigation and hearing. Summary: Straying mediates ecological interactions and gene flow between salmon populations. Understanding physiological controls and underlying causes of straying by hatchery-produced salmon may help managers minimize deleterious interactions.
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Affiliation(s)
- Casey J McConnell
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 323 Garteeni Hwy, Hoonah, AK 99829, USA
| | - Shannon Atkinson
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 17101 Lena Point Loop Road, Juneau, AK 99801, USA
| | - Dion Oxman
- Alaska Department of Fish and Game, 10107 Bentwood Pl, Juneau, AK 9901, USA
| | - Peter A H Westley
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905. N Koyukuk Drive, Fairbanks, AK 99775, USA
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6
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'Central' Actions of Corticosteroid Signaling Suggested by Constitutive Knockout of Corticosteroid Receptors in Small Fish. Nutrients 2019; 11:nu11030611. [PMID: 30871191 PMCID: PMC6470806 DOI: 10.3390/nu11030611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/02/2019] [Accepted: 03/11/2019] [Indexed: 01/24/2023] Open
Abstract
This review highlights recent studies of the functional implications of corticosteroids in some important behaviors of model fish, which are also relevant to human nutrition homeostasis. The primary actions of corticosteroids are mediated by glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), which are transcription factors. Zebrafish and medaka models of GR- and MR-knockout are the first constitutive corticosteroid receptor-knockout animals that are viable in adulthood. Similar receptor knockouts in mice are lethal. In this review, we describe the physiological and behavioral changes following disruption of the corticosteroid receptors in these models. The GR null model has peripheral changes in nutrition metabolism that do not occur in a mutant harboring a point mutation in the GR DNA-binding domain. This suggests that these are not “intrinsic” activities of GR. On the other hand, we propose that integration of visual responses and brain behavior by corticosteroid receptors is a possible “intrinsic”/principal function potentially conserved in vertebrates.
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7
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Mes D, von Krogh K, Gorissen M, Mayer I, Vindas MA. Neurobiology of Wild and Hatchery-Reared Atlantic Salmon: How Nurture Drives Neuroplasticity. Front Behav Neurosci 2018; 12:210. [PMID: 30254575 PMCID: PMC6141658 DOI: 10.3389/fnbeh.2018.00210] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/21/2018] [Indexed: 12/03/2022] Open
Abstract
Life experiences in the rearing environment shape the neural and behavioral plasticity of animals. In fish stocking practices, the hatchery environment is relatively stimulus-deprived and does not optimally prepare fish for release into the wild. While the behavioral differences between wild and hatchery-reared fish have been examined to some extent, few studies have compared neurobiological characteristics between wild and hatchery-reared individuals. Here, we compare the expression of immediate early gene cfos and neuroplasticity marker brain-derived neurotrophic factor (bdnf) in telencephalic subregions associated with processing of stimuli in wild and hatchery-reared Atlantic salmon at basal and 30 min post (acute) stress conditions. Using in situ hybridization, we found that the expression level of these markers is highly specific per neuronal region and affected by both the origin of the fish, and exposure to acute stress. Expression of cfos was increased by stress in all brain regions and cfos was more highly expressed in the Dlv (functional equivalent to the mammalian hippocampus) of hatchery-reared compared to wild fish. Expression of bdnf was higher overall in hatchery fish, while acute stress upregulated bdnf in the Dm (functional equivalent to the mammalian amygdala) of wild, but not hatchery individuals. Our findings demonstrate that the hatchery environment affects neuroplasticity and neural activation in brain regions that are important for learning processes and stress reactivity, providing a neuronal foundation for the behavioral differences observed between wild and hatchery-reared fish.
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Affiliation(s)
- Daan Mes
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Kristine von Krogh
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Marnix Gorissen
- Department of Animal Ecology and Physiology, Institute of Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Ian Mayer
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Marco A Vindas
- Uni Environment, Uni Research AS, Bergen, Norway.,Department of Neurobiology and Physiology, University of Gothenburg, Gothenburg, Sweden.,Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
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8
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Kiilerich P, Servili A, Péron S, Valotaire C, Goardon L, Leguen I, Prunet P. Regulation of the corticosteroid signalling system in rainbow trout HPI axis during confinement stress. Gen Comp Endocrinol 2018; 258:184-193. [PMID: 28837788 DOI: 10.1016/j.ygcen.2017.08.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/13/2017] [Accepted: 08/11/2017] [Indexed: 12/17/2022]
Abstract
This study aims to shed light on corticosteroid regulation of stress in teleost fish with focus on the corticosteroid signalling system. The role of the mineralocorticoid-like hormone 11-deoxycorticosterone (DOC) in fish is still enigmatic, as is the function of the mineralocorticoid receptor, MR. Low plasma DOC levels and ubiquitous tissue distribution of MR question the physiological relevance of the mineralocorticoid-axis. Furthermore, the particular purpose of each of the three corticosteroid receptors in fish, the glucocorticoid receptors, GR1 and GR2, and the MR, is still largely unknown. Therefore we investigate the regulation of cortisol and DOC in plasma and mRNA levels of MR, GR1 and GR2 in the HPI-axis tissues (hypothalamus, pituitary and interrenal gland) during a detailed confinement stress time-course. Here we show a sustained up-regulation of plasma DOC levels during a confinement stress time-course. However, the low DOC levels compared to cortisol measured in the plasma do not favour an activity of DOC through MR receptors. Furthermore, we show differential contribution of the CRs in regulation and control of HPI axis activity following confinement stress. Judged by the variation of mRNA levels negative feedback regulation of cortisol release occurs on the level of the pituitary via MR and on the level of the interrenal gland via GR2. Finally, asa significant effect of confinement stress on CR expressions was observed in the pituitary gland, we completed this experiment by demonstrating that corticosteroid receptors (GR1, GR2 and MR) are co-expressed in the ACTH cells located in the adenohypophysis. Overall, these data suggest the involvement of these receptors in the regulation of the HPI axis activity by cortisol.
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Affiliation(s)
- Pia Kiilerich
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35042 Rennes, France.
| | - Arianna Servili
- Ifremer, Unité de Physiologie Fonctionnelle des Organismes Marins, LEMAR UMR 6539, BP 70, Plouzané 29280, France
| | - Sandrine Péron
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35042 Rennes, France
| | - Claudiane Valotaire
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35042 Rennes, France
| | - Lionel Goardon
- INRA, UE937 Pisciculture expérimentale des Monts d'Arrée, 29450 Sizun, France
| | - Isabelle Leguen
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35042 Rennes, France
| | - Patrick Prunet
- INRA, UR1037, Fish Physiology and Genomics, Campus de Beaulieu, 35042 Rennes, France.
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Vindas MA, Gorissen M, Höglund E, Flik G, Tronci V, Damsgård B, Thörnqvist PO, Nilsen TO, Winberg S, Øverli Ø, Ebbesson LOE. How do individuals cope with stress? Behavioural, physiological and neuronal differences between proactive and reactive coping styles in fish. ACTA ACUST UNITED AC 2017; 220:1524-1532. [PMID: 28167808 DOI: 10.1242/jeb.153213] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/01/2017] [Indexed: 12/19/2022]
Abstract
Despite the use of fish models to study human mental disorders and dysfunctions, knowledge of regional telencephalic responses in non-mammalian vertebrates expressing alternative stress coping styles is poor. As perception of salient stimuli associated with stress coping in mammals is mainly under forebrain limbic control, we tested region-specific forebrain neural (i.e. mRNA abundance and monoamine neurochemistry) and endocrine responses under basal and acute stress conditions for previously characterised proactive and reactive Atlantic salmon. Reactive fish showed a higher degree of the neurogenesis marker proliferating cell nuclear antigen (pcna) and dopamine activity under basal conditions in the proposed hippocampus homologue (Dl) and higher post-stress plasma cortisol levels. Proactive fish displayed higher post-stress serotonergic signalling (i.e. higher serotonergic activity and expression of the 5-HT1A receptor) in the proposed amygdala homologue (Dm), increased expression of the neuroplasticity marker brain-derived neurotropic factor (bdnf) in both Dl and the lateral septum homologue (Vv), as well as increased expression of the corticotropin releasing factor 1 (crf1 ) receptor in the Dl, in line with active coping neuro-profiles reported in the mammalian literature. We present novel evidence of proposed functional equivalences in the fish forebrain with mammalian limbic structures.
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Affiliation(s)
- Marco A Vindas
- Uni Environment, Uni Research AS, Bergen NO-5020, Norway .,Department of Biosciences, University of Oslo, Oslo NO-0316, Norway
| | - Marnix Gorissen
- Radboud University, Institute for Water and Wetland Research, Department of Animal Ecology & Physiology, Nijmegen 6525 AJ, The Netherlands
| | - Erik Höglund
- National Institute of Aquatic Resources, Technical University of Denmark, Hirtshals DK-9850, Denmark
| | - Gert Flik
- Radboud University, Institute for Water and Wetland Research, Department of Animal Ecology & Physiology, Nijmegen 6525 AJ, The Netherlands
| | | | - Børge Damsgård
- The University Centre of Svalbard, Longyearbyen NO-9171, Norway.,Nofima, Tromsø NO-9291, Norway
| | - Per-Ove Thörnqvist
- Department of Neuroscience, Uppsala University, Uppsala SE-75124, Sweden
| | - Tom O Nilsen
- Uni Environment, Uni Research AS, Bergen NO-5020, Norway
| | - Svante Winberg
- Department of Neuroscience, Uppsala University, Uppsala SE-75124, Sweden
| | - Øyvind Øverli
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo NO-0033, Norway
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10
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Shahbazi M, Schmidt M, Carruth LL. Distribution and subcellular localization of glucocorticoid receptor-immunoreactive neurons in the developing and adult male zebra finch brain. Gen Comp Endocrinol 2011; 174:354-61. [PMID: 21986090 DOI: 10.1016/j.ygcen.2011.09.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 09/12/2011] [Accepted: 09/25/2011] [Indexed: 01/14/2023]
Abstract
Stress has long lasting effects on physiology, development, behavior, reproductive success and the survival of an individual. These effects are mediated by glucocorticoids, such as corticosterone, via glucocorticoid receptors (GR), however the exact mechanisms underlying these effects are unknown. GR have been widely studied in mammals but little is known about GR in other vertebrate groups, especially songbirds. We investigated the distribution, quantity, and subcellular-localization of GR-immunoreactive (GRir) neurons in the brains of male zebra finches on P10 (post-hatch day 10, song nuclei formed), and in adulthood (post-hatch day 90 or older) using immunohistochemistry. GRir neurons were widely distributed in the brains of male zebra finches including two song nuclei HVC (acronym is a proper name) and RA (nucleus robustus arcopallii) and brain regions including HP (hippocampal formation), BSTl (lateral part of the bed nucleus of the stria terminalis), POM (nucleus preopticus medialis), PVN (nucleus paraventricularis magnocellularis), TeO (optic tectum), S (nucleus of the solitary tract), LoC (Locus coeruleus). Distribution did not vary at the two age points examined, however there were significant differences in staining intensity. Subcellular GR-immunoreactivity patterns were classified as cytoplasmic, nuclear, or both (cytoplasmic and nuclear) and there were significant differences in the overall number of GRir neurons and neurons with both nuclear and cytoplasmic staining in P10 and adult brains. However, there were no significant differences in the percentage of subcellular GR immunoreactivity patterns between P10 and adults. Our study of GRir neuronal distribution in the zebra finch brain may contribute towards understanding of the complex and adverse effects of stress on brain during two different stages of life history.
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Affiliation(s)
- Mahin Shahbazi
- Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, P.O. Box 5030, Atlanta, GA 30302-5030, USA
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11
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Corticotropin releasing factor influences aggression and monoamines: modulation of attacks and retreats. Neuroscience 2008; 158:412-25. [PMID: 18992791 DOI: 10.1016/j.neuroscience.2008.10.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 10/09/2008] [Accepted: 10/17/2008] [Indexed: 11/20/2022]
Abstract
Salmonids establish social hierarchies as a result of aggressive social interactions. The establishment of dominant or subordinate status is strongly linked to neuroendocrine responses mediated through the stress axis. In this study, we tested the effects of introcerebroventricular (icv) corticotropin releasing factor (CRF) on the behavioral outcome, plasma cortisol and monoamine function in trout subjected to a socially aggressive encounter. Rainbow trout were treated with an icv injection of artificial cerebrospinal fluid (aCSF), 500 or 2000 ng ovine CRF, or not injected. Fish were allowed to interact with a similarly sized conspecific for 15 min. Following the behavioral interaction, plasma cortisol and central monoamine concentrations were analyzed. Trout treated with CRF were victorious in approximately 66% of the aggressive encounters against aCSF-treated opponents. Trout injected with CRF exhibited a reduction in the total number of attacks and decreased latency to attack. When trout were divided into winners and losers, only victorious CRF-treated fish exhibited a reduced latency to attack and fewer retreats. Social stress increased cortisol levels in both winners and losers of aggressive interaction. This effect was enhanced with the additional stress incurred from icv injection of aCSF. However, icv CRF in addition to social stress decreased plasma cortisol in both winners and losers. While aggression stimulated significant changes in serotonergic and dopaminergic activity, the magnitude and direction were dependent on limbic brain region, CRF dose, and outcome of social aggression. With broad effects on aggressive behavior, anxiety, stress responsiveness, and central monoaminergic activity, CRF plays an important role in modulating the behavioral components of social interaction.
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12
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Yao M, Hu F, Denver RJ. Distribution and corticosteroid regulation of glucocorticoid receptor in the brain of Xenopus laevis. J Comp Neurol 2008; 508:967-82. [PMID: 18399546 DOI: 10.1002/cne.21716] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Glucocorticoids (GCs) play essential roles in physiology, development, and behavior that are mediated largely by the glucocorticoid receptor (GR). Although the GR has been intensively studied in mammals, very little is known about the GR in nonmammalian tetrapods. We analyzed the distribution and GC regulation of GR in the brain of the frog Xenopus laevis by immunohistochemistry. GR-immunoreactive (GR-ir) cells were widely distributed, with the highest densities in the medial pallium (mp; homolog of the mammalian hippocampus), accumbens, anterior preoptic area (POA; homolog of the mammalian paraventricular nucleus), Purkinje cell layer of the cerebellum, and rostral anterior pituitary gland (location of corticotropes). Lower but distinct GR-ir was observed in the internal granule cell layer of the olfactory bulbs, dorsal and lateral pallium, striatum, various subfields of the amygdala, bed nucleus of the stria terminalis (BNST), optic tectum, various tegmental nuclei, locus coeruleus, raphe nuclei, reticular nuclei, and the nuclei of the trigeminal motor nerves. Treatment with corticosterone (CORT) for 4 days significantly decreased GR-ir in the POA, mp, medial amygdala (MeA), BNST, and rostral pars distalis. Treatment with the corticosteroid synthesis inhibitor metyrapone (MTP) also significantly reduced GR-ir in the POA, mp, MeA and BNST, but not in the rostral pars distalis. Replacement with a low dose of CORT in MTP-treated animals reversed these effects in brain. Thus, chronic increase or decrease in circulating corticosteroids reduces GR-ir in regions of the frog brain. Our results show that the central distribution of GR-ir and regulation by corticosteroids are highly conserved among vertebrates.
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Affiliation(s)
- Meng Yao
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, Michigan 48109-1048, USA
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Carpenter RE, Watt MJ, Forster GL, Øverli Ø, Bockholt C, Renner KJ, Summers CH. Corticotropin releasing factor induces anxiogenic locomotion in trout and alters serotonergic and dopaminergic activity. Horm Behav 2007; 52:600-11. [PMID: 17826776 PMCID: PMC3889481 DOI: 10.1016/j.yhbeh.2007.07.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/20/2007] [Accepted: 07/27/2007] [Indexed: 11/17/2022]
Abstract
Corticotropin releasing factor (CRF) and serotonin (5-HT) are strongly linked to stress and anxiety in vertebrates. As a neuromodulator in the brain, CRF has anxiogenic properties often characterized by increased locomotion and stereotyped behavior in familiar environments. We hypothesized that expression of anxiogenic behavior in response to CRF will also be exhibited in a teleost fish. Rainbow trout were treated with intracerebroventricular (icv) injections of artificial cerebrospinal fluid (aCSF), 500 or 2000 ng ovine CRF, or not injected. Treatment with either dose of CRF elicited greater locomotion and pronounced head shaking behavior but did not influence water column position. Locomotor and head shaking behaviors may be analogous to the increased stereotypy evoked by icv CRF in rats and may reflect the expression of stress/anxiety behavior. Injection with either aCSF or CRF produced significant increases in plasma cortisol. The absence of behavioral changes in aCSF-injected fish suggests that the behavioral responses following CRF were not due to cortisol. Treatment with 2000 ng CRF significantly increased serotonin, 5-HIAA and dopamine concentrations in the subpallium and raphé and increased 5-HIAA in the preoptic hypothalamus (POA). Concurrent effects of CRF on central monoamines, locomotion and head shaking in trout suggest that anxiogenic properties of CRF are evolutionarily conserved. In addition, positive linear correlations between locomotion and serotonergic and dopaminergic function in the subpallium, POA and raphé nuclei suggest a locomotory function for these monoamines.
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Affiliation(s)
- Russ E. Carpenter
- Department of Biology, University of South Dakota, Vermillion, SD 57069 USA
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069 USA
| | - Michael J. Watt
- Department of Biology, University of South Dakota, Vermillion, SD 57069 USA
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069 USA
| | - Gina L. Forster
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069 USA
| | - Øyvind Øverli
- Department of Biology, University of South Dakota, Vermillion, SD 57069 USA
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Aas, Norway
| | - Craig Bockholt
- U.S. Fish and Wildlife Service, Gavins Point National Fish Hatchery, Yankton, SD 57078 USA
| | - Kenneth J. Renner
- Department of Biology, University of South Dakota, Vermillion, SD 57069 USA
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069 USA
| | - Cliff H. Summers
- Department of Biology, University of South Dakota, Vermillion, SD 57069 USA
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069 USA
- Corresponding author: Cliff H. Summers, Ph.D., Department of Biology, University of South Dakota, 414 East Clark Street, Vermillion, SD 57069-2390, 605 677 6177, , fax: 605 677 6557
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Sørensen C, Øverli Ø, Summers CH, Nilsson GE. Social Regulation of Neurogenesis in Teleosts. BRAIN, BEHAVIOR AND EVOLUTION 2007; 70:239-46. [PMID: 17914255 DOI: 10.1159/000105487] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Salmonid fishes such as the rainbow trout (Oncorhynchus mykiss) are frequently used to study behavioral and neuroendocrine effects of socially induced stress. A predictable aggressive response to territorial intrusion, a well described neuroanatomy, and many essential similarities in the stress response in fishes and other vertebrates are among the advantages of this comparative model. One conspicuous difference when compared to mammals, however, is that in teleost fish and other non-mammalian vertebrates, neurogenesis persists into adulthood to a much higher degree. Very little is known about the functional significance of individual differences in the rate of brain cell proliferation in fish, or whether structural changes in the fish brain are influenced by the social environment. In this paper we discuss the observation that brain cell proliferation is reduced in subordinate fish, focusing in particular on whether such individual variation reflects a difference in coping style or is indeed a response to social interactions.
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Mazon AF, Nolan DT, Lock RAC, Fernandes MN, Wendelaar Bonga SE. A short-term in vitro gill culture system to study the effects of toxic (copper) and non-toxic (cortisol) stressors on the rainbow trout, Oncorhynchus mykiss (Walbaum). Toxicol In Vitro 2004; 18:691-701. [PMID: 15251188 DOI: 10.1016/j.tiv.2004.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Accepted: 03/17/2004] [Indexed: 10/26/2022]
Abstract
A short-term (24 h) method of gill filament culture system was developed to predict the effects of environmental contamination and stress in fish. Gill culture system containing two or three rainbow trout gill filaments in sterile glutamine supplemented Leibovitz 15 (L-15) media was submitted for 24 h to six different treatments: (i) CONT (control, medium only); (ii) CORT (cortisol, 0.28 microM cortisol); (iii) BLOCK (glucocorticoid receptor blocker, 14 microM RU 486); (iv) CORT+BLOCK (cortisol and blocker, 0.28 microM cortisol+14 microM RU 486); (v) CORT+CU (cortisol and copper, 100 microM CuSO4+0.28 microM cortisol); (vi) CU (copper, 100 microM CuSO4). After 24 h, the overall gill structure and cellular components resembled those of salmonids in vivo. Lactate dehydrogenase (LDH) activity in the culture media increased in the CORT+CU and CU groups but was significantly lower in the CORT+CU compared to CU group. Apoptotic cells increased in the CORT and CORT+BLOCK. The numbers of glucocorticoid (GR) receptor-positive cells were lower in the CU group. This short-term culture system seems to be suitable for studying the effects of both external and internal stress effectors (toxicants and hormones respectively), as it contains all cell types found in the gills and the cells give similar biological response as in vivo.
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Affiliation(s)
- A F Mazon
- Department of Physiological Sciences, Federal University of São Carlos, Rod. Washington Luiz, km 235, P.O. Box 676, 13565-905 São Carlos, SP, Brazil
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16
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Chandroo K, Duncan I, Moccia R. Can fish suffer?: perspectives on sentience, pain, fear and stress. Appl Anim Behav Sci 2004. [DOI: 10.1016/j.applanim.2004.02.004] [Citation(s) in RCA: 237] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Øverli Ø, Korzan WJ, Larson ET, Winberg S, Lepage O, Pottinger TG, Renner KJ, Summers CH. Behavioral and neuroendocrine correlates of displaced aggression in trout. Horm Behav 2004; 45:324-9. [PMID: 15109906 DOI: 10.1016/j.yhbeh.2004.01.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2003] [Revised: 09/25/2003] [Accepted: 01/06/2004] [Indexed: 10/26/2022]
Abstract
In humans and other primates, violent actions performed by victims of aggression are often directed toward an individual or object that is not the source of provocation. This psychological phenomenon is often called displaced aggression. We demonstrate that displaced aggression is either rooted in evolutionarily conserved behavioral and neuroendocrine mechanisms, or represent a convergent pattern that has arisen independently in fish and mammals. Rainbow trout that briefly encountered large, aggressive fish reacted with increased aggression toward smaller individuals. There was a strong negative correlation between received aggression and behavioral change: Individuals subjected to intense aggression were subdued, while moderate assaults induced strong agitation. Patterns of forebrain serotonin turnover and plasma cortisol suggest that the presence of socially subordinate fish had an inhibitory effect on neuroendocrine stress responses. Thus, subordinate individuals may serve as stress-reducing means of aggressive outlet, and displaced aggression toward such individuals appears to be a behavioral stress coping strategy in fishes.
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Affiliation(s)
- Øyvind Øverli
- Biology Department and Neuroscience Group, University of South Dakota, Vermillion, SD 57069, USA.
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18
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Abstract
Environmental and social stresses have deleterious effects on reproductive function in vertebrates. Global climate change, human disturbance and endocrine disruption from pollutants are increasingly likely to pose additional stresses that could have a major impact on human society. Nonetheless, some populations of vertebrates (from fish to mammals) are able to temporarily resist environmental and social stresses, and breed successfully. A classical trade-off of reproductive success for potential survival is involved. We define five examples. (i) Aged individuals with minimal future reproductive success that should attempt to breed despite potential acute stressors. (ii) Seasonal breeders when time for actual breeding is so short that acute stress should be resisted in favour of reproductive success. (iii) If both members of a breeding pair provide parental care, then loss of a mate should be compensated for by the remaining individual. (iv) Semelparous species in which there is only one breeding period followed by programmed death. (v) Species where, because of the transience of dominance status in a social group, individuals may only have a short window of opportunity for mating. We suggest four mechanisms underlying resistance of the gonadal axis to stress. (i) Blockade at the central nervous system level, i.e. an individual no longer perceives the perturbation as stressful. (ii) Blockade at the level of the hypothalamic-pituitary-adrenal axis (i.e. failure to increase secretion of glucocorticosteroids). (iii) Blockade at the level of the hypothalamic-pituitary-gonad axis (i.e. resistance of the reproductive system to the actions of glucocorticosteroids). (iv) Compensatory stimulation of the gonadal axis to counteract inhibitory glucocorticosteroid actions. Although these mechanisms are likely genetically determined, their expression may depend upon a complex interaction with environmental factors. Future research will provide valuable information on the biology of stress and how organisms cope. Such mechanisms would be particularly insightful as the spectre of global change continues to unfold.
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Affiliation(s)
- J C Wingfield
- Department of Biology, University of Washington, Seattle, WA 98195, USA.
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Pepels PPLM, Meek J, Wendelaar Bonga SE, Balm PHM. Distribution and quantification of corticotropin-releasing hormone (CRH) in the brain of the teleost fish Oreochromis mossambicus (tilapia). J Comp Neurol 2002; 453:247-68. [PMID: 12378586 DOI: 10.1002/cne.10377] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The recent characterization of the corticotropin-releasing hormone (CRH) prehormone of the fish tilapia (Oreochromis mossambicus) showed that more variation exists between vertebrate CRH amino acid sequences than recognized before. The present study investigates whether the deviating composition of tilapia CRH coincides with an atypical distribution of CRH in the brain. For this purpose we applied immunohistochemistry, as well as radioimmunoassay (RIA) quantification in brain slices. The results are plotted in a new atlas and reconstruction of the tilapia brain. The largest population of CRH-immunoreactive (ir) neurons is present in the lateral part of the ventral telencephalon (Vl). Approximately tenfold less CRH-ir neurons are observed in the preoptic and tuberal region. The CRH-ir neurons observed in the preoptic region are parvocellular and do not, or hardly, display arginine-vasotocin (AVT) immunoreactivity. CRH-ir neurons are also present in the glomerular layer of the olfactory bulb, in the periventricular layer of the optic tectum, and caudal to the glomerular nucleus. A very dense plexus of CRH-ir terminals is located in the most rostral part of the dorsal telencephalon. This region has not been described in other teleosts and is in the present study subdivided into the anterior part of the dorsal telencephalon (Da) and the anterior part of the laterodorsal telencephalon (Dla). High densities of CRH-ir terminals were observed in and around Vl, in the tuberal region, around the rostral part of the lateral recess, and in the caudal part of the vagal lobe. In the pituitary, CRH-ir terminals are concentrated in the neuro-intermediate lobe. Overall, the immunohistochemical and quantitative data correlated well, as the RIA CRH profile in serial 160-microm slices revealed four peaks, which corresponded with major ir-cell groups and terminal fields. Our results strongly suggest that the CRH-ir cells of Vl project to the rostro-dorsal telencephalon. Consequently, they may not be primarily involved in regulation of pituitary cell types but may subserve other functions. The presence of a CRH-containing Vl-Da/Dla projection seems to be restricted to the most modern group of teleosts, i.e., the Acanthopterygians. Further anatomic indications for non-pituitary-related functions of CRH are found in the vagal lobe and the optic tectum of tilapia. Although the low CRH content of the preoptic region reported here for tilapia may be typical for unstressed fish, the fact remains that remarkably few CRH-ir neurons are involved in regulating the pituitary. Overall, the CRH distribution in the brain of tilapia is more widespread than previously reported for other teleosts.
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Affiliation(s)
- Peter P L M Pepels
- Department of Animal Physiology, Faculty of Science, University of Nijmegen, 6525 ED Nijmegen, The Netherlands.
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20
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Maldonado TA, Jones RE, Norris DO. Intraneuronal amyloid precursor protein (APP) and appearance of extracellular beta-amyloid peptide (abeta) in the brain of aging kokanee salmon. JOURNAL OF NEUROBIOLOGY 2002; 53:11-20. [PMID: 12360579 DOI: 10.1002/neu.10086] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Antibodies to human amyloid precursor protein (APP(695)) and beta-amyloid peptide (A beta(1-42)) were used to determine timing of amyloidosis in the brain of kokanee salmon (Oncorhynchus nerka kennerlyi) in one of four reproductive stages: immature (IM), maturing (MA), sexually mature (SM), and spawning (SP), representing a range of aging from somatically mature but sexually immature to spawning and somatic senescence. In IM fish, immunoreactive (ir) intracellular APP occurred in 18 of 23 brain regions. During sexual maturation and aging, the number of neurons expressing APP increased in 11 of these APP-ir regions. A beta-ir was absent in IM fish, present in seven regions in MA fish, moderately abundant in 15 regions in SM fish, and was most abundant in all brain regions of SP fish exhibiting A beta-ir. Intracellular APP-ir was observed in brain regions involved in sensory integration, olfaction, vision, stress responses, reproduction, and coordination. Intra- and extracellular A beta(1-42) immunoreactivity (A beta-ir) was present in all APP-ir regions except the nucleus lateralis tuberis (hypothalamus) and Purkinje cells (cerebellum). APP-ir and A beta deposition increase during aging. APP-ir is present in IM fish; A beta-ir usually appears first in MA or SM fish and increases in SM fish as does APP-ir. Extracellular A beta deposition dramatically increases between SM and SP stages (1-2 weeks) in all fish, indicating an extremely rapid and synchronized process. Rapid senescence observed in pacific salmon could make them a useful model to investigate timing of amyloidosis and neurodegeneration during brain aging.
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Affiliation(s)
- Tammy A Maldonado
- Department of EPO Biology, University of Colorado, 334 UCB, Boulder, Colorado 80309-0334, USA
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21
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Maldonado TA, Jones RE, Norris DO. Timing of neurodegeneration and beta-amyloid (Abeta) peptide deposition in the brain of aging kokanee salmon. JOURNAL OF NEUROBIOLOGY 2002; 53:21-35. [PMID: 12360580 DOI: 10.1002/neu.10090] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Brains of kokanee salmon (Oncorhynchus nerka kennerlyi) in one of four reproductive stages (sexually immature, maturing, sexually mature, and spawning) were stained with cresyl violet and silver stain to visualize neurodegeneration. These reproductive stages correlate with increasing somatic aging of kokanee salmon, which die after spawning. Twenty-four regions of each brain were examined. Brains of sexually immature fish exhibited low levels of neurodegeneration, whereas neurodegeneration was more marked in maturing fish and greatest in spawning fish. Neurodegeneration was present in specific regions of the telencephalon, diencephalon, mesencephalon, and rhombencephalon. Pyknotic neurons were observed in all regions previously reported to be immunopositive for A beta. Regions that did not exhibit neurodegeneration during aging included the magnocellular vestibular nucleus, the nucleus lateralis tuberis of the hypothalamus, and Purkinje cells of the cerebellum, all of which also lack A beta; perhaps these regions are neuroprotected. In 14 of 16 brain areas for which data were available on both the increase in A beta deposition and pyknosis, neurodegeneration preceded or appeared more or less simultaneously with A beta production, whereas in only two regions did A beta deposition precede neurodegeneration. This information supports the hypothesis that A beta deposition is a downstream product of neurodegeneration in most brain regions. Other conclusions are that the degree of neurodegeneration varies among brain regions, neurodegeneration begins in maturing fish and peaks in spawning fish, the timing of neurodegeneration varies among brain regions, and some regions do not exhibit accelerated neurodegeneration during aging.
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Affiliation(s)
- Tammy A Maldonado
- Department of Environmental, Population and Organismic Biology, University of Colorado, 334 UCB, Boulder, Colorado 80309-0334, USA
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22
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Dunlap KD, Pelczar PL, Knapp R. Social interactions and cortisol treatment increase the production of aggressive electrocommunication signals in male electric fish, Apteronotus leptorhynchus. Horm Behav 2002; 42:97-108. [PMID: 12367563 DOI: 10.1006/hbeh.2002.1807] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Brown ghost knife fish, Apteronotus leptorhynchus, continually emit a weakly electric discharge that serves as a communication signal and is sensitive to sex steroids. Males modulate this signal during bouts of aggression by briefly (approximately 15 ms) increasing the discharge frequency in signals termed "chirps." The present study examined the effects of short-term (1-7 days) and long-term (6-35 days) male-male interaction on the continuous electric organ discharge (EOD), chirping behavior, and plasma levels of cortisol and two androgens, 11-ketotestosterone (11KT) and testosterone. Males housed in isolation or in pairs were tested for short-term and long-term changes in their EOD frequency and chirping rate to standardized sinusoidal electrical stimuli. Within 1 week, chirp rate was significantly higher in paired fish than in isolated fish, but EOD frequency was equivalent in these two groups of fish. Plasma cortisol levels were significantly higher in paired fish than in isolated fish, but there was no difference between groups in plasma 11KT levels. Among paired fish, cortisol levels correlated positively with chirp rate. To determine whether elevated cortisol can cause changes in chirping behavior, isolated fish were implanted with cortisol-filled or empty Silastic tubes and tested for short-term and long-term changes in electrocommunication signals and steroid levels. After 2 weeks, fish that received cortisol implants showed higher chirp rates than blank-implanted fish; there were no difference between groups in EOD frequency. Cortisol implants significantly elevated plasma cortisol levels compared to blank implants but had no effect on plasma 11KT levels. These results suggest that male-male interaction increases chirp rate by elevating levels of plasma cortisol, which, in turn, acts to modify neural activity though an 11KT-independent mechanism.
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Affiliation(s)
- Kent D Dunlap
- Department of Biology, Trinity College, Hartford, Connecticut 06106, USA
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23
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Patel PD, Lopez JF, Lyons DM, Burke S, Wallace M, Schatzberg AF. Glucocorticoid and mineralocorticoid receptor mRNA expression in squirrel monkey brain. J Psychiatr Res 2000; 34:383-92. [PMID: 11165305 DOI: 10.1016/s0022-3956(00)00035-2] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Corticosteroids have been implicated in hippocampal atrophy in patients with severe psychiatric disorders, but little is known about receptor expression for corticosteroids in human or nonhuman primate brain. Both the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) were surveyed in this study of squirrel monkey brain using in situ hybridization histochemistry. Regions of high GR mRNA levels included CA1 and CA2 of hippocampus, dentate gyrus, paraventricular hypothalamus, lateral geniculate, lateral>medial amygdala, and cerebellum. Western analysis confirmed that GR immunoreactivity in squirrel monkey brain tissue most likely reflects the alpha isoform. Regions of high MR mRNA levels included all hippocampal pyramidal cell fields, dentate gyrus granule cell layer, lateral septum, medial>lateral amygdala, and to a lesser extent, cerebellum. Low levels of MR were also expressed in caudate and putamen. Receptor expression for corticosteroids in deep brain structures and the hippocampal formation was similar to that previously reported in rodents, but GR and MR mRNA were expressed at higher levels in squirrel monkey cerebral cortex. GR expression was evident in all cortical layers, particularly the pyramidal cell-rich layers II/III and V. MR expression was restricted to the more superficial cortical layers, and was only moderately represented in layer V. Laminar patterns were apparent in all regions of cortex for GR expression in squirrel monkeys, but low MR mRNA levels were found in dorsomedial prefrontal cortex (PFC). Different subregional distributions and distinctive laminar patterns suggest specialized functions or coordinated interactions between GR and MR mediated functions in primate PFC.
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Affiliation(s)
- P D Patel
- Mental Health Research Institute, University of Michigan Medical Center, 3064 NSL, 1103 East Huron Street, Ann Arbor, MI 48104-1687, USA.
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Carruth LL, Dores RM, Maldonado TA, Norris DO, Ruth T, Jones RE. Elevation of plasma cortisol during the spawning migration of landlocked kokanee salmon (Oncorhynchus nerka kennerlyi). Comp Biochem Physiol C Toxicol Pharmacol 2000; 127:123-31. [PMID: 11083023 DOI: 10.1016/s0742-8413(00)00140-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Kokanee salmon (Oncorhynchus nerka kennerlyi ), a landlocked subspecies of sockeye salmon, exhibited hypothalamic-pituitary interrenal (HPI, adrenal homologue) axis activation and an increase in plasma cortisol concentration up to 639 +/- 55.9 ng/ml in association with upstream migration in the upper Colorado River even though they were not exposed to a change in salinity and lengthy migration. Kokanee salmon were collected at various stages of migration and concomitant sexual maturation. The pattern of cortisol elevation in kokanee is similar to that in ocean-run sockeye salmon (O. nerka nerka). The presence of plasma cortisol elevation in an upstream migrating, landlocked Pacific salmon suggests that stressors previously considered to cause the cortisol increase, such as long-distance migration and changes in salinity, may not be primary causes of the HPI axis activation.
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Affiliation(s)
- L L Carruth
- Department of Physiological Science, University of California, Los Angeles, CA 90095-1527, USA.
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25
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Maldonado TA, Jones RE, Norris DO. Distribution of beta-amyloid and amyloid precursor protein in the brain of spawning (senescent) salmon: a natural, brain-aging model. Brain Res 2000; 858:237-51. [PMID: 10708675 DOI: 10.1016/s0006-8993(99)02328-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Brain amyloid precursor protein (APP), a normal constituent of neurons, glial cells and cerebrospinal fluid, has several proposed functions (e.g., in neuronal growth and survival). It appears, however, that altered processing of APP is an initial or downstream step in the neuropathology of brain aging, Alzheimer's disease (AD), and Down's syndrome (DS). Some studies suggest that proteolytic cleavage of APP, producing beta-amyloid (Abeta(1-42)), could have neurotoxic or neuroprotective effects. In this study, we utilized antibodies to human APP(695) and Abeta(1-42,) and Congo red staining, to search for amyloid deposition in the brain of semelparous spawning kokanee salmon (Oncorhynchus nerka kennerlyi). Intracellular APP(695) immunoreactivity (APP-ir) was observed in brain regions involved in gustation (glomerulosus complex), olfaction (putative hippocampus, olfactory bulb), vision (optic tectum), the stress response (nucleus preopticus and nucleus lateralis tuberis), reproductive behavior (nucleus preopticus magnocellularis, nucleus preopticus periventricularis, ventral telencephalon), and coordination (cerebellum). Intra- and extra-neuronal Abeta(1-42) immunoreactivity (Abeta-ir) were present in all APP-ir regions except the nucleus lateralis tuberis and Purkinje cells of the cerebellum (coordination). Thus, the relationship between APP and Abeta deposition during brain aging could shed light on the processing of APP into Abeta, neurodegeneration, and possible protection of neurons that are functioning in spawning but senescent salmon. Pacific salmon, with their predictable and synchronized life history, could provide research options not available with the existing models for studies of brain aging and amyloidosis.
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Affiliation(s)
- T A Maldonado
- Laboratory of Comparative Reproduction, Department of Environmental, Population and Organismic Biology, University of Colorado, Campus Box 334, Boulder, CO 80309-0334, USA.
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