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Rodrigues J, Rosa-Silva M, Tercya H, Jesus P, Miranda S, Oliveira H, Lima B, Santos L, Maximino C, Siqueira-Silva D. Oogenesis and in vitro reproduction of the twospot astyanax Astyanax bimaculatus (Linnaeus, 1758) exposed to conspecific alarm substance. Anim Reprod Sci 2023; 253:107252. [PMID: 37209522 DOI: 10.1016/j.anireprosci.2023.107252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/22/2023]
Abstract
Stress situations can be essential to trigger reproduction in fish; however, it may also inhibit it. One of those situations involves the release of the conspecific alarm substance (CAS), a natural stressor, into the water by specific fish epidermal cells after a predator attack. Little is known about the effects of that substance on fish reproduction. This study aimed to evaluate the effects of CAS exposure on the oogenesis and reproduction of the twospot astyanax Astyanax bimaculatus before the hormonal induction for artificial reproduction. No macroscopic or cellular changes in the ovaries were observed for the females exposed to CAS, and the oocyte stages show all females in the same phase of maturation (Spawning Capable). Females exposed to CAS spawned 20 min before the females without exposure. On the other hand, they ovulated only once, whereas the females from the control group ovulated multiple times for approximately two hours after hormonal induction. Moreover, the precocious ovulation of the females submitted to CAS did not generate offspring, since all generated zygotes did not develop. In contrast, the control group females produced more than 11 thousand healthy larvae. Exposing the female fish to CAS during their reproductive management in captivity may reduce breeding success.
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Affiliation(s)
- Jeane Rodrigues
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Graduate Program in Animal Reproduction in the Amazon (ReproAmazon) of the Federal Rural University of the Amazon (Ufra) and Federal University of Pará (UFPA), Av. Presidente Tancredo Neves, Nº 2501, Terra Firme, 66.077-830 Belém, PA, Brazil
| | - Maria Rosa-Silva
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Hadda Tercya
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Paulo Jesus
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Saynara Miranda
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Graduate Program in Animal Reproduction in the Amazon (ReproAmazon) of the Federal Rural University of the Amazon (Ufra) and Federal University of Pará (UFPA), Av. Presidente Tancredo Neves, Nº 2501, Terra Firme, 66.077-830 Belém, PA, Brazil
| | - Hingrid Oliveira
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Bianca Lima
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Ludmylla Santos
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Caio Maximino
- Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil
| | - Diógenes Siqueira-Silva
- Research Group of Studies on the Reproduction of Amazon Fish (GERPA/LANEC), Biology Faculty (FACBIO), Federal University of South and Southern of Pará (Unifesspa), Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Neuroscience and Behavior Laboratory "Frederico Guilherme Graeff" (LANEC), Psychology University, Institute of Healthy and Biologics Studies, Federal University of South and Southern of Pará, Av. dos Ipês, S/N, 68507-590 Marabá, PA, Brazil; Graduate Program in Animal Reproduction in the Amazon (ReproAmazon) of the Federal Rural University of the Amazon (Ufra) and Federal University of Pará (UFPA), Av. Presidente Tancredo Neves, Nº 2501, Terra Firme, 66.077-830 Belém, PA, Brazil.
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Tan ML, Xie CT, Tu X, Li YW, Chen QL, Shen YJ, Liu ZH. Short daylight photoperiod alleviated alarm substance-stimulated fear response of zebrafish. Gen Comp Endocrinol 2023; 338:114274. [PMID: 36940834 DOI: 10.1016/j.ygcen.2023.114274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/11/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023]
Abstract
Photoperiod has been well-documented to be involved in regulating many activities of animals. However, whether photoperiod takes part in mood control, such as fear response in fish and the underlying mode(s) of action remain unclear. In this study, adult zebrafish males and females (Danio rerio) were exposed to different photoperiods, Blank (12 h light: 12 h dark), Control (12 h light: 12 h dark), Short daylight (SD, 6 h light: 18 h dark) and Long daylight (LD, 18 h light: 6 h dark) for 28 days. After exposure, fear response of the fish was investigated using a novel tank diving test. After alarm substance administration, the onset to higher half, total duration in lower half and duration of freezing in SD-fish were significantly decreased, suggesting that short daylight photoperiod is capable of alleviating fear response in zebrafish. In contrast, comparing with the Control, LD didn't show significant effect on fear response of the fish. Further investigation revealed that SD increased the levels of melatonin (MT), serotonin (5-HT) and dopamine (DA) in the brain while decreased the plasma level of cortisol comparing to the Control. Moreover, the expressions of genes in MT, 5-HT and DA pathways and HPI axis were also altered consistently. Our data indicated that short daylight photoperiod might alleviate fear response of zebrafish probably through interfering with MT/5-HT/DA pathways and HPI axis.
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Affiliation(s)
- Mei-Ling Tan
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Cheng-Ting Xie
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Xin Tu
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Ying-Wen Li
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Qi-Liang Chen
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Yan-Jun Shen
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Zhi-Hao Liu
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China.
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Afferent and efferent connections of the nucleus posterior tuberis in the firemouth cichlid, Thorichthys meeki. Neurosci Res 2023; 186:10-20. [PMID: 36007624 DOI: 10.1016/j.neures.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 01/04/2023]
Abstract
The nucleus posterior tuberis (NPT) in teleost fishes, also called posterior tuberal nucleus, is situated in the posterior tuberculum of the diencephalon. It is fused across the midline and densely packed with small cells, but little is known about its connections. In this study, the afferent and efferent connections of the NPT were examined by means of tracer applications of the carbocyanine dye DiI in the firemouth cichlid, Thorichthys meeki. Retrogradely labeled cell bodies were found in the corpus mamillare and nucleus periventricularis of the inferior lobe; and anterogradely labeled terminal fibers were detected in the medial zone of the dorsal telencephalon, medial part of the nucleus lateralis tuberis, dorsal posterior thalamic nucleus, torus lateralis, medial part of the nucleus diffusus of the inferior lobe, and tectum opticum. All these connections show an ipsilateral tendency. The NPT is apparently a significant relay nucleus in the diencephalon of T. meeki, and possibly involved in a variety of feedback circuits. It seems also to be part of a tecto-hypothalamo-telencephalic pathway in cichlids.
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Norland S, Eilertsen M, Rønnestad I, Helvik JV, Gomes AS. Mapping key neuropeptides involved in the melanocortin system in Atlantic salmon (Salmo salar) brain. J Comp Neurol 2023; 531:89-115. [PMID: 36217593 PMCID: PMC9828751 DOI: 10.1002/cne.25415] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 01/12/2023]
Abstract
The melanocortin system is a key regulator of appetite and food intake in vertebrates. This system includes the neuropeptides neuropeptide y (NPY), agouti-related peptide (AGRP), cocaine- and amphetamine-regulated transcript (CART), and pro-opiomelanocortin (POMC). An important center for appetite control in mammals is the hypothalamic arcuate nucleus, with neurons that coexpress either the orexigenic NPY/AGRP or the anorexigenic CART/POMC neuropeptides. In ray-finned fishes, such a center is less characterized. The Atlantic salmon (Salmo salar) has multiple genes of these neuropeptides due to whole-genome duplication events. To better understand the potential involvement of the melanocortin system in appetite and food intake control, we have mapped the mRNA expression of npy, agrp, cart, and pomc in the brain of Atlantic salmon parr using in situ hybridization. After identifying hypothalamic mRNA expression, we investigated the possible intracellular coexpression of npy/agrp and cart/pomc in the tuberal hypothalamus by fluorescent in situ hybridization. The results showed that the neuropeptides were widely distributed, especially in sensory and neuroendocrine brain regions. In the hypothalamic lateral tuberal nucleus, the putative homolog to the mammalian arcuate nucleus, npya, agrp1, cart2b, and pomca were predominantly localized in distinct neurons; however, some neurons coexpressed cart2b/pomca. This is the first demonstration of coexpression of cart2b/pomca in the tuberal hypothalamus of a teleost. Collectively, our data suggest that the lateral tuberal nucleus is the center for appetite control in salmon, similar to that of mammals. Extrahypothalamic brain regions might also be involved in regulating food intake, including the olfactory bulb, telencephalon, midbrain, and hindbrain.
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Affiliation(s)
- Sissel Norland
- Department of Biological SciencesUniversity of BergenBergenNorway
| | | | - Ivar Rønnestad
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Jon Vidar Helvik
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Ana S. Gomes
- Department of Biological SciencesUniversity of BergenBergenNorway
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Azeredo R, Machado M, Pereiro P, Barany A, Mancera JM, Costas B. Acute Inflammation Induces Neuroendocrine and Opioid Receptor Genes Responses in the Seabass Dicentrarchus labrax Brain. BIOLOGY 2022; 11:biology11030364. [PMID: 35336737 PMCID: PMC8945561 DOI: 10.3390/biology11030364] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 12/05/2022]
Abstract
Simple Summary It is generally accepted (in mammals and in teleost fish, too) that stressful conditions affect the performance of an immune response. What is still far from being known is at what extend does an immune process affects the neuroendocrine system. Vaccination for instance, is nowadays a common practice in aquaculture and little is known about its physiological implications other than immunization. Here is a first approach to the study of the European seabass’ brain gene expression patterns in response to a peripheral inflammatory process. Genes related to the stress response were focused, along with those related to the opioid system. Increased expression of certain genes suggests the activation of a stress response triggered by inflammatory signals. Additionally, contrasting expression patterns of the same gene (increased vs decreased) in the different brain regions (as well as the time needed for changes to happen) point at different functions. These results clearly show the reactivity of different brain responses to an immune response, highlighting the importance of further studies on downstream implications (behavior, feeding, welfare, reproduction). Abstract In fish, as observed in mammals, any stressful event affects the immune system to a larger or shorter extent. The neuroendocrine-immune axis is a bi-directional network of mobile compounds and their receptors that are shared between both systems (neuroendocrine and immune) and that regulate their respective responses. However, how and to what extent immunity modulates the neuroendocrine system is not yet fully elucidated. This study was carried out to understand better central gene expression response patterns in a high-valued farmed fish species to an acute peripheral inflammation, focusing on genes related to the hypothalamus-pituitary-interrenal axis and the opioid system. European seabass, Dicentrarchus labrax, were intra-peritoneally injected with either Freund’s Incomplete Adjuvant to induce a local inflammatory response or Hanks Balances Salt Solution to serve as the control. An undisturbed group was also included to take into account the effects due to handling procedures. To evaluate the outcomes of an acute immune response, fish were sampled at 4, 24, 48, and 72 h post-injection. The brain was sampled and dissected for isolation of different regions: telencephalon, optic tectum, hypothalamus, and pituitary gland. The expression of several genes related to the neuroendocrine response was measured by real-time PCR. Data were statistically analyzed by ANOVA and discriminant analyses to obtain these genes’ responsiveness for the different brain regions. Serotonergic receptors were upregulated in the telencephalon, whereas the optic tectum inhibited these transcription genes. The hypothalamus showed a somewhat delayed response in which serotonin and glucocorticoid receptors were concerned. Still, the hypothalamic corticotropin-releasing hormone played an important role in differentiating fish undergoing an inflammatory response from those not under such conditions. Opioid receptors gene expression increased in both the hypothalamus and the telencephalon, while in the optic tectum, most were downregulated. However, no changes in the pituitary gland were observed. The different brain regions under immune stimulation demonstrated clear, distinct responses regarding gene transcription rates as well as the time period needed for the effect to occur. Further, more integrative studies are required to associate functions to the evaluated genes more safely and better understand the triggering mechanisms.
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Affiliation(s)
- Rita Azeredo
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, 4450-208 Matosinhos, Portugal; (M.M.); (P.P.)
- Correspondence: (R.A.); (B.C.)
| | - Marina Machado
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, 4450-208 Matosinhos, Portugal; (M.M.); (P.P.)
| | - Patricia Pereiro
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, 4450-208 Matosinhos, Portugal; (M.M.); (P.P.)
- Instituto de Investigaciones Marinas (IIM-CSIC), 36208 Vigo, Spain
| | - Andre Barany
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cadiz, 11519 Puerto Real, Spain; (A.B.); (J.M.M.)
| | - Juan Miguel Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cadiz, 11519 Puerto Real, Spain; (A.B.); (J.M.M.)
| | - Benjamín Costas
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, 4450-208 Matosinhos, Portugal; (M.M.); (P.P.)
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS-UP), Universidade do Porto, 4050-313 Porto, Portugal
- Correspondence: (R.A.); (B.C.)
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do Carmo Silva RX, do Nascimento BG, Gomes GCV, da Silva NAH, Pinheiro JS, da Silva Chaves SN, Pimentel AFN, Costa BPD, Herculano AM, Lima-Maximino M, Maximino C. 5-HT2C agonists and antagonists block different components of behavioral responses to potential, distal, and proximal threat in zebrafish. Pharmacol Biochem Behav 2021; 210:173276. [PMID: 34555392 DOI: 10.1016/j.pbb.2021.173276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022]
Abstract
Serotonin (5-HT) receptors have been implicated in responses to aversive stimuli in mammals and fish, but its precise role is still unknown. Moreover, since at least seven families of 5-HT receptors exist in vertebrates, the role of specific receptors is still debated. Aversive stimuli can be classified as indicators of proximal, distal, or potential threat, initiating responses that are appropriate for each of these threat levels. Responses to potential threat usually involve cautious exploration and increased alertness, while responses to distal and proximal threat involve a fight-flight-freeze reaction. We exposed adult zebrafish to a conspecific alarm substance (CAS) and observed behavior during (distal threat) and after (potential threat) exposure, and treated with the 5-HT2C receptor agonists MK-212 or WAY-161503 or with the antagonist RS-102221. The agonists blocked CAS-elicited defensive behavior (distal threat), but not post-exposure increases in defensive behavior (potential threat), suggesting inhibition of responses to distal threat. MK-212 blocked changes in freezing elicited by acute restraint stress, a model of proximal threat, while RS-102221 blocked changes in geotaxis elicited this stressor. We also found that RS-102221, a 5-HT2C receptor antagonist, produced small effect on behavior during and after exposure to CAS. Preprint: https://www.biorxiv.org/content/10.1101/2020.10.04.324202; Data and scripts: https://github.com/lanec-unifesspa/5-HT-CAS/tree/master/data/5HT2C.
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Affiliation(s)
- Rhayra Xavier do Carmo Silva
- Laboratório de Neurofarmacologia Experimental - LNE, Universidade Federal do Pará, Belém/PA, Brazil; Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil
| | - Bianca Gomes do Nascimento
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil
| | - Gabriela Cristini Vidal Gomes
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil
| | | | - Jéssica Souza Pinheiro
- Laboratório de Neurofarmacologia Experimental - LNE, Universidade Federal do Pará, Belém/PA, Brazil
| | - Suianny Nayara da Silva Chaves
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil
| | - Ana Flávia Nogueira Pimentel
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil
| | - Bruna Patrícia Dutra Costa
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil
| | | | - Monica Lima-Maximino
- Laboratório de Neurofarmacologia e Biofísica - LaNeF, Universidade do Estado do Pará, Marabá/PA, Brazil
| | - Caio Maximino
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff" - LaNeC, Universidade Federal do Sul e Sudeste do Pará, Marabá/PA, Brazil.
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Shimon-Hophy M, Avtalion RR. Influence of chronic stress on the mechanism of the cytotoxic system in common carp (Cyprinus carpio). Immunology 2021; 164:211-222. [PMID: 33930181 PMCID: PMC8442244 DOI: 10.1111/imm.13345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022] Open
Abstract
Aquaculture conditions expose fish to internal and environmental stressors that increase their susceptibility to morbidity and mortality. The brain accumulates stress signals and processes them according to the intensity, frequency duration and type of stress, recruiting several brain functions to activate the autonomic or limbic system. Triggering the autonomic system causes the rapid release of catecholamines, such as adrenaline and noradrenaline, into circulation from chromaffin cells in the head kidney. Catecholamines trigger blood cells to release proinflammatory and regulatory cytokines to cope with acute stress. Activation of the limbic axis stimulates the dorsolateral and dorsomedial pallium to process emotions, memory, behaviour and the activation of preoptic nucleus‐pituitary gland‐interrenal cells in the head kidney, releasing glucocorticoids, such as cortisol to the bloodstream. Glucocorticoids cause downregulation of various immune system functions depending on the duration, intensity and type of chronic stress. As stress persists, most immune functions, with the exception of cytotoxic functions, overcome these effects and return to homeostasis. The deterioration of cytotoxic functions during chronic stress appears to be responsible for increased morbidity and mortality.
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Affiliation(s)
- Mazal Shimon-Hophy
- Laboratory of Comparative Immunology and Genetics, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Ramy R Avtalion
- Laboratory of Comparative Immunology and Genetics, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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Gerlach G, Wullimann MF. Neural pathways of olfactory kin imprinting and kin recognition in zebrafish. Cell Tissue Res 2021; 383:273-287. [PMID: 33515290 PMCID: PMC7873017 DOI: 10.1007/s00441-020-03378-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022]
Abstract
Teleost fish exhibit extraordinary cognitive skills that are comparable to those of mammals and birds. Kin recognition based on olfactory and visual imprinting requires neuronal circuits that were assumed to be necessarily dependent on the interaction of mammalian amygdala, hippocampus, and isocortex, the latter being a structure that teleost fish are lacking. We show that teleosts—beyond having a hippocampus and pallial amygdala homolog—also have subpallial amygdalar structures. In particular, we identify the medial amygdala and neural olfactory central circuits related to kin imprinting and kin recognition corresponding to an accessory olfactory system despite the absence of a separate vomeronasal organ.
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Affiliation(s)
- Gabriele Gerlach
- Institute of Biology and Environmental Sciences, Carl-von-Ossietzky University, 26129, Oldenburg, Germany.,Helmholtz Institute for Functional Marine Biodiversity Oldenburg (HIFMB), 26129, Oldenburg, Germany.,Centre of Excellence for Coral Reef Studies and School of Marine and Tropical Biology, James Cook University, QLD, 4811, Townsville, Australia
| | - Mario F Wullimann
- Graduate School of Systemic Neurosciences & Department Biology II, Ludwig-Maximilians-Universität Munich, 82152, Planegg-Martinsried, Germany. .,Max-Planck-Institute for Neurobiology, 82152, Planegg-Martinsried, Germany.
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Thangaleela S, Ragu Varman D, Sivasangari K, Rajan KE. Inhibition of monoamine oxidase attenuates social defeat-induced memory impairment in goldfish, (Carassius auratus): A possible involvement of synaptic proteins and BDNF. Comp Biochem Physiol C Toxicol Pharmacol 2021; 239:108873. [PMID: 32805442 DOI: 10.1016/j.cbpc.2020.108873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 01/12/2023]
Abstract
Social defeat (SD) has been implicated in different modulatory effects of physiology and behaviour including learning and memory. We designed an experiment to test the functional role of monoamine oxidase (MAO) in regulation of synaptic transmission, synaptic plasticity and memory in goldfish Carassius auratus. To test this, individuals were divided into three groups: (i) control; (ii) social defeat (SD) group (individuals were subjected to social defeat for 10 min by Pseudotropheus demasoni) and (iii) SD + MAO inhibitor pre-treated group. All experimental groups were subjected to spatial learning and then memory. Our results suggest that SD affects a spatial learning and memory, whereas SD exerts no influence on MAOI pre-treated group. In addition, we noted that the expression of monoamine oxidase-A (MAO-A) was up-regulated and level of serotonin (5-hydroxytryptamine; 5-HT), expression of serotonin transporter (SERT), synaptophysin (SYP), synaptotagmin -1 (SYT-1), N-methyl-D-asparate (NMDA) receptors subunits (NR2A and NR2B), postsynaptic density-95 (PSD-95) and brain-derived neurotrophic factor (BDNF) were reduced by SD, while MAOIs pretreatment protects the effect of SD. Taken together, our results suggest that MAO is an essential component in the serotonergic system that finely tunes the level of 5-HT, which further regulates the molecules involving in synaptic transmission, synaptic plasticity and memory.
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Affiliation(s)
- Subramanian Thangaleela
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, India
| | - Durairaj Ragu Varman
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, India; Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - Karunanithi Sivasangari
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, India
| | - Koilmani Emmanuvel Rajan
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, India.
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10
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Performance of cyprinids in non-reversing mirrors versus regular mirrors in tests of aggressiveness. J ETHOL 2020. [DOI: 10.1007/s10164-020-00679-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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11
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Liu ZH, Li YW, Hu W, Chen QL, Shen YJ. Mechanisms involved in tributyltin-enhanced aggressive behaviors and fear responses in male zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 220:105408. [PMID: 31935571 DOI: 10.1016/j.aquatox.2020.105408] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/03/2020] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
Tributyltin (TBT), an aromatase inhibitor, has been found to disrupt gametogenesis and reproductive behavior in several fish species. However, whether TBT is capable of affecting other behaviors such as aggressive behavior and fear response in fish and the underlying mode(s) of action remain unclear. To study aggressive behavior, adult zebrafish (Danio rerio) males were continuously exposed to two nominal concentrations of TBT (TBT-low, 100 ng/L and TBT-high, 500 ng/L) for 28 days. To study the fear response, the fish were divided into four groups (Blank and Control, 0 ng/L TBT; TBT-low, 100 ng/L; and TBT-high, 500 ng/L). The fish were then treated with DW (Blank) or with alarm substance (AS) (Control, TBT-low and TBT-high). After exposure, the aggressive behavior of the fish was tested using the mirror test (mirror-biting frequency, approaches to the mirror and duration in approach zone).and fighting test (fish-biting frequency) The mirror-biting frequency, approaches to the mirror, duration in approach zone and fish-biting frequency of the TBT-exposed fish increased significantly compared to those of the control fish, indicating enhanced aggressive behavior. The fear response parameters tested using the novel tank dive test (onset time to the higher half, total duration in the lower half and the frequency of turning) of the TBT-exposed fish were also significantly increased after AS administration, suggesting an enhanced fear response. Further investigation revealed that TBT treatment elevated the plasma level of 11-ketotestosterone (11-KT) and decreased the plasma level of estradiol (E2) in a concentration-dependent manner. Moreover, TBT up-regulated the mRNA levels of ar, c-fos and bdnf1, and suppressed the expression of btg-2 in fish. In addition, exposure to AS increased the plasma level of cortisol and down-regulated the mRNA expression levels of genes involved in 5-HT synthesis (such as tph1b and pet1) in both control and TBT-treated fish. AS significantly suppressed the mRNA level of tph1b, tph2, pet1 and npy in the TBT-high group compared to the control fish. The present study demonstrates that TBT enhances aggressive behavior and fear responses in male zebrafish probably through altering plasma levels of 11-KT, E2 and cortisol and altering the expression of genes involved in the regulation of aggressive behavior (ar, c-fos, bdnf1 and btg-2) and fear responses (tph1b, tph2, pet1 and npy). The present study greatly extends our understanding of the behavioral toxicity of TBT to fish.
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Affiliation(s)
- Zhi-Hao Liu
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China.
| | - Ying-Wen Li
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Wei Hu
- Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Qi-Liang Chen
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
| | - Yan-Jun Shen
- Chongqing Key Laboratory of Animal Biology, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
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12
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Höglund E, Korzan W, Åtland Å, Haraldstad T, Høgberget R, Mayer I, Øverli Ø. Neuroendocrine indicators of allostatic load reveal the impact of environmental acidification in fish. Comp Biochem Physiol C Toxicol Pharmacol 2020; 229:108679. [PMID: 31794875 DOI: 10.1016/j.cbpc.2019.108679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/11/2019] [Accepted: 11/28/2019] [Indexed: 01/19/2023]
Abstract
When mobilized from surrounding soils and binding to gills at moderately low pH, aluminum (Al) cations can adversely affect fish populations. Furthermore, acidification may lead to allostatic overload, a situation in which the costs of coping with chronic stress affects long-term survival and reproductive output and, ultimately, ecosystem health. The brain's serotonergic system plays a key role in neuroendocrine stress responses and allostatic processes. Here, we explored whether sublethal effects of Al in acidified water affects serotonergic neurochemistry and stress coping ability in a unique land-locked salmon population from Lake Bygelandsfjorden, in southern Norway. Fish were exposed to untreated water with pH 6.5 and 74 μg Al l-1 or acidified (pH 5.5) water with different aluminum concentrations ([Al]; 74-148 μg l-1) for 5-6 days. Afterward, effects on stress coping ability were investigated by analyzing plasma cortisol levels and telencephalic serotonergic neurochemistry before and after a standardized acute stress test. Before the stress test, positive dose-response relationships existed between [Al], serotonergic turnover rate and plasma cortisol. However, in acutely stressed fish, exposure to the highest [Al] resulted in reduced cortisol values compared with those exposed to lower concentrations, while the positive dose-response relationship between Al concentrations and serotonergic turnover rate persisted in baseline conditions. This suggests that fish exposed to the highest Al concentration were unable to mount a proper cortisol response to further acute stress, demonstrating that neuroendocrine indicators of allostatic load can be used to reveal sublethal effects of water acidification-and potentially, the environmental impacts of other factors.
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Affiliation(s)
- Erik Höglund
- Niva, Norsk institutt for vannforskning, Gaustadalléen 21, NO-0349 Oslo, Norway; Center of Coastal Research, University of Agder, 4604 Kristiansand, Norway.
| | - Wayne Korzan
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Åse Åtland
- Niva, Norsk institutt for vannforskning, Gaustadalléen 21, NO-0349 Oslo, Norway
| | - Tormod Haraldstad
- Niva, Norsk institutt for vannforskning, Gaustadalléen 21, NO-0349 Oslo, Norway
| | - Rolf Høgberget
- Niva, Norsk institutt for vannforskning, Gaustadalléen 21, NO-0349 Oslo, Norway
| | - Ian Mayer
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, 0454 Oslo, Norway
| | - Øyvind Øverli
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, 0454 Oslo, Norway
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13
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Contrasting neurochemical and behavioral profiles reflects stress coping styles but not stress responsiveness in farmed gilthead seabream (Sparus aurata). Physiol Behav 2020; 214:112759. [PMID: 31785269 DOI: 10.1016/j.physbeh.2019.112759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 11/22/2022]
Abstract
In fish, as well as in other vertebrates, contrasting suites of physiological and behavioral traits, or coping styles, are often shown in response to stressors. However, the magnitude of the response (i.e. stress responsiveness) has been suggested to be independent of stress coping style. One central neurotransmitter that has been associated with both stress responsiveness and differences in stress coping styles is serotonin (5-hydroxytryptamine, 5-HT). In this study, we investigated to what extent stress responsiveness reflects differences in stress coping, and the potential involvement of the 5-HT system in mediating such differences in farmed Gilthead seabream. Initially, fish were classified as proactive or reactive based on their behavioural response to net restraint. Following 1.5 months, fish classified as proactive still showed a higher number of escape attempts and spent longer time escaping than those classified as reactive. These differences were reflected in a generally higher brain stem 5-HT concentration and a lower telencephalic 5-HT activity, i.e. the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT, in proactive fish. Independent of stress coping styles, stress responsiveness was reflected in elevated 5-HIAA concentrations and 5-HIAA/5-HT ratios in telencephalon and brain stem together with increased plasma cortisol concentrations at 0.5 and 2 h following the last net restraint. The current results show that 5-HT signaling can reflect different behavioural output to a challenge which are independent of neuroendocrine responses to stress and lend support to the hypothesis that stress coping styles can be independent of stress responsiveness.
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14
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Ferrari S, Rey S, Høglund E, Øverli Ø, Chatain B, MacKenzie S, Bégout ML. Physiological responses during acute stress recovery depend on stress coping style in European sea bass, Dicentrarchus labrax. Physiol Behav 2020; 216:112801. [PMID: 31931036 DOI: 10.1016/j.physbeh.2020.112801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 12/12/2019] [Accepted: 01/07/2020] [Indexed: 02/08/2023]
Abstract
Individual stress coping style (reactive, intermediate and proactive) was determined in 3 groups of 120 pit tagged European seabass using the hypoxia avoidance test. The same three groups (no change in social composition) were then reared according to the standards recommended for this species. Then, 127 days later, individuals initially characterized as reactive, intermediate or proactive were submitted to an acute confinement stress for 30 min. Blood samples were taken to measure plasma cortisol levels 30 min (Stress30) or 150 min (Stress150) after the end of the confinement stress. Individuals were then sacrificed to sample the telencephalon in order to measure the main monoamines and their catabolites (at Stress30 only). Individuals from Stress150 were sampled for whole brain for a transcriptomic analysis. The main results showed that reactive individuals had a lower body mass than intermediate individuals which did not differ from proactive individuals. The physiological cortisol response did not differ between coping style at Stress30 but at Stress150 when intermediate and proactive individuals had recovered pre stress levels, reactive individuals showed a significant higher level illustrating a modulation of stress recovery by coping style. Serotonin turnover ratio was higher in proactive and reactive individuals compared to intermediate individuals and a significant positive correlation was observed with cortisol levels whatever the coping style. Further, the confinement stress led to a general increase in the serotonin turnover comparable between coping styles. Stress150 had a significant effect on target mRNA copy number (Gapdh mRNA copy number decreased while ifrd1 mRNA copy number increased) and such changes tended to depend upon coping style.
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Affiliation(s)
- Sébastien Ferrari
- Ifremer, Fisheries Research Laboratory, L'Houmeau 17137, France; MARBEC, Ifremer, Université de Montpellier, CNRS, IRD, Palavas-les-flots, France
| | - Sonia Rey
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK
| | - Erik Høglund
- Norwegian Institute for Water Research (NIVA), Oslo N-0349, Norway
| | - Øyvind Øverli
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo N-0033, Norway
| | - Béatrice Chatain
- MARBEC, Ifremer, Université de Montpellier, CNRS, IRD, Palavas-les-flots, France
| | - Simon MacKenzie
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK
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15
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Johansen IB, Höglund E, Øverli Ø. Individual Variations and Coping Style. Anim Welf 2020. [DOI: 10.1007/978-3-030-41675-1_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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16
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Maximino C, do Carmo Silva RX, Dos Santos Campos K, de Oliveira JS, Rocha SP, Pyterson MP, Dos Santos Souza DP, Feitosa LM, Ikeda SR, Pimentel AFN, Ramos PNF, Costa BPD, Herculano AM, Rosemberg DB, Siqueira-Silva DH, Lima-Maximino M. Sensory ecology of ostariophysan alarm substances. JOURNAL OF FISH BIOLOGY 2019; 95:274-286. [PMID: 30345536 DOI: 10.1111/jfb.13844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 10/12/2018] [Indexed: 06/08/2023]
Abstract
Chemical communication of predation risk has evolved multiple times in fish species, with conspecific alarm substance (CAS) being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish are captured by a predator and elicits neurobehavioural adjustments in conspecifics which increase the probability of avoiding predation. As such, CAS is a partial predator stimulus, eliciting risk assessment-like and avoidance behaviours and disrupting the predation sequence. The present paper reviews the distribution and putative composition of CAS in fish and presents a model for the neural processing of these structures by the olfactory and the brain aversive systems. Applications of CAS in the behavioural neurosciences and neuropharmacology are also presented, exploiting the potential of model fish [e.g., zebrafish Danio rerio, guppies Poecilia reticulata, minnows Phoxinus phoxinus) in neurobehavioural research.
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Affiliation(s)
- Caio Maximino
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
| | - Rhayra X do Carmo Silva
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
- Programa de Pós-Graduação em Neurociências e Biologia Celular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Kimberly Dos Santos Campos
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
| | - Jeisiane S de Oliveira
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
| | - Sueslene P Rocha
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
| | - Maryana P Pyterson
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
| | - Dainara P Dos Santos Souza
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
| | - Leonardo M Feitosa
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
| | - Saulo R Ikeda
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
| | - Ana F N Pimentel
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
| | - Pâmila N F Ramos
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
- Rede de Biodiversidade e Biotecnologia da Amazônia Legal, Universidade Estadual do Maranhão - Cidade Universitária Paulo VI - Predio da Veterinária, São Luis, Brazil
| | - Bruna P D Costa
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
- Rede de Biodiversidade e Biotecnologia da Amazônia Legal, Universidade Estadual do Maranhão - Cidade Universitária Paulo VI - Predio da Veterinária, São Luis, Brazil
| | - Anderson M Herculano
- Laboratório de Neurofarmacologia Experimental, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Denis B Rosemberg
- Laboratório de Neuropsicobiologia Experimental, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Diógenes H Siqueira-Silva
- Laboratório de Neurociências e Comportamento "Frederico Guilherme Graeff", Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Nova Marabá, Brazil
| | - Monica Lima-Maximino
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII/Marabá, Marabá, Brazil
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17
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do Carmo Silva RX, Lima-Maximino MG, Maximino C. The aversive brain system of teleosts: Implications for neuroscience and biological psychiatry. Neurosci Biobehav Rev 2018; 95:123-135. [DOI: 10.1016/j.neubiorev.2018.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 10/03/2018] [Accepted: 10/04/2018] [Indexed: 12/24/2022]
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18
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Early life stress induces long-term changes in limbic areas of a teleost fish: the role of catecholamine systems in stress coping. Sci Rep 2018; 8:5638. [PMID: 29618742 PMCID: PMC5884775 DOI: 10.1038/s41598-018-23950-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/20/2018] [Indexed: 01/05/2023] Open
Abstract
Early life stress (ELS) shapes the way individuals cope with future situations. Animals use cognitive flexibility to cope with their ever-changing environment and this is mainly processed in forebrain areas. We investigated the performance of juvenile gilthead seabream, previously subjected to an ELS regime. ELS fish showed overall higher brain catecholaminergic (CA) signalling and lower brain derived neurotrophic factor (bdnf) and higher cfos expression in region-specific areas. All fish showed a normal cortisol and serotonergic response to acute stress. Brain dopaminergic activity and the expression of the α2Α adrenergic receptor were overall higher in the fish homologue to the lateral septum (Vv), suggesting that the Vv is important in CA system regulation. Interestingly, ELS prevented post-acute stress downregulation of the α2Α receptor in the amygdala homologue (Dm3). There was a lack of post-stress response in the β2 adrenergic receptor expression and a downregulation in bdnf in the Dm3 of ELS fish, which together indicate an allostatic overload in their stress coping ability. ELS fish showed higher neuronal activity (cfos) post-acute stress in the hippocampus homologue (Dlv) and the Dm3. Our results show clear long-term effects on limbic systems of seabream that may compromise their future coping ability to environmental challenges.
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Abstract
Comparative models suggest that effects of dietary tryptophan (Trp) on brain serotonin (5-hydroxytryptamine; 5-HT) neurochemistry and stress responsiveness are present throughout the vertebrate lineage. Moreover, hypothalamic 5-HT seems to play a central role in control of the neuroendocrine stress axis in all vertebrates. Still, recent fish studies suggest long-term effects of dietary Trp on stress responsiveness, which are independent of hypothalamic 5-HT. Here, we investigated if dietary Trp treatment may result in long-lasting effects on stress responsiveness, including changes in plasma cortisol levels and 5-HT neurochemistry in the telencephalon and hypothalamus of Atlantic salmon. Fish were fed diets containing one, two or three times the Trp content in normal feed for 1 week. Subsequently, fish were reintroduced to control feed and were exposed to acute crowding stress for 1 h, 8 and 21 d post Trp treatment. Generally, acute crowding resulted in lower plasma cortisol levels in fish treated with 3×Trp compared with 1×Trp- and 2×Trp-treated fish. The same general pattern was reflected in telencephalic 5-HTergic turnover, for which 3×Trp-treated fish showed decreased values compared with 2×Trp-treated fish. These long-term effects on post-stress plasma cortisol levels and concomitant 5-HT turnover in the telencephalon lends further support to the fact that the extrahypothalamic control of the neuroendocrine stress response is conserved within the vertebrate lineage. Moreover, they indicate that trophic/structural effects in the brain underlie the effects of dietary Trp treatment on stress reactivity.
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20
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Abreu MS, Giacomini ACVV, Koakoski G, Piato ALS, Barcellos LJG. Divergent effect of fluoxetine on the response to physical or chemical stressors in zebrafish. PeerJ 2017; 5:e3330. [PMID: 28503384 PMCID: PMC5426348 DOI: 10.7717/peerj.3330] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/18/2017] [Indexed: 12/19/2022] Open
Abstract
Fluoxetine is a selective serotonin reuptake inhibitor that increases serotonin concentration in the central nervous system and modulates various systems, including the control of sympathetic outflow and the hypothalamus–pituitary–adrenal. However, it is not yet established whether fluoxetine can modulate the responses to stressors stimulants (physical or chemical) that trigger cortisol response in zebrafish. We demonstrate that fluoxetine blunts the response to physical stress, but not to chemical stress.
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Affiliation(s)
- Murilo S Abreu
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Ana Cristina V V Giacomini
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.,Universidade de Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
| | - Gessi Koakoski
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Angelo L S Piato
- Programa de Pós-Graduação em Farmacologia e Terapêutica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Leonardo J G Barcellos
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.,Programa de Pós-Graduação em Bioexperimentação, Universidade de Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
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21
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Cannabinoid modulation of zebrafish fear learning and its functional analysis investigated by c-Fos expression. Pharmacol Biochem Behav 2016; 153:18-31. [PMID: 27965084 DOI: 10.1016/j.pbb.2016.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/05/2016] [Accepted: 12/09/2016] [Indexed: 12/31/2022]
Abstract
It has been shown that zebrafish fear learning proceeds in the same way as reported for rodents. However, in zebrafish fear learning it is possible to substitute the use of electric shocks as unconditioned stimulus and utilize the inborn fear responses to the alarm substance Schreckstoff, instead. The skin extract Schreckstoff elicits typical fear reactions such as preferred bottom dwelling, swimming in a tighter shoal, erratic movements and freezing. This natural fear behavior can be transferred from Schreckstoff to any other sensory stimulus by associative conditioning (fear learning). We presented Schreckstoff simultaneously with a red light stimulus and tested the effectiveness of fear learning during memory retrieval. The two brain regions known to be relevant for learning in zebrafish are the medial and the lateral pallium of the dorsal telencephalon, both containing rich expressions of the endocannabinoid receptor CB1. To test the influence of the zebrafish endocannabinoid system on fear acquisition learning, an experimental group of ten fish was pretreated with the CB1 receptor agonist THC (Δ9-tetrahydrocannabinol; 100nM for 1h). We found that CB1 activation significantly inhibited acquisition of fear learning, possibly by impairing stimulus encoding processes in pallial areas. This was supported by analyzes of c-Fos expression in the brains of experimental animals. Schreckstoff exposure during fear acquisition learning and memory retrieval during red light presentation increased the number of labelled cells in pallial structures, but in no other brain region investigated (e.g. striatum, thalamus, and habenula). THC administration before fear conditioning significantly decreased c-Fos expression in these structures to a level similar to the control group without Schreckstoff experience, suggesting that Schreckstoff induced fear learning requires brain circuits restricted mainly to pallial regions of the dorsal telencephalon.
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22
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Moltesen M, Laursen DC, Thörnqvist PO, Andersson MÅ, Winberg S, Höglund E. Effects of acute and chronic stress on telencephalic neurochemistry and gene expression in rainbow trout (Oncorhynchus mykiss). ACTA ACUST UNITED AC 2016; 219:3907-3914. [PMID: 27802140 DOI: 10.1242/jeb.139857] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 10/03/2016] [Indexed: 12/16/2022]
Abstract
By filtering relevant sensory inputs and initiating stress responses, the brain is an essential organ in stress coping and adaptation. However, exposure to chronic or repeated stress can lead to allostatic overload, where neuroendocrinal and behavioral reactions to stress become maladaptive. This work examines forebrain mechanisms involved in allostatic processes in teleost fishes. Plasma cortisol, forebrain serotonergic (5-HTergic) neurochemistry, and mRNA levels of corticotropin-releasing factor (CRF), CRF-binding protein (CRF-BP), CRF receptors (CRFR1 and CRFR2), mineralocorticoid receptor (MR), glucocorticoid receptors (GR1 and GR2) and serotonin type 1A (5-HT1A) receptors (5-HT1Aα and 5-HT1Aβ) were investigated at 1 h before and 0, 1 and 4 h after acute stress, in two groups of rainbow trout held in densities of 25 and 140 kg m-3 for 28 days. Generally, being held at 140 kg m-3 resulted in a less pronounced cortisol response. This effect was also reflected in lower forebrain 5-HTergic turnover, but not in mRNA levels in any of the investigated genes. This lends further support to reports that allostatic load causes fish to be incapable of mounting a proper cortisol response to an acute stressor, and suggests that changes in forebrain 5-HT metabolism are involved in allostatic processes in fish. Independent of rearing densities, mRNA levels of 5-HT1Aα and MR were downregulated 4 h post-stress compared with values 1 h post-stress, suggesting that these receptors are under feedback control and take part in the downregulation of the hypothalamic-pituitary-interrenal (HPI) axis after exposure to an acute stressor.
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Affiliation(s)
- Maria Moltesen
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, Building 3, 4th Floor, Copenhagen Ø DK-2100, Denmark.,Section for Aquaculture, Institute for Aquatic Resources, Danish Technical University, P.O. Box 101, Hirtshals DK-9850, Denmark
| | - Danielle Caroline Laursen
- Section for Aquaculture, Institute for Aquatic Resources, Danish Technical University, P.O. Box 101, Hirtshals DK-9850, Denmark
| | - Per-Ove Thörnqvist
- Department of Neuroscience, Uppsala University, P.O. Box 593, Uppsala SE-75124, Sweden
| | - Madelene Åberg Andersson
- Chemical Biology and Therapeutics, Department of Experimental Medical Science, Lund University, P.O. Box 188, Lund SE-22100, Sweden
| | - Svante Winberg
- Department of Neuroscience, Uppsala University, P.O. Box 593, Uppsala SE-75124, Sweden
| | - Erik Höglund
- Section for Aquaculture, Institute for Aquatic Resources, Danish Technical University, P.O. Box 101, Hirtshals DK-9850, Denmark .,Norwegian Institute for Water Research, NIVA, Gaustadalléen 21NO-0349, Oslo, Norway
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23
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Vindas MA, Madaro A, Fraser TWK, Höglund E, Olsen RE, Øverli Ø, Kristiansen TS. Coping with a changing environment: the effects of early life stress. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160382. [PMID: 27853554 PMCID: PMC5098979 DOI: 10.1098/rsos.160382] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/01/2016] [Indexed: 05/13/2023]
Abstract
Ongoing rapid domestication of Atlantic salmon implies that individuals are subjected to evolutionarily novel stressors encountered under conditions of artificial rearing, requiring new levels and directions of flexibility in physiological and behavioural coping mechanisms. Phenotypic plasticity to environmental changes is particularly evident at early life stages. We investigated the performance of salmon, previously subjected to an unpredictable chronic stress (UCS) treatment at an early age (10 month old parr), over several months and life stages. The UCS fish showed overall higher specific growth rates compared with unstressed controls after smoltification, a particularly challenging life stage, and after seawater transfer. Furthermore, subjecting fish to acute stress at the end of the experiment, we found that UCS groups had an overall lower hypothalamic catecholaminergic and brain stem serotonergic response to stress compared with control groups. In addition, serotonergic activity was negatively correlated with final growth rates, which implies that serotonin responsive individuals have growth disadvantages. Altogether, our results may imply that a subdued monoaminergic response in stressful farming environments may be beneficial, because in such situations individuals may be able to reallocate energy from stress responses into other life processes, such as growth.
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Affiliation(s)
- Marco A. Vindas
- Uni Environment, Uni Research AS, Bergen, Norway
- Department of Biosciences, University of Oslo, Oslo, Norway
- Author for correspondence: Marco A. Vindas e-mail:
| | | | - Thomas W. K. Fraser
- Department of Production Animal and Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Erik Höglund
- National Institute of Aquatic Resources, Technical University of Denmark, Hirtshals, Denmark
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
| | - Rolf E. Olsen
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Øyvind Øverli
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
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24
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Rey S, Huntingford FA, Boltaña S, Vargas R, Knowles TG, Mackenzie S. Fish can show emotional fever: stress-induced hyperthermia in zebrafish. Proc Biol Sci 2016; 282:rspb.2015.2266. [PMID: 26609087 PMCID: PMC4685827 DOI: 10.1098/rspb.2015.2266] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Whether fishes are sentient beings remains an unresolved and controversial question. Among characteristics thought to reflect a low level of sentience in fishes is an inability to show stress-induced hyperthermia (SIH), a transient rise in body temperature shown in response to a variety of stressors. This is a real fever response, so is often referred to as ‘emotional fever’. It has been suggested that the capacity for emotional fever evolved only in amniotes (mammals, birds and reptiles), in association with the evolution of consciousness in these groups. According to this view, lack of emotional fever in fishes reflects a lack of consciousness. We report here on a study in which six zebrafish groups with access to a temperature gradient were either left as undisturbed controls or subjected to a short period of confinement. The results were striking: compared to controls, stressed zebrafish spent significantly more time at higher temperatures, achieving an estimated rise in body temperature of about 2–4°C. Thus, zebrafish clearly have the capacity to show emotional fever. While the link between emotion and consciousness is still debated, this finding removes a key argument for lack of consciousness in fishes.
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Affiliation(s)
- Sonia Rey
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Felicity A Huntingford
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Sebastian Boltaña
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Reynaldo Vargas
- Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Toby G Knowles
- School of Veterinary Science, University of Bristol, Langford, Bristol BS40 5DU, UK
| | - Simon Mackenzie
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
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25
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Dunlap KD, Tran A, Ragazzi MA, Krahe R, Salazar VL. Predators inhibit brain cell proliferation in natural populations of electric fish, Brachyhypopomus occidentalis. Proc Biol Sci 2016; 283:20152113. [PMID: 26842566 PMCID: PMC4760157 DOI: 10.1098/rspb.2015.2113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/08/2016] [Indexed: 11/12/2022] Open
Abstract
Compared with laboratory environments, complex natural environments promote brain cell proliferation and neurogenesis. Predators are one important feature of many natural environments, but, in the laboratory, predatory stimuli tend to inhibit brain cell proliferation. Often, laboratory predatory stimuli also elevate plasma glucocorticoids, which can then reduce brain cell proliferation. However, it is unknown how natural predators affect cell proliferation or whether glucocorticoids mediate the neurogenic response to natural predators. We examined brain cell proliferation in six populations of the electric fish, Brachyhypopomus occidentalis, exposed to three forms of predator stimuli: (i) natural variation in the density of predatory catfish; (ii) tail injury, presumably from predation attempts; and (iii) the acute stress of capture. Populations with higher predation pressure had lower density of proliferating (PCNA+) cells, and fish with injured tails had lower proliferating cell density than those with intact tails. However, plasma cortisol did not vary at the population level according to predation pressure or at the individual level according to tail injury. Capture stress significantly increased cortisol, but only marginally decreased cell proliferation. Thus, it appears that the presence of natural predators inhibits brain cell proliferation, but not via mechanisms that depend on changes in basal cortisol levels. This study is the first demonstration of predator-induced alteration of brain cell proliferation in a free-living vertebrate.
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Affiliation(s)
- Kent D Dunlap
- Department of Biology, Trinity College, Hartford, CT 06106, USA
| | - Alex Tran
- Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1
| | | | - Rüdiger Krahe
- Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1
| | - Vielka L Salazar
- Department of Biology, Cape Breton University, Sydney, Nova Scotia, Canada B1P 6L2
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26
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Moltesen M, Vindas MA, Winberg S, Ebbesson L, de Lourdes Ruiz-Gomez M, Skov PV, Dabelsteen T, Øverli Ø, Höglund E. Cognitive appraisal of aversive stimulus differs between individuals with contrasting stress coping styles; evidences from selected rainbow trout (Oncorhynchus mykiss) strains. BEHAVIOUR 2016. [DOI: 10.1163/1568539x-00003405] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In animals, personality variations in response to stress and energy demands have been established. Cognitive processing of negative stimuli correlates with stress response patterns. Still, the relative contribution of cognitive appraisal or physiological demands to the behavioural output needs to be clarified. In this study we utilized reactive (high-responsive, HR) and proactive (low-responsive, LR) rainbow trout strains to investigate how contrasting reactions to hypoxia are related to individual variation in metabolism and/or cognition. The HR-LR strains did not differ in standard metabolic rate or hypoxia tolerance. HR trout displayed more pronounced avoidance to a signal cue after being conditioned with hypoxia, suggesting that they experienced this stimulus more aversive than LR trout. Together with differences in forebrain c-fos activation patterns in dorsomedial pallium, these results suggest cognitive differences between the strains. These results demonstrate that differences in personality/stress coping style can be related to contrasts in cognition, which are independent of metabolic differences.
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Affiliation(s)
- Maria Moltesen
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, building 3, 4th floor, DK-2100 Copenhagen Ø, Denmark
- Section for Aquaculture, Institute for Aquatic Resources, Danish Technical University, P.O. Box 101, DK-9850 Hirtshals, Denmark
| | - Marco Antonio Vindas
- Integrative Fish Biology, Uni Research Environment, Uni Research, P.O. Box 7803, NO-5020 Bergen, Norway
| | - Svante Winberg
- Department of Neuroscience, Uppsala University, P.O. Box 593, SE-75124 Uppsala, Sweden
| | - Lars Ebbesson
- Integrative Fish Biology, Uni Research Environment, Uni Research, P.O. Box 7803, NO-5020 Bergen, Norway
| | - Maria de Lourdes Ruiz-Gomez
- Facultad de Ciencias, Universidad Autónoma del Estado de Mexico, Instituto Literario Numero 100 Centro, Toluca, C.P. 50000, Mexico
| | - Peter Vilhelm Skov
- Section for Aquaculture, Institute for Aquatic Resources, Danish Technical University, P.O. Box 101, DK-9850 Hirtshals, Denmark
| | - Torben Dabelsteen
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, building 3, 4th floor, DK-2100 Copenhagen Ø, Denmark
| | - Øyvind Øverli
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway
| | - Erik Höglund
- Section for Aquaculture, Institute for Aquatic Resources, Danish Technical University, P.O. Box 101, DK-9850 Hirtshals, Denmark
- Niva Region South, Norsk institutt for vannforskning, Gaustadalléen 21, NO-0349 Oslo, Norway
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27
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Carr JA. I'll take the low road: the evolutionary underpinnings of visually triggered fear. Front Neurosci 2015; 9:414. [PMID: 26578871 PMCID: PMC4624861 DOI: 10.3389/fnins.2015.00414] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/15/2015] [Indexed: 11/16/2022] Open
Abstract
Although there is general agreement that the central nucleus of the amygdala (CeA) is critical for triggering the neuroendocrine response to visual threats, there is uncertainty about the role of subcortical visual pathways in this process. Primates in general appear to depend less on subcortical visual pathways than other mammals. Yet, imaging studies continue to indicate a role for the superior colliculus and pulvinar nucleus in fear activation, despite disconnects in how these brain structures communicate not only with each other but with the amygdala. Studies in fish and amphibians suggest that the neuroendocrine response to visual threats has remained relatively unchanged for hundreds of millions of years, yet there are still significant data gaps with respect to how visual information is relayed to telencephalic areas homologous to the CeA, particularly in fish. In fact ray finned fishes may have evolved an entirely different mechanism for relaying visual information to the telencephalon. In part because they lack a pathway homologous to the lateral geniculate-striate cortex pathway of mammals, amphibians continue to be an excellent model for studying how stress hormones in turn modulate fear activating visual pathways. Glucocorticoids, melanocortin peptides, and CRF all appear to play some role in modulating sensorimotor processing in the optic tectum. These observations, coupled with data showing control of the hypothalamus-pituitary-adrenal axis by the superior colliculus, suggest a fear/stress/anxiety neuroendocrine circuit that begins with first order synapses in subcortical visual pathways. Thus, comparative studies shed light not only on how fear triggering visual pathways came to be, but how hormones released as a result of this activation modulate these pathways.
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Affiliation(s)
- James A. Carr
- Department of Biological Sciences, Texas Tech UniversityLubbock, TX, USA
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