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Graf A, Murray SH, Eltahir A, Patel S, Hansson AC, Spanagel R, McCormick CM. Acute and long-term sex-dependent effects of social instability stress on anxiety-like and social behaviours in Wistar rats. Behav Brain Res 2023; 438:114180. [PMID: 36349601 DOI: 10.1016/j.bbr.2022.114180] [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: 07/29/2022] [Revised: 10/07/2022] [Accepted: 10/25/2022] [Indexed: 11/02/2022]
Abstract
Adolescence is a critical time of social learning in which both the quantity and quality of social interactions shape adult behavior and social function. During adolescence, social instability such as disrupting or limiting social interactions can lead to negative life-long effects on mental health and well-being in humans. Animal models on social instability are critically important in understanding those underlying neurobiological mechanisms. However, studies in rats using these models have produced partly inconsistent results and can be difficult to generalize. Here we assessed in a sex and age consistent manner the long-term behavioural consequences of social instability stress (SIS - 1-hr daily isolation and change in cage mate between postnatal day (PD30-45)) in Wistar rats. Female and male rats underwent a battery of tests for anxiety-like, exploratory, and social behaviour over five days beginning either in adolescence (PD46) or in adulthood (PD70). Social instability led to reduced anxiety-like behaviour in the elevated plus maze in both sexes in adolescence and in adulthood. Social interactions were also reduced in rats that underwent SIS - an effect that was independent of sex and age when tested. SIS improved social recognition memory in both sexes whereas a sex-dependent effect was seen in the social novelty preference test where male rats that underwent SIS spent more time in social approach toward a novel peer than toward their cage mate. In comparison, control male and female groups did not differ in this test, in time spent with novel versus the cage mate. Thus, overall, social instability stress in Wistar rats altered the behavioural repertoire, with enduring alterations in social behaviour, enhanced exploratory behaviour, and reduced anxiety-like behaviour. In conclusion, the social instability stress paradigm may better be interpreted as a form of enrichment in Wistar rats than as a stressor.
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Affiliation(s)
- Akseli Graf
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Shealin H Murray
- Centre for Neuroscience and Department of Psychology, Brock University, St. Catharines, Canada
| | - Akif Eltahir
- Centre for Neuroscience and Department of Psychology, Brock University, St. Catharines, Canada
| | - Smit Patel
- Centre for Neuroscience and Department of Psychology, Brock University, St. Catharines, Canada
| | - Anita C Hansson
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Cheryl M McCormick
- Centre for Neuroscience and Department of Psychology, Brock University, St. Catharines, Canada.
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2
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Koert A, Ploeger A, Bockting CL, Schmidt MV, Lucassen PJ, Schrantee A, Mul JD. The social instability stress paradigm in rat and mouse: A systematic review of protocols, limitations, and recommendations. Neurobiol Stress 2021; 15:100410. [PMID: 34926732 PMCID: PMC8648958 DOI: 10.1016/j.ynstr.2021.100410] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/27/2021] [Accepted: 10/15/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Social stress is an important environmental risk factor for the development of psychiatric disorders, including depression and anxiety disorders. Social stress paradigms are commonly used in rats and mice to gain insight into the pathogenesis of these disorders. The social instability stress (SIS) paradigm entails frequent (up to several times a week) introduction of one or multiple unfamiliar same-sex home-cage partners. The subsequent recurring formation of a new social hierarchy results in chronic and unpredictable physical and social stress. PURPOSE We compare and discuss the stress-related behavioral and physiological impact of SIS protocols in rat and mouse, and address limitations due to protocol variability. We further provide practical recommendations to optimize reproducibility of SIS protocols. METHODS We conducted a systematic review in accordance with the PRISMA statement in the following three databases: PubMed, Web of Science and Scopus. Our search strategy was not restricted to year of publication but was limited to articles in English that were published in peer-reviewed journals. Search terms included "social* instab*" AND ("animal" OR "rodent" OR "rat*" OR "mice" OR "mouse"). RESULTS Thirty-three studies met our inclusion criteria. Fifteen articles used a SIS protocol in which the composition of two cage mates is altered daily for sixteen days (SIS16D). Eleven articles used a SIS protocol in which the composition of four cage mates is altered twice per week for 49 days (SIS49D). The remaining seven studies used SIS protocols that differed from these two protocols in experiment duration or cage mate quantity. Behavioral impact of SIS was primarily assessed by quantifying depressive-like, anxiety-like, social-, and cognitive behavior. Physiological impact of SIS was primarily assessed using metabolic parameters, hypothalamus-pituitary-adrenal axis activity, and the assessment of neurobiological parameters such as neuroplasticity and neurogenesis. CONCLUSION Both shorter and longer SIS protocols induce a wide range of stress-related behavioral and physiological impairments that are relevant for the pathophysiology of depression and anxiety disorders. To date, SIS16D has only been reported in rats, whereas SIS49D has only been reported in mice. Given this species-specific application as well as variability in reported SIS protocols, additional studies should determine whether SIS effects are protocol duration- or species-specific. We address several issues, including a lack of consistency in the used SIS protocols, and suggest practical, concrete improvements in design and reporting of SIS protocols to increase standardization and reproducibility of this etiologically relevant preclinical model of social stress.
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Affiliation(s)
- Amber Koert
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Amsterdam, the Netherlands
- Centre for Urban Mental Health, University of Amsterdam, Amsterdam, the Netherlands
| | - Annemie Ploeger
- Department of Psychology, University of Amsterdam, Amsterdam, the Netherlands
| | - Claudi L.H. Bockting
- Centre for Urban Mental Health, University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Psychiatry, Amsterdam, the Netherlands
| | - Mathias V. Schmidt
- Max Planck Institute of Psychiatry, Research Group Neurobiology of Stress Resilience, Munich, Germany
| | - Paul J. Lucassen
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Amsterdam, the Netherlands
- Centre for Urban Mental Health, University of Amsterdam, Amsterdam, the Netherlands
| | - Anouk Schrantee
- Centre for Urban Mental Health, University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Radiology and Nuclear Medicine, Amsterdam, the Netherlands
| | - Joram D. Mul
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Amsterdam, the Netherlands
- Centre for Urban Mental Health, University of Amsterdam, Amsterdam, the Netherlands
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3
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Ebensperger LA, Gómez C, Aspillaga-Cid A, León C, Ramírez-Estrada J, Correa LA, Vera DC, Abades S, Hayes LD. Socially unstable conditions experienced during development prime female Octodon degus to shape the phenotype of their own offspring. Horm Behav 2021; 134:105011. [PMID: 34130042 DOI: 10.1016/j.yhbeh.2021.105011] [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: 01/22/2021] [Revised: 05/29/2021] [Accepted: 05/31/2021] [Indexed: 11/15/2022]
Abstract
Because residents and immigrants from group living species may experience fitness costs associated with permanent changes in group membership, we examined the hypothesis that females experiencing socially unstable or socially stable conditions during development compensate these costs by shaping the phenotype of their own offspring differently. Groups of adult females experiencing either socially stable or unstable conditions in the early social environment were assigned to either socially stable or unstable conditions in the social environment as adults. We quantified affiliative and agonistic interactions among the females during pregnancy and lactation of the focal female, maternal and allomaternal care, hypothalamic-anterior pituitary-adrenal axis (HPA) acute stress response, and early offspring growth. Social instability during breeding enhanced agonistic interactions among adult females, and offspring that experienced socially unstable conditions exhibited enhanced offspring care, regardless of adult environments. Neither social behavior, offspring care, acute stress physiology, nor early growth was influenced by early or adult social stability conditions. These findings imply that socially unstable conditions prime developing females to shape the phenotype of their offspring to prevent negative effects of socially unstable environments.
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Affiliation(s)
- Luis A Ebensperger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Celeste Gómez
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Antonia Aspillaga-Cid
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Cecilia León
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Ramírez-Estrada
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Loreto A Correa
- Escuela de Medicina Veterinaria, Facultad de Ciencias, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile
| | - Daniela C Vera
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sebastian Abades
- GEMA Center for Genomics, Ecology & Environment, Facultad de Estudios Interdisciplinarios, Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago, Chile
| | - Loren D Hayes
- Department of Biology, Geology, and Environmental Sciences, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA
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4
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Prolonged Social Isolation, Started Early in Life, Impairs Cognitive Abilities in Rats Depending on Sex. Brain Sci 2020; 10:brainsci10110799. [PMID: 33143056 PMCID: PMC7692092 DOI: 10.3390/brainsci10110799] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 11/23/2022] Open
Abstract
Background: The chronic stress of social isolation is a valid predictor of cognitive pathology. This study aimed to compare the effects of long-term social isolation on female versus male Wistar rats’ learning and memory. We hypothesized that prolonged social isolation stress, which starts early in life, would affect learning in a sex-dependent manner. Methods: Social isolation started at the edge of early to mid-adolescence and lasted 9 months. The rat’s cognitive abilities were assessed by habituation and reactivity to novelty in the open field (OF) test, spatial memory in the Morris water maze (MWM), and the conditioned passive avoidance (PA) reflex. Basal serum corticosterone levels were assessed using an enzyme-linked immunosorbent assay. Results: Regardless of the housing conditions, females habituated to the OF under low illumination slower than males. Under bright light, the single-housed rats showed hyporeactivity to novelty. In the MWM, all the rats learned to locate the platform; however, on the first training day, the single-housed females’ speed was lower relative to other groups. Four months later, in the post-reminder probe trial, the single-housed rats reached the area around the platform site later, and only males, regardless of housing conditions, preferred the target quadrant. Single-housed rats, irrespective of sex, showed a PA deficit. There was a more pronounced conditioned fear in the single-housed males than in females. In both male and female rats, basal corticosterone levels in rat blood serum after 9 months of social isolation did not differ from that in the group-housed rats of the corresponding sex. Meanwhile, females’ basal corticosterone level was higher than in males, regardless of the housing conditions. The relative weight of the adrenal glands was increased only in single-housed females. Conclusions: Under long-term social isolation, started early in life, single-housed females compared with males showed more pronounced cognitive impairments in the MWM and PA paradigm, findings that specify their greater vulnerability to the stress of prolonged social isolation.
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5
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Almeida J, Oliveira LA, Benini R, Crestani CC. Role of hippocampal nitrergic neurotransmission in behavioral and cardiovascular dysfunctions evoked by chronic social stress. Nitric Oxide 2020; 94:114-124. [DOI: 10.1016/j.niox.2019.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/18/2019] [Accepted: 11/18/2019] [Indexed: 12/21/2022]
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6
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Schipper L, Harvey L, van der Beek EM, van Dijk G. Home alone: a systematic review and meta-analysis on the effects of individual housing on body weight, food intake and visceral fat mass in rodents. Obes Rev 2018; 19:614-637. [PMID: 29334694 DOI: 10.1111/obr.12663] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/11/2017] [Accepted: 11/21/2017] [Indexed: 12/09/2022]
Abstract
Rats and mice are widely used to study environmental effects on psychological and metabolic health. Study designs differ widely and are often characterized by varying (social) housing conditions. In itself, housing has a profound influence on physiology and behaviour of rodents, affecting energy balance and sustainable metabolic health. However, evidence for potential long-term consequences of individual versus social housing on body weight and metabolic phenotype is inconsistent. We conducted a systematic literature review and meta-analyses assessing effects of individual versus social housing of rats and mice, living under well-accepted laboratory conditions, on measures of metabolic health, including body weight, food intake and visceral adipose tissue mass. Seventy-one studies were included in this review; 59 were included in the meta-analysis. Whilst housing did not affect body weight, both food intake and visceral adipose tissue mass were significantly higher in individually compared with socially housed animals. A combination of emotional stress and lack of social thermoregulation likely contributed to these effects. Increased awareness of consequences and improved specifications of housing conditions are necessary to accurately evaluate efficacy of drugs, diets or other interventions on metabolic and other health outcomes because housing conditions are rarely considered as possible moderators of reported outcomes.
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Affiliation(s)
- L Schipper
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Neurobiology Cluster, Department Behavioural Neurosciences, University of Groningen, Groningen, The Netherlands.,Nutricia Research, Utrecht, The Netherlands
| | | | - E M van der Beek
- Nutricia Research, Utrecht, The Netherlands.,Department of Paediatrics, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - G van Dijk
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Neurobiology Cluster, Department Behavioural Neurosciences, University of Groningen, Groningen, The Netherlands
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7
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Arakawa H. Ethological approach to social isolation effects in behavioral studies of laboratory rodents. Behav Brain Res 2018; 341:98-108. [DOI: 10.1016/j.bbr.2017.12.022] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/15/2017] [Accepted: 12/17/2017] [Indexed: 12/31/2022]
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8
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Cacioppo JT, Cacioppo S. Loneliness in the Modern Age: An Evolutionary Theory of Loneliness (ETL). ADVANCES IN EXPERIMENTAL SOCIAL PSYCHOLOGY 2018. [DOI: 10.1016/bs.aesp.2018.03.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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9
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Adolescent vulnerability to cardiovascular consequences of chronic emotional stress: Review and perspectives for future research. Neurosci Biobehav Rev 2017; 74:466-475. [DOI: 10.1016/j.neubiorev.2016.03.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/28/2016] [Accepted: 03/29/2016] [Indexed: 12/26/2022]
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10
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Crestani CC. Emotional Stress and Cardiovascular Complications in Animal Models: A Review of the Influence of Stress Type. Front Physiol 2016; 7:251. [PMID: 27445843 PMCID: PMC4919347 DOI: 10.3389/fphys.2016.00251] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/09/2016] [Indexed: 01/22/2023] Open
Abstract
Emotional stress has been recognized as a modifiable risk factor for cardiovascular diseases. The impact of stress on physiological and psychological processes is determined by characteristics of the stress stimulus. For example, distinct responses are induced by acute vs. chronic aversive stimuli. Additionally, the magnitude of stress responses has been reported to be inversely related to the degree of predictability of the aversive stimulus. Therefore, the purpose of the present review was to discuss experimental research in animal models describing the influence of stressor stimulus characteristics, such as chronicity and predictability, in cardiovascular dysfunctions induced by emotional stress. Regarding chronicity, the importance of cardiovascular and autonomic adjustments during acute stress sessions and cardiovascular consequences of frequent stress response activation during repeated exposure to aversive threats (i.e., chronic stress) is discussed. Evidence of the cardiovascular and autonomic changes induced by chronic stressors involving daily exposure to the same stressor (predictable) vs. different stressors (unpredictable) is reviewed and discussed in terms of the impact of predictability in cardiovascular dysfunctions induced by stress.
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Affiliation(s)
- Carlos C Crestani
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista Araraquara, Brasil
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11
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Hawkley LC, Capitanio JP. Perceived social isolation, evolutionary fitness and health outcomes: a lifespan approach. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0114. [PMID: 25870400 DOI: 10.1098/rstb.2014.0114] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Sociality permeates each of the fundamental motives of human existence and plays a critical role in evolutionary fitness across the lifespan. Evidence for this thesis draws from research linking deficits in social relationship--as indexed by perceived social isolation (i.e. loneliness)--with adverse health and fitness consequences at each developmental stage of life. Outcomes include depression, poor sleep quality, impaired executive function, accelerated cognitive decline, unfavourable cardiovascular function, impaired immunity, altered hypothalamic pituitary-adrenocortical activity, a pro-inflammatory gene expression profile and earlier mortality. Gaps in this research are summarized with suggestions for future research. In addition, we argue that a better understanding of naturally occurring variation in loneliness, and its physiological and psychological underpinnings, in non-human species may be a valuable direction to better understand the persistence of a 'lonely' phenotype in social species, and its consequences for health and fitness.
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Affiliation(s)
- Louise C Hawkley
- Academic Research Centers, National Opinion Research Center at the University of Chicago, Chicago, IL 60637, USA
| | - John P Capitanio
- California National Primate Research Center, University of California, Davis, CA 95616, USA
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12
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Cruz FC, Duarte JO, Leão RM, Hummel LFV, Planeta CS, Crestani CC. Adolescent vulnerability to cardiovascular consequences of chronic social stress: Immediate and long-term effects of social isolation during adolescence. Dev Neurobiol 2015; 76:34-46. [PMID: 25914339 DOI: 10.1002/dneu.22297] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/21/2015] [Accepted: 04/21/2015] [Indexed: 11/09/2022]
Abstract
It has been demonstrated that disruption of social bonds and perceived isolation (loneliness) are associated with an increased risk of cardiovascular morbidity and mortality. Adolescence is proposed as a period of vulnerability to stress. Nevertheless, the impact of chronic social stress during this ontogenic period in cardiovascular function is poorly understood. Therefore, the purpose of this study was to compare the impact in cardiovascular function of social isolation for 3 weeks in adolescent and adult male rats. Also, the long-term effects of social isolation during adolescence were investigated longitudinally. Social isolation reduced body weight in adolescent, but not in adult animals. Disruption of social bonds during adolescence increased arterial pressure without affecting heart rate and pulse pressure (PP). Nevertheless, social isolation in adulthood reduced systolic arterial pressure and increased diastolic arterial pressure, which in turn decreased PP without affecting mean arterial pressure. Cardiovascular changes in adolescents, but not adults, were followed by facilitation of both baroreflex sensitivity and vascular reactivity to the vasodilator agent acetylcholine. Vascular responsiveness to either the vasodilator agent sodium nitroprusside or the vasoconstrictor agent phenylephrine was not affected by social isolation. Except for the changes in body weight and baroreflex sensitivity, all alterations evoked by social isolation during adolescence were reversed in adulthood after moving animals from isolated to collective housing. These findings suggest a vulnerability of adolescents to the effects of chronic social isolation in cardiovascular function. However, results indicate minimal cardiovascular consequences in adulthood of disruption of social bonds during adolescence.
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Affiliation(s)
- Fábio C Cruz
- Laboratory of Pharmacology, Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP, Brazil.,Department of Health and Human Services, Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, US National Institutes of Health, Baltimore, Maryland
| | - Josiane O Duarte
- Laboratory of Pharmacology, Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP, Brazil.,Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil
| | - Rodrigo M Leão
- Laboratory of Pharmacology, Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP, Brazil.,Department of Health and Human Services, Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, US National Institutes of Health, Baltimore, Maryland
| | - Luiz F V Hummel
- Laboratory of Pharmacology, Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP, Brazil
| | - Cleopatra S Planeta
- Laboratory of Pharmacology, Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP, Brazil.,Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil
| | - Carlos C Crestani
- Laboratory of Pharmacology, Department of Natural Active Principles and Toxicology, School of Pharmaceutical Sciences, São Paulo State University, UNESP, Araraquara, SP, Brazil.,Joint UFSCar-UNESP Graduate Program in Physiological Sciences, São Carlos, SP, Brazil
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13
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Fournier S, Kinkead R, Joseph V. Influence of housing conditions from weaning to adulthood on the ventilatory, thermoregulatory, and endocrine responses to hypoxia of adult female rats. J Appl Physiol (1985) 2012; 112:1474-81. [PMID: 22323657 DOI: 10.1152/japplphysiol.01477.2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Housing conditions affect animal physiology. We previously showed that the hypoxic ventilatory and thermoregulatory responses to hypoxia of adult male rats housed in triads during the juvenile period (postnatal day 21 to adulthood) were significantly reduced compared with animals housed in pairs. Because sex hormones influence development and responsiveness to environmental stressors, this study investigated the impact of housing on the respiratory and thermoregulatory physiology of female rats. Since neonatal stress attenuates the hypoxic ventilatory response (HVR) of female rats at adulthood, experiments were performed both on "control" (undisturbed) animals and rats subjected to neonatal maternal separation (NMS; 3 h/day, postnatal days 3-12). At adulthood, ventilatory activity was measured by whole body plethysmography under normoxic and hypoxic conditions [fraction of inspired oxygen (Fi(O(2))) = 0.12; 20 min]. The ventilatory and body temperature responses to hypoxia of female rats raised in triads were reduced compared with rats housed in pairs. Housing female rats in triads did not affect basal or hypoxic plasma corticosterone levels but did increase levels of estradiol significantly. We conclude that modest changes in housing conditions (pairs vs. triads) from weaning to adulthood does influence basic homeostatic functions such as temperature and respiratory regulation. Triad housing can reverse the manifestations of respiratory instability at adulthood induced by stressful neonatal treatments. This should raise awareness of the benefits of increasing social interactions in clinical settings but also caution researchers of the potential impact of such subtle changes on experimental protocols and interpretation of results.
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Affiliation(s)
- Sébastien Fournier
- Department of Pediatrics, Centre de Recherche Hospitalier Universitaire de Québec, Université Laval, Québec, QC, Canada.
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14
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Eiland L, Ramroop J, Hill MN, Manley J, McEwen BS. Chronic juvenile stress produces corticolimbic dendritic architectural remodeling and modulates emotional behavior in male and female rats. Psychoneuroendocrinology 2012; 37:39-47. [PMID: 21658845 PMCID: PMC3181388 DOI: 10.1016/j.psyneuen.2011.04.015] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/22/2011] [Accepted: 04/26/2011] [Indexed: 01/06/2023]
Abstract
Nearly 12% of US children are exposed to intense adverse experiences. Research has demonstrated that these experiences can negatively impact adult health, often resulting in psychopathology. Less attention, however, is given to the impact of childhood adverse experiences on childhood health and wellbeing. Using a rodent model of chronic juvenile stress (restraint 6 h daily from postnatal day 20 to 41), we report that chronic stress has significant immediate morbidities in both males and females during this developmental window. Specifically, we demonstrate that chronic juvenile stress produces depressive-like behavior and significant neuronal remodeling of brain regions likely involved in these behavioral alterations: the hippocampus, prefrontal cortex and amygdala. Chronically stressed males and females exhibit anhedonia, increased locomotion when exposed to novelty, and altered coping strategies when exposed to acute stress. Coincident with these behavioral changes, we report simplification of dendrites in the hippocampus and prefrontal cortex and concurrent hypertrophy of dendrites in the amygdala. Taken together, these results demonstrate that chronically stressed juveniles exhibit aberrant behavioral responses to acute challenges that occur in conjunction with stress-induced remodeling of brain regions intimately involved in regulating emotionality and stress reactivity. Further, the absence of sex differences in our reported stress responses, likely speaks to the decreased sensitivity of immature HPA regulating brain regions to sex hormones.
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Affiliation(s)
- Lisa Eiland
- Weill Cornell Medical College, Department of Pediatrics, New York, NY, USA.
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15
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Fournier S, Joseph V, Kinkead R. Influence of juvenile housing conditions on the ventilatory, thermoregulatory, and endocrine responses to hypoxia of adult male rats. J Appl Physiol (1985) 2011; 111:516-23. [DOI: 10.1152/japplphysiol.00370.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
“Extreme” housing conditions, such as isolation (single housing) or crowding, are stressful for rats, and their deleterious impact on behavior is well documented. To determine whether more subtle variations in housing can affect animal physiology, the present study tested the hypothesis that the hypoxic ventilatory response (HVR) of adult male rats housed in pairs during the juvenile period (postnatal day 21 to adulthood) does not differ from that of animals housed in triads. Because neonatal stress augments the neuroendocrine responsiveness to stress and HVR, experiments were performed both on “control” (undisturbed) animals and rats subjected to neonatal maternal separation (NMS; 3 h/day, postnatal days 3–12). At adulthood, ventilatory activity was measured by whole body plethysmography under normoxic and hypoxic conditions (inspired fraction of O2 = 0.12; 20 min). The ventilatory and body temperature responses to hypoxia of rats raised in triads were less than those of rats housed in pairs. For the HVR, however, the attenuation induced by triad housing was more important in NMS rats. Triad housing decreased “basal” plasma corticosterone, but increased estradiol and testosterone levels. Much like the HVR, housing-related decrease in corticosterone level was greater in NMS than control rats. We conclude that modest changes in housing conditions (pairs vs. triads) during the juvenile period can influence basic homeostatic functions, such as temperature, endocrine, and respiratory regulation. Housing conditions can influence (even eliminate) the manifestations of respiratory plasticity subsequent to deleterious neonatal treatments. Differences in neuroendocrine function likely contribute to these effects.
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Affiliation(s)
- Sébastien Fournier
- Department of Pediatrics, Centre de Recherche Hospitalier Universitaire de Québec, Université Laval, Québec, Canada
| | - Vincent Joseph
- Department of Pediatrics, Centre de Recherche Hospitalier Universitaire de Québec, Université Laval, Québec, Canada
| | - Richard Kinkead
- Department of Pediatrics, Centre de Recherche Hospitalier Universitaire de Québec, Université Laval, Québec, Canada
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