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Cholecystokinin B receptor gene polymorphism (rs2941026) is associated with anxious personality and suicidal thoughts in a longitudinal study. Acta Neuropsychiatr 2022; 34:201-211. [PMID: 34924075 DOI: 10.1017/neu.2021.41] [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] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Cholecystokinin is a neuropeptide with a role in the neurobiology of adaptive behaviour that is implicated in anxiety disorders, while the underlying mechanisms currently remain insufficiently explained. The rs2941026 variation in the cholecystokinin B receptor gene has previously been associated with trait anxiety. Our aim was to investigate associations between the CCKB receptor gene polymorphism rs2941026 with anxiety, personality, depressiveness and suicidality in a longitudinal study of late adolescence and early adulthood. METHODS We used reports on trait and state anxiety, depressiveness and suicidal thoughts, as well as Affective Neuroscience Personality Scales, from the two birth cohorts of the Estonian Children Personality, Behaviour and Health Study. We measured associations between the CCKBR gene rs2941026 and anxiety-related phenotypes both longitudinally and cross-sectionally at ages 15, 18, 25 and 33. RESULTS Homozygosity for both alleles of the CCKBR rs2941026 was associated with higher trait and state anxiety in the longitudinal analysis. Cross-sectional comparisons were statistically significant at ages 18 and 25 for trait anxiety and at ages 25 and 33 for state anxiety. Higher depressiveness and suicidal thoughts were associated with the A/A genotype at age 18. Additionally, homozygosity for the A-allele was related to higher FEAR and SADNESS in the Affective Neuroscience Personality Scales. The genotype effects were more apparent in females, who displayed higher levels of negative affect overall. CONCLUSIONS CCKBR genotype is persistently associated with negative affect in adolescence and young adulthood. The association of the CCKBR rs2941026 genotype with anxiety-related phenotypes is more pronounced in females.
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Hou X, Rong C, Wang F, Liu X, Sun Y, Zhang HT. GABAergic System in Stress: Implications of GABAergic Neuron Subpopulations and the Gut-Vagus-Brain Pathway. Neural Plast 2020; 2020:8858415. [PMID: 32802040 PMCID: PMC7416252 DOI: 10.1155/2020/8858415] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 02/07/2023] Open
Abstract
Stress can cause a variety of central nervous system disorders, which are critically mediated by the γ-aminobutyric acid (GABA) system in various brain structures. GABAergic neurons have different subsets, some of which coexpress certain neuropeptides that can be found in the digestive system. Accumulating evidence demonstrates that the gut-brain axis, which is primarily regulated by the vagus nerve, is involved in stress, suggesting a communication between the "gut-vagus-brain" pathway and the GABAergic neuronal system. Here, we first summarize the evidence that the GABAergic system plays an essential role in stress responses. In addition, we review the effects of stress on different brain regions and GABAergic neuron subpopulations, including somatostatin, parvalbumin, ionotropic serotonin receptor 5-HT3a, cholecystokinin, neuropeptide Y, and vasoactive intestinal peptide, with regard to signaling events, behavioral changes, and pathobiology of neuropsychiatric diseases. Finally, we discuss the gut-brain bidirectional communications and the connection of the GABAergic system and the gut-vagus-brain pathway.
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Affiliation(s)
- Xueqin Hou
- Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai'an, Shandong 271016, China
| | - Cuiping Rong
- The Second Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Fugang Wang
- Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai'an, Shandong 271016, China
| | - Xiaoqian Liu
- Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai'an, Shandong 271016, China
| | - Yi Sun
- Institute of Pharmacology, Shandong First Medical University & Shandong Academy of Medical Sciences, Tai'an, Shandong 271016, China
| | - Han-Ting Zhang
- Departments of Neuroscience and Behavioral Medicine & Psychiatry, The Rockefeller Neurosciences Institute, West Virginia University Health Sciences Center, Morgantown, WV 26506, USA
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Weidner MT, Lardenoije R, Eijssen L, Mogavero F, De Groodt LPMT, Popp S, Palme R, Förstner KU, Strekalova T, Steinbusch HWM, Schmitt-Böhrer AG, Glennon JC, Waider J, van den Hove DLA, Lesch KP. Identification of Cholecystokinin by Genome-Wide Profiling as Potential Mediator of Serotonin-Dependent Behavioral Effects of Maternal Separation in the Amygdala. Front Neurosci 2019; 13:460. [PMID: 31133792 PMCID: PMC6524554 DOI: 10.3389/fnins.2019.00460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/24/2019] [Indexed: 01/05/2023] Open
Abstract
Converging evidence suggests a role of serotonin (5-hydroxytryptamine, 5-HT) and tryptophan hydroxylase 2 (TPH2), the rate-limiting enzyme of 5-HT synthesis in the brain, in modulating long-term, neurobiological effects of early-life adversity. Here, we aimed at further elucidating the molecular mechanisms underlying this interaction, and its consequences for socio-emotional behaviors, with a focus on anxiety and social interaction. In this study, adult, male Tph2 null mutant (Tph2 -/-) and heterozygous (Tph2 +/-) mice, and their wildtype littermates (Tph2 +/+) were exposed to neonatal, maternal separation (MS) and screened for behavioral changes, followed by genome-wide RNA expression and DNA methylation profiling. In Tph2 -/- mice, brain 5-HT deficiency profoundly affected socio-emotional behaviors, i.e., decreased avoidance of the aversive open arms in the elevated plus-maze (EPM) as well as decreased prosocial and increased rule breaking behavior in the resident-intruder test when compared to their wildtype littermates. Tph2 +/- mice showed an ambiguous profile with context-dependent, behavioral responses. In the EPM they showed similar avoidance of the open arm but decreased prosocial and increased rule breaking behavior in the resident-intruder test when compared to their wildtype littermates. Notably, MS effects on behavior were subtle and depended on the Tph2 genotype, in particular increasing the observed avoidance of EPM open arms in wildtype and Tph2 +/- mice when compared to their Tph2 -/- littermates. On the genomic level, the interaction of Tph2 genotype with MS differentially affected the expression of numerous genes, of which a subset showed an overlap with DNA methylation profiles at corresponding loci. Remarkably, changes in methylation nearby and expression of the gene encoding cholecystokinin, which were inversely correlated to each other, were associated with variations in anxiety-related phenotypes. In conclusion, next to various behavioral alterations, we identified gene expression and DNA methylation profiles to be associated with TPH2 inactivation and its interaction with MS, suggesting a gene-by-environment interaction-dependent, modulatory function of brain 5-HT availability.
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Affiliation(s)
- Magdalena T. Weidner
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, Department of Psychiatry, University of Würzburg, Würzburg, Germany
- Department of Psychiatry and Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Roy Lardenoije
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
- Department of Psychiatry and Psychotherapy, Universitätsmedizin Göttingen, Georg-August-Universität, Göttingen, Germany
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, United States
| | - Lars Eijssen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
- Departments of Bioinformatics, Psychiatry & Neuro Psychology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, Netherlands
| | - Floriana Mogavero
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | | | - Sandy Popp
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, Department of Psychiatry, University of Würzburg, Würzburg, Germany
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Konrad U. Förstner
- Core Unit Systems Medicine, Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
- ZB MED – Information Centre for Life Sciences, Cologne, Germany
- TH Köln, Faculty of Information Science and Communication Studies, Cologne, Germany
| | - Tatyana Strekalova
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, Department of Psychiatry, University of Würzburg, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I. M. Sechenov First Moscow State Medical University and Institute of General Pathology and Pathophysiology, Moscow, Russia
| | - Harry W. M. Steinbusch
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
| | - Angelika G. Schmitt-Böhrer
- Center of Mental Health, Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Würzburg, Würzburg, Germany
| | - Jeffrey C. Glennon
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Jonas Waider
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, Department of Psychiatry, University of Würzburg, Würzburg, Germany
| | - Daniel L. A. van den Hove
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, Department of Psychiatry, University of Würzburg, Würzburg, Germany
| | - Klaus-Peter Lesch
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, Netherlands
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, Department of Psychiatry, University of Würzburg, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I. M. Sechenov First Moscow State Medical University and Institute of General Pathology and Pathophysiology, Moscow, Russia
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Fuentes S, Daviu N, Gagliano H, Belda X, Armario A, Nadal R. Early life stress in rats sex-dependently affects remote endocrine rather than behavioral consequences of adult exposure to contextual fear conditioning. Horm Behav 2018; 103:7-18. [PMID: 29802874 DOI: 10.1016/j.yhbeh.2018.05.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 05/22/2018] [Indexed: 01/07/2023]
Abstract
Exposure to electric foot-shocks can induce in rodents contextual fear conditioning, generalization of fear to other contexts and sensitization of the hypothalamic-pituitary-adrenal (HPA) axis to further stressors. All these aspects are relevant for the study of post-traumatic stress disorder. In the present work we evaluated in rats the sex differences and the role of early life stress (ELS) in fear memories, generalization and sensitization. During the first postnatal days subjects were exposed to restriction of nesting material along with exposure to a "substitute" mother. In the adulthood they were exposed to (i) a contextual fear conditioning to evaluate long-term memory and extinction and (ii) to a novel environment to study cognitive fear generalization and HPA axis heterotypic sensitization. ELS did not alter acquisition, expression or extinction of context fear conditioned behavior (freezing) in either sex, but reduced activity in novel environments only in males. Fear conditioning associated hypoactivity in novel environments (cognitive generalization) was greater in males than females but was not specifically affected by ELS. Although overall females showed greater basal and stress-induced levels of ACTH and corticosterone, an interaction between ELS, shock exposure and sex was found regarding HPA hormones. In males, ELS did not affect ACTH response in any situation, whereas in females, ELS reduced both shock-induced sensitization of ACTH and its conditioned response to the shock context. Also, shock-induced sensitization of corticosterone was only observed in males and ELS specifically reduced corticosterone response to stressors in males but not females. In conclusion, ELS seems to have only a minor impact on shock-induced behavioral conditioning, while affecting the unconditioned and conditioned responses of HPA hormones in a sex-dependent manner.
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Affiliation(s)
- Sílvia Fuentes
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; Animal Physiology Unit, School of Biosciences, Universitat Autònoma de Barcelona, Spain
| | - Núria Daviu
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; Psychobiology Unit, School of Psychology, Universitat Autònoma de Barcelona, Spain
| | - Humberto Gagliano
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; Psychobiology Unit, School of Psychology, Universitat Autònoma de Barcelona, Spain
| | - Xavier Belda
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; Psychobiology Unit, School of Psychology, Universitat Autònoma de Barcelona, Spain
| | - Antonio Armario
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; Psychobiology Unit, School of Psychology, Universitat Autònoma de Barcelona, Spain; CIBERSAM, Instituto de Salud Carlos III, Spain.
| | - Roser Nadal
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; Animal Physiology Unit, School of Biosciences, Universitat Autònoma de Barcelona, Spain; CIBERSAM, Instituto de Salud Carlos III, Spain.
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Sadeghi M, Reisi P, Radahmadi M. The effects of CCK-8S on spatial memory and long-term potentiation at CA1 during induction of stress in rats. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2017; 20:1368-1376. [PMID: 29238473 PMCID: PMC5722998 DOI: 10.22038/ijbms.2017.9619] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Objectives Cholecystokinin (CCK) has been proposed as a mediator in stress. However, it is still not fully documented what are its effects. We aimed to evaluate the effects of systemic administration of CCK exactly before induction of stress on spatial memory and synaptic plasticity at CA1 in rats. Materials and Methods Male Wistar rats were divided into 4 groups: the control, the control-CCK, the stress and the stress-CCK. Restraint stress was induced 6 hr per day, for 24 days. Cholecystokinin sulfated octapeptide (CCK-8S) was injected (1.6 µg/kg, IP) before each session of stress induction. Spatial memory was evaluated by Morris water maze test. Long-term potentiation (LTP) in Schaffer collateral-CA1 synapses was assessed (by 100 Hz tetanization) in order to investigate synaptic plasticity. Results Stress impaired spatial memory significantly (P<0.01). CCK in the control rats improved memory (P<0.05), and prevented the impairments in the stress group. With respect to the control group, both fEPSP amplitude and slope were significantly (P<0.05) decreased in the stress group. However, there were no differences between responses of the control-CCK and Stress-CCK groups compared to the control group. Conclusion The present results suggest that high levels of CCK-8S during induction of stress can modulate the destructive effects of stress on hippocampal synaptic plasticity and memory. Therefore, the mediatory effects of CCK in stress are likely as compensatory responses.
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Affiliation(s)
- Malihe Sadeghi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Parham Reisi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam Radahmadi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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Early Life Stress, Nicotinic Acetylcholine Receptors and Alcohol Use Disorders. Brain Sci 2015; 5:258-74. [PMID: 26136145 PMCID: PMC4588139 DOI: 10.3390/brainsci5030258] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/11/2015] [Accepted: 06/18/2015] [Indexed: 01/01/2023] Open
Abstract
Stress is a major driving force in alcohol use disorders (AUDs). It influences how much one consumes, craving intensity and whether an abstinent individual will return to harmful alcohol consumption. We are most vulnerable to the effects of stress during early development, and exposure to multiple traumatic early life events dramatically increases the risk for AUDs. However, not everyone exposed to early life stress will develop an AUD. The mechanisms determining whether an individual’s brain adapts and becomes resilient to the effects of stress or succumbs and is unable to cope with stress remain elusive. Emerging evidence suggests that neuroplastic changes in the nucleus accumbens (NAc) following early life stress underlie the development of AUDs. This review discusses the impact of early life stress on NAc structure and function, how these changes affect cholinergic signaling within the mesolimbic reward pathway and the role nicotinic acetylcholine receptors (nAChRs) play in this process. Understanding the neural pathways and mechanism determining stress resilience or susceptibility will improve our ability to identify individuals susceptible to developing AUDs, formulate cognitive interventions to prevent AUDs in susceptible individuals and to elucidate and enhance potential therapeutic targets, such as the nAChRs, for those struggling to overcome an AUD.
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Bali A, Jaggi AS. Preclinical experimental stress studies: protocols, assessment and comparison. Eur J Pharmacol 2014; 746:282-92. [PMID: 25446911 DOI: 10.1016/j.ejphar.2014.10.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/08/2014] [Accepted: 10/09/2014] [Indexed: 01/05/2023]
Abstract
Stress is a state of threatened homeostasis during which a variety of adaptive processes are activated to produce physiological and behavioral changes. Preclinical models are pivotal for understanding these physiological or pathophysiological changes in the body in response to stress. Furthermore, these models are also important for the development of novel pharmacological agents for stress management. The well described preclinical stress models include immobilization, restraint, electric foot shock and social isolation stress. Stress assessment in animals is done at the behavioral level using open field, social interaction, hole board test; at the biochemical level by measuring plasma corticosterone and ACTH; at the physiological level by measuring food intake, body weight, adrenal gland weight and gastric ulceration. Furthermore the comparison between different stressors including electric foot shock, immobilization and cold stressor is described in terms of intensity, hormonal release, protein changes in brain, adaptation and sleep pattern. This present review describes these preclinical stress protocols, and stress assessment at different levels.
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Affiliation(s)
- Anjana Bali
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, India.
| | - Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, India.
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Affiliation(s)
- Mary F Dallman
- Department of Physiology, University of California, San Francisco, California 94143
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Fuentes S, Daviu N, Gagliano H, Garrido P, Zelena D, Monasterio N, Armario A, Nadal R. Sex-dependent effects of an early life treatment in rats that increases maternal care: vulnerability or resilience? Front Behav Neurosci 2014; 8:56. [PMID: 24616673 PMCID: PMC3934416 DOI: 10.3389/fnbeh.2014.00056] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 02/05/2014] [Indexed: 11/13/2022] Open
Abstract
Early life stress (ELS) in rodents has profound long-term effects that are partially mediated by changes in maternal care. ELS not only induces “detrimental” effects in adulthood, increasing psychopathology, but also promotes resilience to further stressors. In Long-Evans rats, we evaluated a combination of two procedures as a model of ELS: restriction of bedding during the first post-natal days and exposure to a “substitute” mother. The maternal care of biological and “substitute” mothers was measured. The male and female offspring were evaluated during adulthood in several contexts. Anxiety was measured by the elevated plus-maze (EPM), acoustic startle response (ASR) and forced swim test (FST). In other group of animals, novelty-seeking was measured (activity in an inescapable novel environment, preference for novel environments and exploration of novel objects). Plasmatic ACTH and corticosterone in basal conditions and in response to stress were also measured. Cognitive impulsivity was assessed by a delay-discounting paradigm, and impulsive action, attention and compulsive-like behavior by a five choice serial reaction time task (5CSRTT). ELS decreased pup body weight and increased the care of the biological mother; however, the “substitute” mother did not exhibit overt maltreatment. A mixture of “detrimental” and “beneficial” effects was shown. In the 5CSRTT, attention was impaired in both genders, and in females, ELS increased compulsive-like behavior. Novel object exploration was only increased by ELS in males, but the preference for novel spaces decreased in both genders. Baseline anxiety (EPM and ASR) and recognition memory were not affected. Unexpectedly, ELS decreased the ACTH response to novelty and swim stress and increased active coping in the FST in both genders. Cognitive impulsivity was decreased only in females, but impulsive action was not affected. The enhancement in maternal care may “buffer” the effects of ELS in a context-dependent manner.
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Affiliation(s)
- Sílvia Fuentes
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Núria Daviu
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain ; Animal Physiology Unit, School of Biosciences, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Humberto Gagliano
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain ; Animal Physiology Unit, School of Biosciences, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Pedro Garrido
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Dóra Zelena
- Institute of Experimental Medicine, Hungarian Academy of Science Budapest, Hungary
| | - Nela Monasterio
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain ; Psychobiology Unit, School of Psychology, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Antonio Armario
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain ; Animal Physiology Unit, School of Biosciences, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Roser Nadal
- Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain ; Psychobiology Unit, School of Psychology, Universitat Autònoma de Barcelona Barcelona, Spain
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Nylander I, Roman E. Is the rodent maternal separation model a valid and effective model for studies on the early-life impact on ethanol consumption? Psychopharmacology (Berl) 2013; 229:555-69. [PMID: 23982922 PMCID: PMC3782650 DOI: 10.1007/s00213-013-3217-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 07/10/2013] [Indexed: 12/18/2022]
Abstract
RATIONALE Early-life events can cause long-term neurobiological and behavioural changes with a resultant effect upon reward and addiction processes that enhance risk to develop alcohol use disorders. Maternal separation (MS) is used to study the mediating mechanisms of early-life influences in rodents. In MS studies, the pups are exposed to maternal absence during the first postnatal weeks. The outcome of MS experiments exhibits considerable variation and questions have been raised about the validity of MS models. OBJECTIVES This short review aims to provide information about experimental conditions that are important to consider when assessing the impact of early-life environment on voluntary ethanol consumption. RESULTS The results from currently used MS protocols are not uniform. However, studies consistently show that longer separations of intact litters predispose for higher ethanol consumption and/or preference in adult male rats as compared to shorter periods of MS. Studies using individual pup MS paradigms, other controls, low ethanol concentrations, adult females or examining adolescent consumption reported no differences or inconsistent results. CONCLUSIONS There is no "a rodent MS model", there are several models and they generate different results. The compiled literature shows that MS is a model of choice for analysis of early-life effects on voluntary ethanol consumption but there are examples of MS paradigms that are not suitable. These studies emphasize the importance to carefully designed MS experiments to supply the optimal conditions to definitely test the research hypothesis and to be particulate in the interpretation of the outcome.
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Affiliation(s)
- Ingrid Nylander
- Department of Pharmaceutical Biosciences, Neuropharmacology Addiction & Behaviour, Uppsala University, Box 591, 751 24, Uppsala, Sweden,
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Díaz-Morán S, Palència M, Mont-Cardona C, Cañete T, Blázquez G, Martínez-Membrives E, López-Aumatell R, Sabariego M, Donaire R, Morón I, Torres C, Martínez-Conejero JA, Tobeña A, Esteban FJ, Fernández-Teruel A. Gene expression in amygdala as a function of differential trait anxiety levels in genetically heterogeneous NIH-HS rats. Behav Brain Res 2013; 252:422-31. [PMID: 23777796 DOI: 10.1016/j.bbr.2013.05.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/07/2013] [Accepted: 05/10/2013] [Indexed: 12/12/2022]
Abstract
To identify genes involved in anxiety/fear traits, we analyzed the gene expression profile in the amygdala of genetically heterogeneous NIH-HS rats. The NIH-HS rat stock has revealed to be a unique genetic resource for the fine mapping of Quantitative Trait Loci (QTLs) to very small genomic regions, due to the high amount of genetic recombinants accumulated along more than 50 breeding generations, and for the same reason it can be expected that those genetically heterogeneous rats should be especially useful for studying differential gene expression as a function of anxiety-(or other)-related traits. We selected high- and low-anxious NIH-HS rats differing in their number of avoidances in a single 50-trial session of the two-way active avoidance task. Rats were also tested in unconditioned anxiety tests (e.g., elevated zero-maze). Three weeks after behavioural testing, the amygdala was dissected and prepared for the microarray study. There appeared 6 significantly down-regulated and 28 up-regulated genes (fold-change >|2|, FDR<0.05) between the low- and high-anxious groups, with central nervous system-related functions. Regression analyses (stepwise) revealed that differential expression of some genes could be predictive of anxiety/fear responses. Among those genes for which the present results suggest a link with individual differences in trait anxiety, six relevant genes were examined with qRT-PCR, four of which (Ucn3, Tacr3, H2-M9 and Arr3) were validated. Remarkably, some of them are characterized by sharing known functions related with hormonal HPA-axis responses to (and/or modulation of) stress, anxiety or fear, and putative involvement in related neurobehavioural functions. The results confirm the usefulness of NIH-HS rats as a good animal model for research on the neurogenetic basis of anxiety and fear, while suggesting the involvement of some neuropeptide/neuroendocrine pathways on the development of differential anxiety profiles.
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Affiliation(s)
- Sira Díaz-Morán
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, School of Medicine, Universidad Autónoma de Barcelona, Barcelona, Spain.
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Psychological stress alters microstructure of the mandibular condyle in rats. Physiol Behav 2013; 110-111:129-39. [PMID: 23313405 DOI: 10.1016/j.physbeh.2013.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 01/02/2013] [Accepted: 01/06/2013] [Indexed: 11/21/2022]
Abstract
Psychological stress plays an important role in the occurrence and development of temporomandibular joint disorder (TMD). The correlation between psychological factors and TMD has been clinically shown, but the influence of psychological stress on the temporomandibular joint (TMJ) structure still lacks direct evidence. Here, we used communication box to establish the rat model of psychological stress. The stress level of animals was estimated by the elevated plus maze (EPM) test and hormonal assays. The histomorphology and three-dimensional microstructure of the rat condyles were observed by hematoxylin-eosin (HE) staining and Micro-CT, respectively. Compared with control rats, the anxious state of the stressed rats was evidenced by higher plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT), as well as lower ratios of open arm entries and time and lower time spent in open arms after 1, 2, 3, 4 and 5 week(s) post-exposure to psychological stimuli. HE staining and histomorphometric data analysis showed decreased thicknesses of the central and posterior condylar cartilages in stressed rats at weeks 3, 4 and 5, with the most obvious changes in the posterior part characterized by debonding and thinned fibrous layer, thickened proliferative layer, thinned mature layer and hypertrophic layer. Moreover, Micro-CT scanning revealed local lesion of the subchondral bone in the posterior condylar cartilages of stressed rats at week 5. Our findings indicate that pathologic changes of the histomorphology and three-dimensional microstructure occur in the condyles of stressed rats, hinting us a potential link between psychological factors and the pathogenesis or progression of TMD.
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Bardo MT, Neisewander JL, Kelly TH. Individual differences and social influences on the neurobehavioral pharmacology of abused drugs. Pharmacol Rev 2013; 65:255-90. [PMID: 23343975 PMCID: PMC3565917 DOI: 10.1124/pr.111.005124] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The interaction of drugs with biologic targets is a critical area of research, particularly for the development of medications to treat substance use disorders. In addition to understanding these drug-target interactions, however, there is a need to understand more fully the psychosocial influences that moderate these interactions. The first section of this review introduces some examples from human behavioral pharmacology that illustrate the clinical importance of this research. The second section covers preclinical evidence to characterize some of the key individual differences that alter drug sensitivity and abuse vulnerability, related primarily to differences in response to novelty and impulsivity. Evidence is presented to indicate that critical neuropharmacological mechanisms associated with these individual differences involve integrated neurocircuits underlying stress, reward, and behavioral inhibitory processes. The third section covers social influences on drug abuse vulnerability, including effects experienced during infancy, adolescence, and young adulthood, such as maternal separation, housing conditions, and social interactions (defeat, play, and social rank). Some of the same neurocircuits involved in individual differences also are altered by social influences, although the precise neurochemical and cellular mechanisms involved remain to be elucidated fully. Finally, some speculation is offered about the implications of this research for the prevention and treatment of substance abuse.
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Affiliation(s)
- M T Bardo
- Department of Psychology, University of Kentucky, BBSRB Room 447, 741 S. Limestone, Lexington, KY 40536-0509, USA.
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Nylander I, Roman E. Neuropeptides as mediators of the early-life impact on the brain; implications for alcohol use disorders. Front Mol Neurosci 2012; 5:77. [PMID: 22783165 PMCID: PMC3389713 DOI: 10.3389/fnmol.2012.00077] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 06/14/2012] [Indexed: 12/22/2022] Open
Abstract
The brain is constantly exposed to external and internal input and to function in an ever-changing environment we are dependent on processes that enable the brain to adapt to new stimuli. Exposure to postnatal environmental stimuli can interfere with vital adaption processes and cause long-term changes in physiological function and behavior. Early-life alterations in brain function may result in impaired ability to adapt to new situations, in altered sensitivity to challenges later in life and thereby mediate risk or protection for psychopathology such as alcohol use disorders (AUD). In clinical research the studies of mechanisms, mediators, and causal relation between early environmental factors and vulnerability to AUD are restricted and attempts are made to find valid animal models for studies of the early-life influence on the brain. This review focuses on rodent models and the effects of adverse and naturalistic conditions on peptide networks within the brain and pituitary gland. Importantly, the consequences of alcohol addiction are not discussed but rather neurobiological alterations that can cause risk consumption and vulnerability to addiction. The article reviews earlier results and includes new data and multivariate data analysis with emphasis on endogenous opioid peptides but also oxytocin and vasopressin. These peptides are vital for developmental processes and it is hypothesized that early-life changes in peptide networks may interfere with neuronal processes and thereby contribute the individual vulnerability for AUD. The summarized results indicate a link between early-life rearing conditions, opioids, and ethanol consumption and that the ethanol-induced effects and the treatment with opioid antagonists later in life are dependent on early-life experiences. Endogenous opioids are therefore of interest to further study in the early-life impact on individual differences in vulnerability to AUD and treatment outcome.
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Affiliation(s)
- Ingrid Nylander
- Department of Pharmaceutical Biosciences, Neuropharmacology Addiction and Behaviour, Uppsala UniversityUppsala, Sweden
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Tjong Y, Ip S, Lao L, Fong HHS, Sung JJY, Berman B, Che C. Analgesic effect of Coptis chinensis rhizomes (Coptidis Rhizoma) extract on rat model of irritable bowel syndrome. JOURNAL OF ETHNOPHARMACOLOGY 2011; 135:754-61. [PMID: 21511022 PMCID: PMC3100428 DOI: 10.1016/j.jep.2011.04.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/23/2011] [Accepted: 04/05/2011] [Indexed: 05/24/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Coptis chinensis rhizomes (Coptidis Rhizoma, CR), also known as "Huang Lian", is a common component of traditional Chinese herbal formulae used for the relief of abdominal pain and diarrhea. Yet, the action mechanism of CR extract in the treatment of irritable bowel syndrome is unknown. Thus, the aim of our present study is to investigate the effect of CR extract on neonatal maternal separation (NMS)-induced visceral hyperalgesia in rats and its underlying action mechanisms. MATERIALS AND METHODS Male Sprague-Dawley rats were subjected to 3-h daily maternal separation from postnatal day 2 to day 21 to form the NMS group. The control group consists of unseparated normal (N) rats. From day 60, rats were administrated CR (0.3, 0.8 and 1.3 g/kg) or vehicle (Veh; 0.5% carboxymethylcellulose solution) orally for 7 days for the test and control groups, respectively. RESULTS Electromyogram (EMG) signals in response to colonic distension were measured with the NMS rats showing lower pain threshold and increased EMG activity than those of the unseparated (N) rats. CR dose-dependently increased pain threshold response and attenuated EMG activity in the NMS rats. An enzymatic immunoassay study showed that CR treatment significantly reduced the serotonin (5HT) concentration from the distal colon of NMS rats compared to the Veh (control) group. Real-time quantitative PCR and Western-blotting studies showed that CR treatment substantially reduced NMS induced cholecystokinin (CCK) expression compared with the Veh group. CONCLUSIONS These results suggest that CR extract robustly reduces visceral pain that may be mediated via the mechanism of decreasing 5HT release and CCK expression in the distal colon of rats.
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Affiliation(s)
- Yungwui Tjong
- School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
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Bi-directional effect of cholecystokinin receptor-2 overexpression on stress-triggered fear memory and anxiety in the mouse. PLoS One 2010; 5:e15999. [PMID: 21209861 PMCID: PMC3012733 DOI: 10.1371/journal.pone.0015999] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 12/02/2010] [Indexed: 12/02/2022] Open
Abstract
Fear, an emotional response of animals to environmental stress/threats, plays an important role in initiating and driving adaptive response, by which the homeostasis in the body is maintained. Overwhelming/uncontrollable fear, however, represents a core symptom of anxiety disorders, and may disturb the homeostasis. Because to recall or imagine certain cue(s) of stress/threats is a compulsory inducer for the expression of anxiety, it is generally believed that the pathogenesis of anxiety is associated with higher attention (acquisition) selectively to stress or mal-enhanced fear memory, despite that the actual relationship between fear memory and anxiety is not yet really established. In this study, inducible forebrain-specific cholecystokinin receptor-2 transgenic (IF-CCKR-2 tg) mice, different stress paradigms, batteries of behavioral tests, and biochemical assays were used to evaluate how different CCKergic activities drive fear behavior and hormonal reaction in response to stresses with different intensities. We found that in IF-CCKR-2 tg mice, contextual fear was impaired following 1 trial of footshock, while overall fear behavior was enhanced following 36 trials of footshock, compared to their littermate controls. In contrast to a standard Yerkes-Dodson (inverted-U shaped) stress-fear relationship in control mice, a linearized stress-fear curve was observed in CCKR-2 tg mice following gradient stresses. Moreover, compared to 1 trial, 36 trials of footshock in these transgenic mice enhanced anxiety-like behavior in other behavioral tests, impaired spatial and recognition memories, and prolonged the activation of adrenocorticotropic hormone (ACTH) and glucocorticoids (CORT) following new acute stress. Taken together, these results indicate that stress may trigger two distinctive neurobehavioral systems, depending on both of the intensity of stress and the CCKergic tone in the brain. A “threshold theory” for this two-behavior system has been suggested.
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Daoura L, Haaker J, Nylander I. Early environmental factors differentially affect voluntary ethanol consumption in adolescent and adult male rats. Alcohol Clin Exp Res 2010; 35:506-15. [PMID: 21143247 DOI: 10.1111/j.1530-0277.2010.01367.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Previous studies using the maternal separation (MS) model have shown that environmental factors early in life affect adult ethanol consumption. Prolonged MS is related to enhanced propensity for high adult ethanol intake when compared to short MS. Less is known about the environmental impact on adolescent ethanol intake. In this study, the aim was to compare establishment of voluntary ethanol consumption in adolescent and adult rats subjected to different rearing conditions. METHODS Wistar rat pups were separated from their mother 0 minutes (MS0), 15 minutes (MS15), or 360 minutes (MS360) daily during postnatal days (PNDs) 1 to 20. After weaning, the male rats were divided into two groups; rats were given free access to water, 5 and 20% ethanol at either PND 26 or 68. Ethanol was provided in 24-hour sessions three times per week for 5 weeks. RESULTS MS resulted in altered ethanol consumption patterns around the pubertal period but otherwise the rearing conditions had little impact on ethanol consumption in adolescents. In adults, the establishment of ethanol consumption was dependent on the rearing condition. The adult MS0 and MS15 rats had a stable ethanol intake, whereas the MS360 rats increased both their ethanol intake and preference over time. CONCLUSIONS With the use of intermittent access to ethanol, new data were provided, which confirm the notion that MS360 represents a risk environment related to higher ethanol intake compared to MS15. The adolescent rats had higher ethanol intake than adult rats but the consumption was independent of rearing condition. Experiences during the first three postnatal weeks thus affect the establishment of voluntary ethanol consumption differently in adolescent and adult rats. Further studies are now warranted to examine the consequences of a combination of early environmental influence and high adolescent ethanol intake.
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Affiliation(s)
- Loudin Daoura
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, Sweden.
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Long-term consequences of early maternal deprivation in serotonergic activity and HPA function in adult rat. Neurosci Lett 2010; 480:7-11. [PMID: 20435091 DOI: 10.1016/j.neulet.2010.04.054] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 04/03/2010] [Accepted: 04/22/2010] [Indexed: 02/07/2023]
Abstract
Increasing body of evidence indicates that early life stressful events may induce permanent alterations in neurodevelopment, which in turn, could lead to the development of psychopathologies in adulthood. In particular, maternal deprivation (MD) for 24h in rats has been associated with several abnormalities in brain and behaviour during adulthood, relevant to the neurobiological substrate of anxiety disorders. The aim of the present study was to clarify the long-term effects of MD, on hypothalamo-pituitary-adrenal (HPA) axis activity and serotonergic (5-HT) function, in adulthood, subjects that have not been yet thoroughly investigated. For this purpose, Wistar rat pups were deprived from their mothers for a 24-h single period at postnatal day 9 (pnd 9) and were examined when aged 69-90 days. Plasma corticosterone and ACTH levels along with the animal's behaviour in an open field were used as indices of stress. Moreover, serotonergic activity was estimated in hypothalamus and hippocampus, key structures in the coordination of neuroendocrine and behavioural responses to stress. Interestingly, in adulthood, MD rats compared to controls, displayed decreased body weight, increased serotonergic activity and "anxiety" related behaviour, as well as elevated plasma corticosterone and ACTH levels. The findings of this study showed that MD results in long-term modifications in HPA axis and serotonergic activity indicating a clear relationship between early life stressful events and the development of anxiety-like disorders later in adulthood.
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Abstract
This paper examines the neurobiological explanatory trend in psychology, including the related and tacit roles of ontological materialism and reductionism. In addition, the role of Cartesian dualism in both psychology and cognitive neuroscience is explored. In both, the complex relationships between mind/brain and mind/body tend to be conceptualized through the framework of either ontic dualism or attribute dualism, both of which ultimately constrain notions of embodiment. Alternatively, this paper understands the body as the inseparable unity of being-in-the-world from which the Cartesian dichotomy of “mind” and “body” is abstracted. This alternative surpasses the constraints of dualism and reframes embodiment as intentionality incarnate and ultimately as “flesh.” The body, understood phenomenologically, emerges not as a “what” but as a “ what—how”—the manifestation in extension of our intentionality, the flesh of our projects in and of the world. We argue that this understanding is indispensable to a properly psychological perspective on embodiment.
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Gustafsson L, Oreland S, Hoffmann P, Nylander I. The impact of postnatal environment on opioid peptides in young and adult male Wistar rats. Neuropeptides 2008; 42:177-91. [PMID: 18082882 DOI: 10.1016/j.npep.2007.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 09/21/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
Abstract
Early environmental influences can change the neuronal development and thereby affect behavior in adult life. The aim in the present study was to thoroughly examine the impact of early environmental factors on endogenous opioids by using a rodent maternal separation (MS) model. The endogenous opioid peptide system is not fully developed at birth, and short- and/or long-term alterations may occur in these neural networks in animals exposed to manipulation of the postnatal environment. Rat pups were subjected to one of five rearing conditions; 15 min (MS15) litter (l) or individual (i), 360 min (MS360) l or i daily MS, or housed under normal animal facility rearing (AFR) conditions during postnatal days 1-21. Measurements of immunoreactive (ir) Met-enkephalin-Arg6Phe7 (MEAP) and dynorphin B (DYNB) peptide levels in the pituitary gland and in a number of brain areas, were performed at three and 10 weeks of age, respectively. MS-induced changes were more pronounced in ir MEAP levels, especially in individually separated rats at three weeks of age and in litter-separated rats at 10 weeks of age. The enkephalin and dynorphin systems have different developmental patterns, dynorphin appearing earlier, which may point at a more sensitive enkephalin system during the early postnatal weeks. The results provide evidence that opioid peptides are sensitive for early environmental factors and show that the separation conditions are critical and also result in changes manifesting at different time points. MS-induced effects were observed in areas related to stress, drug reward and dependence mechanisms. By describing effects on opioid peptides, the study addresses the possible role of a deranged endogenous opioid system in the previously described behavioral consequences of MS.
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Affiliation(s)
- Lisa Gustafsson
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, P.O. Box 591, SE-751 24 Uppsala, Sweden
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Gustafsson L, Zhou Q, Nylander I. Ethanol-induced effects on opioid peptides in adult male Wistar rats are dependent on early environmental factors. Neuroscience 2007; 146:1137-49. [PMID: 17391858 DOI: 10.1016/j.neuroscience.2007.02.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 02/05/2007] [Accepted: 02/20/2007] [Indexed: 11/21/2022]
Abstract
The vulnerability to develop alcoholism is dependent on both genetic and environmental factors. The neurobiological mechanisms underlying these factors are not fully understood but individual divergence in the endogenous opioid peptide system may contribute. We have previously reported that early-life experiences can affect endogenous opioids and also adult voluntary ethanol intake. In the present study, this line of research was continued and the effects of long-term voluntary ethanol drinking on the opioid system are described in animals reared in different environmental settings. Rat pups were subjected to 15 min (MS15) or 360 min (MS360) of daily maternal separation during postnatal days 1-21. At 10 weeks of age, male rats were exposed to voluntary ethanol drinking in a four-bottle paradigm with 5%, 10% and 20% ethanol solution in addition to water for 2 months. Age-matched controls received water during the same period. Immunoreactive (ir) Met-enkephalin-Arg6Phe7 (MEAP) and dynorphin B (DYNB) peptide levels were thereafter measured in the pituitary gland and several brain areas. In water-drinking animals, lower ir MEAP levels were observed in the MS360 rats in the hypothalamus, medial prefrontal cortex, striatum and the periaqueductal gray, whereas no differences were seen in ir DYNB levels. Long-term ethanol drinking induced lower ir MEAP levels in MS15 rats in the medial prefrontal cortex and the periaqueductal gray, whereas higher levels were detected in MS360 rats in the hypothalamus, striatum and the substantia nigra. Chronic voluntary drinking affected ir DYNB levels in the pituitary gland, hypothalamus and the substantia nigra, with minor differences between MS15 and MS360. In conclusion, manipulation of the early environment caused changes in the opioid system and a subsequent altered response to ethanol. The altered sensitivity of the opioid peptides to ethanol may contribute to the previously reported differences in ethanol intake between MS15 and MS360 rats.
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Affiliation(s)
- L Gustafsson
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, P.O. Box 591, SE-751 24 Uppsala, Sweden
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Roman E, Gustafsson L, Berg M, Nylander I. Behavioral profiles and stress-induced corticosteroid secretion in male Wistar rats subjected to short and prolonged periods of maternal separation. Horm Behav 2006; 50:736-47. [PMID: 16876800 DOI: 10.1016/j.yhbeh.2006.06.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 06/14/2006] [Accepted: 06/16/2006] [Indexed: 11/30/2022]
Abstract
Early life experiences are important for the development of neurobiobehavioral mechanisms and subsequent establishment of mental functions. In experimental animals, early life experiences can be studied using the maternal separation model. Maternal separation has been described to induce neurobiological changes and thus affect brain function, mental state and behavior. We have established a protocol in order to study the effects of repeated short and prolonged periods of maternal separation during the postnatal period on adult neurochemistry, voluntary ethanol intake and behavior. In the present experiment, we focus on the long-term effects of maternal separation on exploration and risk assessment behavior as well corticosteroid secretion. Rat pups were assigned to 15 min (MS15) or 360 min (MS360) of daily maternal separation and normal animal facility rearing (AFR) during postnatal days 1-21. To establish the adult behavioral profile in male rats, three tests were used: the Concentric Square Field (CSF), the Open Field (OF) and the Elevated Plus-maze (EPM). No differences between the three experimental groups were found in the traditional OF and EPM tests. The CSF test indicated that the MS360 rats were more explorative and expressed an altered risk assessment and risk-taking profile. In response to a restraint stress, MS360 rats had a blunted corticosterone release in contrast to MS15 and AFR rats. In contrast to previous results, the outcome of the present investigation does not support the notion that a prolonged period of maternal separation results in an adult phenotype characterized by an increased emotional reactivity.
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Affiliation(s)
- Erika Roman
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, P.O. Box 591, SE-751 24 Uppsala, Sweden.
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Rees SL, Steiner M, Fleming AS. Early deprivation, but not maternal separation, attenuates rise in corticosterone levels after exposure to a novel environment in both juvenile and adult female rats. Behav Brain Res 2006; 175:383-91. [PMID: 17081629 DOI: 10.1016/j.bbr.2006.09.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 09/08/2006] [Accepted: 09/19/2006] [Indexed: 11/16/2022]
Abstract
Separation from the maternal nest alters the hypothalamic-pituitary-adrenal (HPA) axis stress response in adult male rats, but little research has addressed how separation affects female rats. The following experiments investigated how early maternal separation from postnatal day (PND) 2 to 14 affected stress-induced corticosterone and ACTH after exposure to an open field in juvenile and adult female rats. Female rats were separated for 5 h daily from mother and littermates (early deprivation: ED), separated from mother but not littermates (maternal separation: MS), or animal facility reared (AFR). Male siblings were left with the mother rat during separation. Female rats were exposed to an open field arena either during the juvenile period (PND 30) or during adulthood (PND 80-100). Results show that ED juvenile female rats showed a lower corticosterone stress response than MS and AFR female rats when measured at 5 min post-stress, but no difference at 20 or 60 min post-stress. In adulthood, ED female rats showed comparable elevations of corticosterone as MS and AFR rats at 5 min post-stress but lower elevations at 20 min. In terms of behavior, there were no significant effects of early experience. However, in adulthood, ED and MS rats tended to show a decreased proportion of inner grid crossings of the open field compared to AFR rats, suggesting a tendency for increased anxiety in these two separation groups.
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Affiliation(s)
- Stephanie L Rees
- Department of Psychology, University of Toronto at Mississauga, 3359 Mississauga Road North, Mississauga, Ont. L5L 1C6, Canada
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