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Griflyuk AV, Postnikova TY, Malkin SL, Zaitsev AV. Alterations in Rat Hippocampal Glutamatergic System Properties after Prolonged Febrile Seizures. Int J Mol Sci 2023; 24:16875. [PMID: 38069200 PMCID: PMC10706123 DOI: 10.3390/ijms242316875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Febrile seizures during early childhood may result in central nervous system developmental disorders. However, the specific mechanisms behind the impact of febrile seizures on the developing brain are not well understood. To address this gap in knowledge, we employed a hyperthermic model of febrile seizures in 10-day-old rats and tracked their development over two months. Our objective was to determine the degree to which the properties of the hippocampal glutamatergic system are modified. We analyzed whether pyramidal glutamatergic neurons in the hippocampus die after febrile seizures. Our findings indicate that there is a reduction in the number of neurons in various regions of the hippocampus in the first two days after seizures. The CA1 field showed the greatest susceptibility, and the reduction in the number of neurons in post-FS rats in this area appeared to be long-lasting. Electrophysiological studies indicate that febrile seizures cause a reduction in glutamatergic transmission, leading to decreased local field potential amplitude. This impairment could be attributable to diminished glutamate release probability as evidenced by decreases in the frequency of miniature excitatory postsynaptic currents and increases in the paired-pulse ratio of synaptic responses. We also found higher threshold current causing hind limb extension in the maximal electroshock seizure threshold test of rats 2 months after febrile seizures compared to the control animals. Our research suggests that febrile seizures can impair glutamatergic transmission, which may protect against future seizures.
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Affiliation(s)
| | | | | | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, Saint Petersburg 194223, Russia; (A.V.G.); (T.Y.P.); (S.L.M.)
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Hlavacova N, Hrivikova K, Karailievova L, Karailiev P, Homberg JR, Jezova D. Altered responsiveness to glutamatergic modulation by MK-801 and to repeated stress of immune challenge in female dopamine transporter knockout rats. Prog Neuropsychopharmacol Biol Psychiatry 2023:110804. [PMID: 37247803 DOI: 10.1016/j.pnpbp.2023.110804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/23/2023] [Accepted: 05/24/2023] [Indexed: 05/31/2023]
Abstract
Chronic stress is a key factor in psychiatric and neurological disorders often worsening disease symptoms. In this study, a unique animal model, the dopamine transporter knockout (DAT-KO) rat exhibiting behavioral signs resembling those occurring in mania, schizophrenia, attention deficit hyperactivity disorder, and obsessive-compulsive disorder was used. We have tested the hypothesis that the hyperdopaminergic state in DAT-KO rats (i) modulates behavioral response to the NMDA antagonist MK-801 (dizocilpine) and (ii) leads to abnormal endocrine and immune activation under subchronic stress induced by an immune challenge. Glutamatergic modulation with MK-801 induced a different behavioral pattern. While the WT rats responded to MK-801 injection with a robust rise in their locomotor activity, the hyperactive DAT-KO rats exhibited reduced locomotion. Signs of chronic stress including increased basal corticosterone and aldosterone but blunted anxiety were demonstrated in rats lacking the DAT. Repeated injections of increasing doses of lipopolysaccharide (LPS, 5 days) did not modify plasma prolactin concentrations which were however significantly lower in DAT-KO than in WT rats. Concentrations of plasma high mobility group box 1 (HMGB1) protein were significantly higher in LPS-treated DAT-KO than in WT rats. The gene expression of interleukin-6 in the anterior pituitary increased under the stress induced by the immune challenge in the WT but not the DAT-KO rats. The most evident differences between the genotypes were revealed in the spleen. The splenic gene expression of interleukin-1β, interleukin-6, and HMGB1 was lower and that of ferritin was higher in DAT-KO compared to WT rats. Obtained results emphasize the functional interaction of the endocrine and immune systems with monoamine and glutamatergic neurotransmission in the mechanisms leading to behavioral alterations and psychiatric disorders associated with dopamine dysfunction.
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Affiliation(s)
- Natasa Hlavacova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia
| | - Katarina Hrivikova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia
| | - Lucia Karailievova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia
| | - Peter Karailiev
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6525 EN Nijmegen, the Netherlands
| | - Daniela Jezova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia.
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3
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Landolfo E, Cutuli D, Decandia D, Balsamo F, Petrosini L, Gelfo F. Environmental Enrichment Protects against Neurotoxic Effects of Lipopolysaccharide: A Comprehensive Overview. Int J Mol Sci 2023; 24:ijms24065404. [PMID: 36982478 PMCID: PMC10049264 DOI: 10.3390/ijms24065404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Neuroinflammation is a pathophysiological condition associated with damage to the nervous system. Maternal immune activation and early immune activation have adverse effects on the development of the nervous system and cognitive functions. Neuroinflammation during adulthood leads to neurodegenerative diseases. Lipopolysaccharide (LPS) is used in preclinical research to mimic neurotoxic effects leading to systemic inflammation. Environmental enrichment (EE) has been reported to cause a wide range of beneficial changes in the brain. Based on the above, the purpose of the present review is to describe the effects of exposure to EE paradigms in counteracting LPS-induced neuroinflammation throughout the lifespan. Up to October 2022, a methodical search of studies in the literature, using the PubMed and Scopus databases, was performed, focusing on exposure to LPS, as an inflammatory mediator, and to EE paradigms in preclinical murine models. On the basis of the inclusion criteria, 22 articles were considered and analyzed in the present review. EE exerts sex- and age-dependent neuroprotective and therapeutic effects in animals exposed to the neurotoxic action of LPS. EE’s beneficial effects are present throughout the various ages of life. A healthy lifestyle and stimulating environments are essential to counteract the damages induced by neurotoxic exposure to LPS.
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Affiliation(s)
- Eugenia Landolfo
- IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Debora Cutuli
- IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
| | - Davide Decandia
- IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
| | - Francesca Balsamo
- IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Department of Human Sciences, Guglielmo Marconi University, Via Plinio 44, 00193 Rome, Italy
| | - Laura Petrosini
- IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
| | - Francesca Gelfo
- IRCCS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Rome, Italy
- Department of Human Sciences, Guglielmo Marconi University, Via Plinio 44, 00193 Rome, Italy
- Correspondence:
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4
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Zubareva OE, Postnikova TY, Grifluk AV, Schwarz AP, Smolensky IV, Karepanov AA, Vasilev DS, Veniaminova EA, Rotov AY, Kalemenev SV, Zaitsev AV. Exposure to bacterial lipopolysaccharidein early life affects the expression of ionotropic glutamate receptor genes and is accompanied by disturbances in long-term potentiation and cognitive functions in young rats. Brain Behav Immun 2020; 90:3-15. [PMID: 32726683 DOI: 10.1016/j.bbi.2020.07.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 01/20/2023] Open
Abstract
Infections in childhood play an essential role in the pathogenesis of cognitive and psycho-emotional disorders. One of the possible mechanisms of these impairments is changes in the functional properties of NMDA and AMPA glutamate receptors in the brain. We suggest that bacterial infections during the early life period, which is critical for excitatory synapse maturation, can affect the subunit composition of NMDA and AMPA receptors. In the present study, we investigated the effect of repetitive lipopolysaccharide (LPS) intraperitoneal (i.p.) administration (25 μg/kg/day on P14, 16, and 18), mimicking an infectious disease, on the expression of subunits of NMDA and AMPA receptors in young rats. We revealed a substantial decrease of GluN2B subunit expression in the hippocampus at P23 using Western blot analysis and real-time polymerase chain reaction assay. Moderate changes were also found in GluN1, GluN2A, and GluA1 mRNA expression. The LPS-treated rats exhibited decreased exploratory and locomotor activity in the open field test and the impairment of spatial learning in the Morris water maze. Behavioral impairments were accompanied by a significant reduction in long-term hippocampal synaptic potentiation. Our data indicate that LPS-treatment in the critical period for excitatory synapse maturation alters ionotropic glutamate receptor gene expression, disturbs synaptic plasticity, and alters behavior.
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Affiliation(s)
- Olga E Zubareva
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia; Laboratory of Neurobiology of the Brain Integrative Functions, Pavlov Department of Physiology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - Tatyana Y Postnikova
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexandra V Grifluk
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander P Schwarz
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Ilya V Smolensky
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Anton A Karepanov
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Dmitry S Vasilev
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Ekaterina A Veniaminova
- Laboratory of Neurobiology of the Brain Integrative Functions, Pavlov Department of Physiology, Institute of Experimental Medicine, St. Petersburg, Russia
| | - Alexander Y Rotov
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Sergey V Kalemenev
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Aleksey V Zaitsev
- Laboratory of Molecular Mechanisms of Neuronal Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
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Smail MA, Smith BL, Nawreen N, Herman JP. Differential impact of stress and environmental enrichment on corticolimbic circuits. Pharmacol Biochem Behav 2020; 197:172993. [PMID: 32659243 PMCID: PMC7484282 DOI: 10.1016/j.pbb.2020.172993] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 05/27/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022]
Abstract
Stress exposure can produce profound changes in physiology and behavior that can impair health and well-being. Of note, stress exposure is linked to anxiety disorders and depression in humans. The widespread impact of these disorders warrants investigation into treatments to mitigate the harmful effects of stress. Pharmacological treatments fail to help many with these disorders, so recent work has focused on non-pharmacological alternatives. One of the most promising of these alternatives is environmental enrichment (EE). In rodents, EE includes social, physical, and cognitive stimulation for the animal, in the form of larger cages, running wheels, and toys. EE successfully reduces the maladaptive effects of various stressors, both as treatment and prophylaxis. While we know that EE can have beneficial effects under stress conditions, the morphological and molecular mechanisms underlying these behavioral effects are still not well understood. EE is known to alter neurogenesis, dendrite development, and expression of neurotrophic growth factors, effects that vary by type of enrichment, age, and sex. To add to this complexity, EE has differential effects in different brain regions. Understanding how EE exerts its protective effects on morphological and molecular levels could hold the key to developing more targeted pharmacological treatments. In this review, we summarize the literature on the morphological and molecular consequences of EE and stress in key emotional regulatory pathways in the brain, the hippocampus, prefrontal cortex, and amygdala. The similarities and differences among these regions provide some insight into stress-EE interaction that may be exploited in future efforts toward prevention of, and intervention in, stress-related diseases.
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Affiliation(s)
- Marissa A Smail
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States; Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States.
| | - Brittany L Smith
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States
| | - Nawshaba Nawreen
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States; Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States
| | - James P Herman
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States; Veterans Affairs Medical Center, Cincinnati, OH, United States; Department of Neurology, University of Cincinnati, Cincinnati, OH, United States
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6
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Singhal G, Morgan J, Jawahar MC, Corrigan F, Jaehne EJ, Toben C, Breen J, Pederson SM, Manavis J, Hannan AJ, Baune BT. Effects of aging on the motor, cognitive and affective behaviors, neuroimmune responses and hippocampal gene expression. Behav Brain Res 2020; 383:112501. [PMID: 31987935 DOI: 10.1016/j.bbr.2020.112501] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 01/21/2020] [Accepted: 01/21/2020] [Indexed: 12/15/2022]
Abstract
The known effects of aging on the brain and behavior include impaired cognition, increases in anxiety and depressive-like behaviors, and reduced locomotor activity. Environmental exposures and interventions also influence brain functions during aging. We investigated the effects of normal aging under controlled environmental conditions and in the absence of external interventions on locomotor activity, cognition, anxiety and depressive-like behaviors, immune function and hippocampal gene expression in C57BL/6 mice. Healthy mice at 4, 9, and 14 months of age underwent behavioral testing using an established behavioral battery, followed by cellular and molecular analysis using flow cytometry, immunohistochemistry, and quantitative PCR. We found that 14-month-old mice showed significantly reduced baseline locomotion, increased anxiety, and impaired spatial memory compared to younger counterparts. However, no significant differences were observed for depressive-like behavior in the forced-swim test. Microglia numbers in the dentate gyrus, as well as CD8+ memory T cells increased towards late middle age. Aging processes exerted a significant effect on the expression of 43 genes of interest in the hippocampus. We conclude that aging is associated with specific changes in locomotor activity, cognition, anxiety-like behaviors, neuroimmune responses and hippocampal gene expression.
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Affiliation(s)
- Gaurav Singhal
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia.
| | - Julie Morgan
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia.
| | - Magdalene C Jawahar
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia.
| | - Frances Corrigan
- Division of Health Sciences, The University of South Australia, Adelaide, SA, Australia.
| | - Emily J Jaehne
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia; School of Psychology and Public Health, LIMS2, Room 204, La Trobe University, Bundoora, Melbourne, Vic, Australia.
| | - Catherine Toben
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, The University of Adelaide, Adelaide, SA, Australia.
| | - James Breen
- Robinson Research Institute, The University of Adelaide, SA, Australia; Bioinformatics Hub, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia.
| | - Stephen M Pederson
- Bioinformatics Hub, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia.
| | - Jim Manavis
- Centre for Neurological Diseases, School of Medicine, Faculty of Health, The University of Adelaide, Adelaide, SA, Australia.
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia.
| | - Bernhard T Baune
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia; Department of Psychiatry, Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia; Department of Psychiatry, University of Münster, Münster, Germany.
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7
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Therapeutic efficacy of environmental enrichment for substance use disorders. Pharmacol Biochem Behav 2019; 188:172829. [PMID: 31778722 DOI: 10.1016/j.pbb.2019.172829] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/18/2022]
Abstract
Addiction to drug and alcohol is regarded as a major health problem worldwide for which available treatments show limited effectiveness. The biggest challenge remains to enhance the capacities of interventions to reduce craving, prevent relapse and promote long-term recovery. New strategies to meet these challenges are being explored. Findings from preclinical work suggest that environmental enrichment (EE) holds therapeutic potential for the treatment of substance use disorders, as demonstrated in a number of animal models of drug abuse. The EE intervention introduced after drug exposure leads to attenuation of compulsive drug taking, attenuation of the rewarding (and reinforcing) effects of drugs, reductions in control of behavior by drug cues, and, very importantly, relapse prevention. Clinical work also suggests that multidimensional EE interventions (involving physical activity, social interaction, vocational training, recreational and community involvement) might produce similar therapeutic effects, if implemented continuously and rigorously. In this review we survey preclinical and clinical studies assessing the efficacy of EE as a behavioral intervention for substance use disorders and address related challenges. We also review work providing empirical evidence for EE-induced neuroplasticity within the mesocorticolimbic system that is believed to contribute to the seemingly therapeutic effects of EE on drug and alcohol-related behaviors.
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Short-term environmental enrichment, and not physical exercise, alleviate cognitive decline and anxiety from middle age onwards without affecting hippocampal gene expression. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2019; 19:1143-1169. [DOI: 10.3758/s13415-019-00743-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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9
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Schoemaker D, Buss C, Pietrantonio S, Maunder L, Freiesleben SD, Hartmann J, Collins DL, Lupien S, Pruessner JC. The hippocampal-to-ventricle ratio (HVR): Presentation of a manual segmentation protocol and preliminary evidence. Neuroimage 2019; 203:116108. [PMID: 31472249 DOI: 10.1016/j.neuroimage.2019.116108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 08/13/2019] [Accepted: 08/17/2019] [Indexed: 12/31/2022] Open
Abstract
Disentangling age-related changes from developmental variations in hippocampal volume has proven challenging. This article presents a manual segmentation protocol for the hippocampal-to-ventricle ratio (HVR), a measure combining the assessment of hippocampal volume with surrounding ventricular volume. By providing in a single measure both a standard volumetric assessment of the hippocampus and an approximation of volume loss, based on ventricular enlargement, we believe the HVR provides a superior cross-sectional estimation of hippocampal structural integrity. In a first attempt to validate this measure, we contrasted the HVR and standard hippocampal volume in their associations with age and memory performance in two independent cohorts of healthy aging individuals. The first cohort consisted in 50 cognitively normal subjects (mean age: 66.8 years, SD: 4.96, range: 60-75 years), while the second cohort included 88 cognitively normal subjects (mean age: 65.06 years, SD: 6.42, range: 55-80 years). We showed that the manual segmentation protocol for the HVR can be implemented with high reliability. In both cohorts, the HVR showed stronger negative associations with age than standard hippocampal volume. Correlations with memory performance were also numerically superior with the HVR than standard hippocampal volume, across the two cohorts. These findings support an added benefit of using the HVR over standard hippocampal volume when examining relationships with age or memory function in aging individuals. Although further validation is required, we propose that the computation of the HVR is a promising method to improve the evaluation of hippocampal integrity from cross-sectional MR images.
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Affiliation(s)
- Dorothee Schoemaker
- Massachusetts General Hospital, Harvard Medical School, Boston, USA; McGill Centre for Studies in Aging & Douglas Mental Health Institute, Faculty of Medicine, McGill University, Montreal, Canada
| | - Claudia Buss
- Department of Psychology, Charite Berlin, Berlin, Germany
| | - Sandra Pietrantonio
- McGill Centre for Studies in Aging & Douglas Mental Health Institute, Faculty of Medicine, McGill University, Montreal, Canada
| | - Larah Maunder
- Department of Psychology, Queen's University, Kingston, Canada
| | - Silka Dawn Freiesleben
- McGill Centre for Studies in Aging & Douglas Mental Health Institute, Faculty of Medicine, McGill University, Montreal, Canada
| | - Johanna Hartmann
- Department of Psychology, University of Constance, Constance, Germany
| | - D Louis Collins
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Sonia Lupien
- Centre for Studies on Human Stress, Montreal Mental Health University Institute, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Jens C Pruessner
- McGill Centre for Studies in Aging & Douglas Mental Health Institute, Faculty of Medicine, McGill University, Montreal, Canada; Department of Psychology, University of Constance, Constance, Germany.
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10
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Zajac MS, Renoir T, Perreau VM, Li S, Adams W, van den Buuse M, Hannan AJ. Short-Term Environmental Stimulation Spatiotemporally Modulates Specific Serotonin Receptor Gene Expression and Behavioral Pharmacology in a Sexually Dimorphic Manner in Huntington's Disease Transgenic Mice. Front Mol Neurosci 2018; 11:433. [PMID: 30618600 PMCID: PMC6295568 DOI: 10.3389/fnmol.2018.00433] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 11/08/2018] [Indexed: 11/29/2022] Open
Abstract
Huntington’s disease (HD) is a neurodegenerative disorder caused by a tandem repeat mutation encoding an expanded polyglutamine tract in the huntingtin protein, which leads to cognitive, psychiatric and motor dysfunction. Exposure to environmental enrichment (EE), which enhances levels of cognitive stimulation and physical activity, has therapeutic effects on cognitive, affective and motor function of transgenic HD mice. The present study investigated gene expression changes and behavioral pharmacology in male and female R6/1 transgenic HD mice at an early time-point in HD progression associated with onset of cognitive and affective abnormalities, following EE and exercise (wheel running) interventions. We have demonstrated changes in expression levels of the serotonin (5-HT) receptor Htr1a, Htr1b, Htr2a and Htr2c genes (encoding the 5-HT1A, 5-HT1B, 5-HT2A and 5-HT2C receptors, respectively) in HD brains at 8 weeks of age, using quantitative real-time PCR. In contrast, expression of the serotonin transporter (SerT, also known as 5-HTT or Slc6a4) was not altered in these brains. Furthermore, we identified region-specific, sex-specific and environmentally regulated (comparing EE, exercise and standard housing conditions) impacts on gene expression of particular 5-HT receptors, as well as SerT. For example, SerT gene expression was upregulated by exercise (wheel running from 6 to 8 weeks of age) in the hippocampus. Interestingly, when EE was introduced from 6 to 8 weeks of age, Htr2a gene expression was upregulated in the cortex, striatum and hippocampus of male mice. EE also rescued the functional activity of 5-HT2 receptors as observed in the head-twitch test, reflecting sexually dimorphic effects of environmental stimulation. These findings demonstrate that disruption of the serotonergic system occurs early in HD pathogenesis and, together with previous findings, show that the timing and duration of environmental interventions are critical in terms of their ability to modify gene expression. This study is the first to show that EE is able to selectively enhance both gene expression of a neurotransmitter receptor and the functional consequences on behavioral pharmacology, and links this molecular modulation to the therapeutic effects of environmental stimulation in this neurodegenerative disease.
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Affiliation(s)
- Michelle S Zajac
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Thibault Renoir
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Victoria M Perreau
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Shanshan Li
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Wendy Adams
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia.,Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Maarten van den Buuse
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia.,School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
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11
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Cope EC, Opendak M, LaMarca EA, Murthy S, Park CY, Olson LB, Martinez S, Leung JM, Graham AL, Gould E. The effects of living in an outdoor enclosure on hippocampal plasticity and anxiety-like behavior in response to nematode infection. Hippocampus 2018; 29:366-377. [PMID: 30252982 DOI: 10.1002/hipo.23033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/23/2018] [Accepted: 09/20/2018] [Indexed: 12/17/2022]
Abstract
The hippocampus of rodents undergoes structural remodeling throughout adulthood, including the addition of new neurons. Adult neurogenesis is sensitive to environmental enrichment and stress. Microglia, the brain's resident immune cells, are involved in adult neurogenesis by engulfing dying new neurons. While previous studies using laboratory environmental enrichment have investigated alterations in brain structure and function, they do not provide an adequate reflection of living in the wild, in which stress and environmental instability are common. Here, we compared mice living in standard laboratory settings to mice living in outdoor enclosures to assess the complex interactions among environment, gut infection, and hippocampal plasticity. We infected mice with parasitic worms and studied their effects on adult neurogenesis, microglia, and functions associated with the hippocampus, including cognition and anxiety regulation. We found an increase in immature neuron numbers of mice living in outdoor enclosures regardless of infection. While outdoor living prevented increases in microglial reactivity induced by infection in both the dorsal and ventral hippocampus, outdoor mice with infection had fewer microglia and microglial processes in the ventral hippocampus. We observed no differences in cognitive performance on the hippocampus-dependent object location task between infected and uninfected mice living in either setting. However, we found that infection caused an increase in anxiety-like behavior in the open field test but only in outdoor mice. These findings suggest that living conditions, as well as gut infection, interact to produce complex effects on brain structure and function.
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Affiliation(s)
- Elise C Cope
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Maya Opendak
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Elizabeth A LaMarca
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Sahana Murthy
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Christin Y Park
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Lyra B Olson
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Susana Martinez
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
| | - Jacqueline M Leung
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
| | - Andrea L Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
| | - Elizabeth Gould
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, New Jersey
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12
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Aujnarain AB, Luo OD, Taylor N, Lai JKY, Foster JA. Effects of exercise and enrichment on behaviour in CD-1 mice. Behav Brain Res 2018; 342:43-50. [PMID: 29339005 DOI: 10.1016/j.bbr.2018.01.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/26/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022]
Abstract
A host of scholarly work has characterized the positive effects of exercise and environmental enrichment on behaviour and cognition in animal studies. The purpose of this study was to investigate the uptake and longitudinal impact of exercise and enrichment on the behavioural phenotype of male and female CD-1 mice. CD-1 mice housed in standard (STD) or exercise and enrichment (EE) conditions post-weaning were tested in the 3-chamber sociability test, open field, and elevated plus maze and exercise activity was monitored throughout the enrichment protocol. Male and female EE mice both showed reduced anxiety and activity in the open field and elevated plus maze relative to sex-matched STD mice. EE altered social behaviours in a sex-specific fashion, with only female EE mice showing increased social preference relative to female STD mice and a preference for social novelty only present in male EE mice. This sexual dimorphism was not observed to be a product of exercise uptake, as CD-1 mice of both sexes demonstrated a consistent trend of wheel rotation frequencies. These findings suggest the importance of considering variables such as sex and strain on experimental design variables in future work on environmental enrichment.
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Affiliation(s)
- Amiirah B Aujnarain
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
| | - Owen D Luo
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
| | - Natalie Taylor
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
| | - Jonathan K Y Lai
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada
| | - Jane A Foster
- Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, Ontario, Canada; Department of Psychiatry, St. Michael's Hospital, Toronto, Ontario, Canada.
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13
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Csanova A, Hlavacova N, Hasiec M, Pokusa M, Prokopova B, Jezova D. β 3-Adrenergic receptors, adipokines and neuroendocrine activation during stress induced by repeated immune challenge in male and female rats. Stress 2017; 20:294-302. [PMID: 28412873 DOI: 10.1080/10253890.2017.1320387] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The main hypothesis of the study is that stress associated with repeated immune challenge has an impact on β3-adrenergic receptor gene expression in the brain. Sprague-Dawley rats were intraperitoneally injected with increasing doses of lipopolysaccharide (LPS) for five consecutive days. LPS treatment was associated with body weight loss and increased anxiety-like behavior. In LPS-treated animals of both sexes, β3-receptor gene expression was increased in the prefrontal cortex but not the hippocampus. LPS treatment decreased β3-receptor gene expression in white adipose tissue with higher values in males compared to females. In the adipose tissue, LPS reduced peroxisome proliferator-activated receptor-gamma, leptin and adiponectin gene expression, but increased interleukin-6 expression, irrespective of sex. Repeated immune challenge resulted in increased concentrations of plasma aldosterone and corticosterone with higher values of corticosterone in females compared to males. Concentrations of dehydroepiandrosterone (DHEA) in plasma were unaffected by LPS, while DHEA levels in the frontal cortex were lower in the LPS-treated animals compared to the controls. Thus, changes of DHEA levels in the brain take place irrespective of the changes of this neurosteroid in plasma. We have provided the first evidence on stress-induced increase in β3-adrenergic receptor gene expression in the brain. Greater reduction of β3-adrenergic receptor expression in the adipose tissue and of the body weight gain by repeated immune challenge in male than in female rats suggests sex differences in the role of β3-adrenergic receptors in the metabolic functions. LPS-induced changes in adipose tissue regulatory factors and hormone concentrations might be important for coping with chronic infections.
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Affiliation(s)
- Agnesa Csanova
- a Laboratory of Pharmacological Neuroendocrinology , Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences , Bratislava , Slovak Republic
| | - Natasa Hlavacova
- a Laboratory of Pharmacological Neuroendocrinology , Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences , Bratislava , Slovak Republic
| | - Malgorzata Hasiec
- b The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences , Jablonna , Poland
| | - Michal Pokusa
- a Laboratory of Pharmacological Neuroendocrinology , Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences , Bratislava , Slovak Republic
| | - Barbora Prokopova
- a Laboratory of Pharmacological Neuroendocrinology , Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences , Bratislava , Slovak Republic
- c Faculty of Pharmacy , Comenius University in Bratislava , Slovak Republic
| | - Daniela Jezova
- a Laboratory of Pharmacological Neuroendocrinology , Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences , Bratislava , Slovak Republic
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14
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Kim MS, Yu JH, Kim CH, Choi JY, Seo JH, Lee MY, Yi CH, Choi TH, Ryu YH, Lee JE, Lee BH, Kim H, Cho SR. Environmental enrichment enhances synaptic plasticity by internalization of striatal dopamine transporters. J Cereb Blood Flow Metab 2016; 36:2122-2133. [PMID: 26661218 PMCID: PMC5363660 DOI: 10.1177/0271678x15613525] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 09/20/2015] [Accepted: 09/21/2015] [Indexed: 12/20/2022]
Abstract
Environmental enrichment (EE) with a complex combination of physical, cognitive and social stimulations enhances synaptic plasticity and behavioral function. However, the mechanism remains to be elucidated in detail. We aimed to investigate dopamine-related synaptic plasticity underlying functional improvement after EE. For this, six-week-old CD-1 mice were randomly allocated to EE or standard conditions for two months. EE significantly enhanced behavioral functions such as rotarod and ladder walking tests. In a [18F]FPCIT positron emission tomography scan, binding values of striatal DAT were significantly decreased approximately 18% in the EE mice relative to the control mice. DAT inhibitor administrated to establish the relationship of the DAT down-regulation to the treatment effects also improved rotarod performances, suggesting that DAT inhibition recapitulated EE-mediated treatment benefits. Next, EE-induced internalization of DAT was confirmed using a surface biotinylation assay. In situ proximity ligation assay and immunoprecipitation demonstrated that EE significantly increased the phosphorylation of striatal DAT as well as the levels of DAT bound with protein kinase C (PKC). In conclusion, we suggest that EE enables phosphorylation of striatal DAT via a PKC-mediated pathway and causes DAT internalization. This is the first report to suggest an EE-mediated mechanism of synaptic plasticity by internalization of striatal DAT.
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Affiliation(s)
- Myung-Sun Kim
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.,Yonsei Stem Cell Center, Avison Biomedical Research Center, Seoul, Korea
| | - Ji Hea Yu
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.,Department of Medical Science, The Graduate School, Yonsei University, Seoul, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
| | - Chul Hoon Kim
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea.,Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea.,Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jae Yong Choi
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea.,Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Jung Hwa Seo
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
| | - Min-Young Lee
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.,Yonsei Stem Cell Center, Avison Biomedical Research Center, Seoul, Korea
| | - Chi Hoon Yi
- Department of Molecular Imaging, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Tae Hyun Choi
- Department of Molecular Imaging, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Jong Eun Lee
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea.,Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.,Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
| | - Bae Hwan Lee
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea.,Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.,Department of Physiology, Yonsei University College of Medicine, Seoul, Korea
| | - Hyongbum Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Korea
| | - Sung-Rae Cho
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea .,Yonsei Stem Cell Center, Avison Biomedical Research Center, Seoul, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea.,Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
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15
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Yu JH, Kim M, Seo JH, Cho SR. Brain Plasticity and Neurorestoration by Environmental Enrichment. BRAIN & NEUROREHABILITATION 2016. [DOI: 10.12786/bn.2016.9.e2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ji Hea Yu
- Department of Rehabilitation Medicine and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
- Yonsei Stem Cell Center, Avison Biomedical Research Center, Seoul, Korea
| | - MinGi Kim
- Department of Rehabilitation Medicine and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
| | - Jung Hwa Seo
- Department of Rehabilitation Medicine and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
| | - Sung-Rae Cho
- Department of Rehabilitation Medicine and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea
- Yonsei Stem Cell Center, Avison Biomedical Research Center, Seoul, Korea
- Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, Korea
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16
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Zanca RM, Braren SH, Maloney B, Schrott LM, Luine VN, Serrano PA. Environmental Enrichment Increases Glucocorticoid Receptors and Decreases GluA2 and Protein Kinase M Zeta (PKMζ) Trafficking During Chronic Stress: A Protective Mechanism? Front Behav Neurosci 2015; 9:303. [PMID: 26617502 PMCID: PMC4642137 DOI: 10.3389/fnbeh.2015.00303] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/29/2015] [Indexed: 12/15/2022] Open
Abstract
Environmental enrichment (EE) housing paradigms have long been shown beneficial for brain function involving neural growth and activity, learning and memory capacity, and for developing stress resiliency. The expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA2, which is important for synaptic plasticity and memory, is increased with corticosterone (CORT), undermining synaptic plasticity and memory. Thus, we determined the effect of EE and stress on modulating GluA2 expression in Sprague-Dawley male rats. Several markers were evaluated which include: plasma CORT, the glucocorticoid receptor (GR), GluA2, and the atypical protein kinase M zeta (PKMζ). For 1 week standard-(ST) or EE-housed animals were treated with one of the following four conditions: (1) no stress; (2) acute stress (forced swim test, FST; on day 7); (3) chronic restraint stress (6 h/day for 7 days); and (4) chronic + acute stress (restraint stress 6 h/day for 7 days + FST on day 7). Hippocampi were collected on day 7. Our results show that EE animals had reduced time immobile on the FST across all conditions. After chronic + acute stress EE animals showed increased GR levels with no change in synaptic GluA2/PKMζ. ST-housed animals showed the reverse pattern with decreased GR levels and a significant increase in synaptic GluA2/PKMζ. These results suggest that EE produces an adaptive response to chronic stress allowing for increased GR levels, which lowers neuronal excitability reducing GluA2/PKMζ trafficking. We discuss this EE adaptive response to stress as a potential underlying mechanism that is protective for retaining synaptic plasticity and memory function.
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Affiliation(s)
- Roseanna M Zanca
- Department of Psychology, Hunter College City University of New York, New York, NY, USA
| | - Stephen H Braren
- Department of Psychology, Hunter College City University of New York, New York, NY, USA
| | - Brigid Maloney
- Department of Psychology, Hunter College City University of New York, New York, NY, USA
| | - Lisa M Schrott
- Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center Shreveport, LA, USA
| | - Victoria N Luine
- Department of Psychology, Hunter College City University of New York, New York, NY, USA ; The Graduate Center of CUNY New York, NY, USA
| | - Peter A Serrano
- Department of Psychology, Hunter College City University of New York, New York, NY, USA ; The Graduate Center of CUNY New York, NY, USA
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17
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Hamed MR, Hassanein NMA, Zaquqe SAM, Mousa AAR. Impact of certain immunomodulators on LPS-induced hematotoxicity. Med Chem Res 2015. [DOI: 10.1007/s00044-015-1374-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Huzard D, Mumby DG, Sandi C, Poirier GL, van der Kooij MA. The effects of extrinsic stress on somatic markers and behavior are dependent on animal housing conditions. Physiol Behav 2015. [PMID: 26220463 DOI: 10.1016/j.physbeh.2015.07.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Properties of the environment play an important role in animal wellbeing and may modulate the effects of external threats. Whereas stressors can affect emotion and impair cognition, environmental enrichment may prevent the occurrence of such negative sequelae. Animals exposed to semi-natural group-housing experience a complex environment; whereas environmental enrichment might protect against stressors, a socially-enriched environment(SEE) could entail aggressive inter-male encounters with additive stress effects. In the present study, we investigated the effects of exposure to external stressors, footshocks and forced swimming, on adrenal gland and body weights as well as on behavior in rats housed under SEE or standard, non-enriched environment (NEE), conditions. We found that SEEs reduced the anxiogenic effects of stress. Moreover, SEEs improved the performance in an operant task and prevented the increase in impulsive behavior produced by external stressors on NEE animals. Whereas these findings are indicative of stress-buffering effects of SEEs, adrenal gland weights were increased while total body weights were decreased in SEE rats, suggesting that SEEs may simultaneously exacerbate physiological measurements of stress. Finally, in the SEE, total aggressive behaviors and body wounds were paradoxically reduced in animals that received external stressors in comparison to non-stressed controls. The consequences of the external stressors applied here are not uniform, varying according to the housing condition and the outcome considered.
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Affiliation(s)
- Damien Huzard
- Laboratory of Behavioral Genetics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada
| | - Dave G Mumby
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada
| | - Carmen Sandi
- Laboratory of Behavioral Genetics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Guillaume L Poirier
- Laboratory of Behavioral Genetics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Michael A van der Kooij
- Laboratory of Behavioral Genetics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.
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19
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Crofton EJ, Zhang Y, Green TA. Inoculation stress hypothesis of environmental enrichment. Neurosci Biobehav Rev 2015; 49:19-31. [PMID: 25449533 PMCID: PMC4305384 DOI: 10.1016/j.neubiorev.2014.11.017] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/28/2014] [Accepted: 11/21/2014] [Indexed: 01/28/2023]
Abstract
One hallmark of psychiatric conditions is the vast continuum of individual differences in susceptibility vs. resilience resulting from the interaction of genetic and environmental factors. The environmental enrichment paradigm is an animal model that is useful for studying a range of psychiatric conditions, including protective phenotypes in addiction and depression models. The major question is how environmental enrichment, a non-drug and non-surgical manipulation, can produce such robust individual differences in such a wide range of behaviors. This paper draws from a variety of published sources to outline a coherent hypothesis of inoculation stress as a factor producing the protective enrichment phenotypes. The basic tenet suggests that chronic mild stress from living in a complex environment and interacting non-aggressively with conspecifics can inoculate enriched rats against subsequent stressors and/or drugs of abuse. This paper reviews the enrichment phenotypes, mulls the fundamental nature of environmental enrichment vs. isolation, discusses the most appropriate control for environmental enrichment, and challenges the idea that cortisol/corticosterone equals stress. The intent of the inoculation stress hypothesis of environmental enrichment is to provide a scaffold with which to build testable hypotheses for the elucidation of the molecular mechanisms underlying these protective phenotypes and thus provide new therapeutic targets to treat psychiatric/neurological conditions.
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Affiliation(s)
- Elizabeth J Crofton
- Center for Addiction Research, Mitchell Center for Neurodegenerative Diseases, Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, United States
| | - Yafang Zhang
- Center for Addiction Research, Mitchell Center for Neurodegenerative Diseases, Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, United States
| | - Thomas A Green
- Center for Addiction Research, Mitchell Center for Neurodegenerative Diseases, Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, United States.
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20
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Zhang Y, Crofton EJ, Li D, Lobo MK, Fan X, Nestler EJ, Green TA. Overexpression of DeltaFosB in nucleus accumbens mimics the protective addiction phenotype, but not the protective depression phenotype of environmental enrichment. Front Behav Neurosci 2014; 8:297. [PMID: 25221490 PMCID: PMC4148937 DOI: 10.3389/fnbeh.2014.00297] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 08/13/2014] [Indexed: 11/13/2022] Open
Abstract
Environmental enrichment produces protective addiction and depression phenotypes in rats. ΔFosB is a transcription factor that regulates reward in the brain and is induced by psychological stress as well as drugs of abuse. However, the role played by ΔFosB in the protective phenotypes of environmental enrichment has not been well studied. Here, we demonstrate that ΔFosB is differentially regulated in rats reared in an isolated condition (IC) compared to those in an enriched condition (EC) in response to restraint stress or cocaine. Chronic stress or chronic cocaine treatment each elevates ΔFosB protein levels in the nucleus accumbens (NAc) of IC rats, but not of EC rats due to an already elevated basal accumulation of ΔFosB seen under EC conditions. Viral-mediated overexpression of ΔFosB in the NAc shell of pair-housed rats (i.e., independent of environmental enrichment/isolation) increases operant responding for sucrose when motivated by hunger, but decreases responding in satiated animals. Moreover, ΔFosB overexpression decreases cocaine self-administration, enhances extinction of cocaine seeking, and decreases cocaine-induced reinstatement of intravenous cocaine self-administration; all behavioral findings consistent with the enrichment phenotype. In contrast, however, ΔFosB overexpression did not alter responses of pair-housed rats in several tests of anxiety- and depression-related behavior. Thus, ΔFosB in the NAc the shell mimics the protective addiction phenotype, but not the protective depression phenotype of environmental enrichment.
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Affiliation(s)
- Yafang Zhang
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA
| | - Elizabeth J Crofton
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA
| | - Dingge Li
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA
| | - Mary Kay Lobo
- Anatomy and Neurobiology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Xiuzhen Fan
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA
| | - Eric J Nestler
- Neuroscience, Mount Sinai School of Medicine New York, NY, USA
| | - Thomas A Green
- Center for Addiction Research, Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA
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Sale A, Berardi N, Maffei L. Environment and Brain Plasticity: Towards an Endogenous Pharmacotherapy. Physiol Rev 2014; 94:189-234. [DOI: 10.1152/physrev.00036.2012] [Citation(s) in RCA: 265] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Brain plasticity refers to the remarkable property of cerebral neurons to change their structure and function in response to experience, a fundamental theoretical theme in the field of basic research and a major focus for neural rehabilitation following brain disease. While much of the early work on this topic was based on deprivation approaches relying on sensory experience reduction procedures, major advances have been recently obtained using the conceptually opposite paradigm of environmental enrichment, whereby an enhanced stimulation is provided at multiple cognitive, sensory, social, and motor levels. In this survey, we aim to review past and recent work concerning the influence exerted by the environment on brain plasticity processes, with special emphasis on the underlying cellular and molecular mechanisms and starting from experimental work on animal models to move to highly relevant work performed in humans. We will initiate introducing the concept of brain plasticity and describing classic paradigmatic examples to illustrate how changes at the level of neuronal properties can ultimately affect and direct key perceptual and behavioral outputs. Then, we describe the remarkable effects elicited by early stressful conditions, maternal care, and preweaning enrichment on central nervous system development, with a separate section focusing on neurodevelopmental disorders. A specific section is dedicated to the striking ability of environmental enrichment and physical exercise to empower adult brain plasticity. Finally, we analyze in the last section the ever-increasing available knowledge on the effects elicited by enriched living conditions on physiological and pathological aging brain processes.
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Affiliation(s)
- Alessandro Sale
- Institute of Neuroscience, National Research Council, Pisa, Italy; Department of Psychology, Florence University, Florence, Italy; and Scuola Normale Superiore, Pisa, Italy
| | - Nicoletta Berardi
- Institute of Neuroscience, National Research Council, Pisa, Italy; Department of Psychology, Florence University, Florence, Italy; and Scuola Normale Superiore, Pisa, Italy
| | - Lamberto Maffei
- Institute of Neuroscience, National Research Council, Pisa, Italy; Department of Psychology, Florence University, Florence, Italy; and Scuola Normale Superiore, Pisa, Italy
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22
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Yang X, Goh A, Chen SHA, Qiu A. Evolution of hippocampal shapes across the human lifespan. Hum Brain Mapp 2013; 34:3075-85. [PMID: 22815197 PMCID: PMC6870440 DOI: 10.1002/hbm.22125] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 03/20/2012] [Accepted: 04/20/2012] [Indexed: 11/10/2022] Open
Abstract
Aberrant hippocampal morphology plays an important role in the pathophysiology of aging. Volumetric analysis of the hippocampus has been performed in aging studies; however, the shape morphometry--which is potentially more informative in terms of related cognition--has yet to be examined. In this paper, we employed an advanced brain mapping technique, large deformation diffeomorphic metric mapping (LDDMM), and a dimensionality reduction approach, locally linear diffeomorphic metric embedding (LLDME), to explore age-related changes in hippocampal shape as delineated from magnetic resonance (MR) images of 302 healthy adults aged from 18 to 94 years. Compared with the hippocampal volumes, the hippocampal shapes clearly showed the nonlinear trajectory of biological aging across the human lifespan, where the variation of hippocampal shapes by age was characterized by a cubic polynomial. By integrating of LDDMM and LLDME, we were also able to illustrate the average hippocampal shapes in each individual decade. In addition, LDDMM and LLDME facilitated the identification of 63 years as a threshold beyond which hippocampal morphological changes were accelerated. Adults over 63 years of age showed the inward-deformation bilaterally in the head of the hippocampi and the left subiculum regardless of hippocampal volume reduction when compared to adults younger than 63. Hence, we demonstrated that the shape of anatomical structures added another dimension of structural morphological quantification beyond the volume in understanding aging.
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Affiliation(s)
- Xianfeng Yang
- Department of Bioengineering, National University of Singapore, Singapore, Singapore
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23
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Zhong L, Yan CH, Lu CQ, Xu J, Huang H, Shen XM. Calmodulin activation is required for the enhancement of hippocampal neurogenesis following environmental enrichment. Neurol Res 2013; 31:707-13. [DOI: 10.1179/174313209x380856] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Lee MY, Yu JH, Kim JY, Seo JH, Park ES, Kim CH, Kim H, Cho SR. Alteration of synaptic activity-regulating genes underlying functional improvement by long-term exposure to an enriched environment in the adult brain. Neurorehabil Neural Repair 2013; 27:561-74. [PMID: 23558143 DOI: 10.1177/1545968313481277] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Housing animals in an enriched environment (EE) enhances behavioral function. However, the mechanism underlying this EE-mediated functional improvement and the resultant changes in gene expression have yet to be elucidated. OBJECTIVES We attempted to investigate the underlying mechanisms associated with long-term exposure to an EE by evaluating gene expression patterns. METHODS We housed 6-week-old CD-1 (ICR) mice in standard cages or an EE comprising a running wheel, novel objects, and social interaction for 2 months. Motor and cognitive performances were evaluated using the rotarod test and passive avoidance test, and gene expression profile was investigated in the cerebral hemispheres using microarray and gene set enrichment analysis (GSEA). RESULTS In behavioral assessment, an EE significantly enhanced rotarod performance and short-term working memory. Microarray analysis revealed that genes associated with neuronal activity were significantly altered by an EE. GSEA showed that genes involved in synaptic transmission and postsynaptic signal transduction were globally upregulated, whereas those associated with reuptake by presynaptic neurotransmitter transporters were downregulated. In particular, both microarray and GSEA demonstrated that EE exposure increased opioid signaling, acetylcholine release cycle, and postsynaptic neurotransmitter receptors but decreased Na+ / Cl- -dependent neurotransmitter transporters, including dopamine transporter Slc6a3 in the brain. Western blotting confirmed that SLC6A3, DARPP32 (PPP1R1B), and P2RY12 were largely altered in a region-specific manner. CONCLUSION An EE enhanced motor and cognitive function through the alteration of synaptic activity-regulating genes, improving the efficient use of neurotransmitters and synaptic plasticity by the upregulation of genes associated with postsynaptic receptor activity and downregulation of presynaptic reuptake by neurotransmitter transporters.
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Affiliation(s)
- Min-Young Lee
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea
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Pritchard L, Van Kempen T, Zimmerberg B. Behavioral effects of repeated handling differ in rats reared in social isolation and environmental enrichment. Neurosci Lett 2013; 536:47-51. [DOI: 10.1016/j.neulet.2012.12.048] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/23/2012] [Accepted: 12/27/2012] [Indexed: 11/28/2022]
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Garrido P, De Blas M, Ronzoni G, Cordero I, Antón M, Giné E, Santos A, Del Arco A, Segovia G, Mora F. Differential effects of environmental enrichment and isolation housing on the hormonal and neurochemical responses to stress in the prefrontal cortex of the adult rat: relationship to working and emotional memories. J Neural Transm (Vienna) 2012; 120:829-43. [DOI: 10.1007/s00702-012-0935-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 11/29/2012] [Indexed: 12/17/2022]
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Mora F, Segovia G, Del Arco A, de Blas M, Garrido P. Stress, neurotransmitters, corticosterone and body-brain integration. Brain Res 2012; 1476:71-85. [PMID: 22285436 DOI: 10.1016/j.brainres.2011.12.049] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 12/26/2022]
Abstract
Stress can be defined as a brain-body reaction towards stimuli arising from the environment or from internal cues that are interpreted as a disruption of homeostasis. The organization of the response to a stressful situation involves not only the activity of different types of neurotransmitter systems in several areas of the limbic system, but also the response of neurons in these areas to several other chemicals and hormones, chiefly glucocorticoids, released from peripheral organs and glands. Thus, stress is probably the process through which body-brain integration plays a major role. Here we review first the responses to an acute stress in terms of neurotransmitters such as dopamine, acetylcholine, glutamate and GABA in areas of the brain involved in the regulation of stress responses. These areas include the prefrontal cortex, amygdala, hippocampus and nucleus accumbens and the interaction among those areas. Then, we consider the role of glucocorticoids and review some recent data about the interaction of these steroids with several neurotransmitters in those same areas of the brain. Also the actions of other substances (neuromodulators) released from peripheral organs such as the pancreas, liver or gonads (insulin, IGF-1, estrogens) are reviewed. The role of an environmental enrichment on these same responses is also discussed. Finally a section is devoted to put into perspective all these environmental-brain-body-brain interactions during stress and their consequences on aging. It is concluded that the integrative perspective framed in this review is relevant for better understanding of how the organism responds to stressful challenges and how this can be modified through different environmental conditions during the process of aging. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Francisco Mora
- Department of Physiology, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
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28
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Bakos J, Hlavacova N, Rajman M, Ondicova K, Koros C, Kitraki E, Steinbusch H, Jezova D. Enriched environment influences hormonal status and hippocampal brain derived neurotrophic factor in a sex dependent manner. Neuroscience 2009; 164:788-97. [DOI: 10.1016/j.neuroscience.2009.08.054] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 08/20/2009] [Accepted: 08/22/2009] [Indexed: 11/27/2022]
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Calisi RM, Bentley GE. Lab and field experiments: are they the same animal? Horm Behav 2009; 56:1-10. [PMID: 19281813 DOI: 10.1016/j.yhbeh.2009.02.010] [Citation(s) in RCA: 266] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 02/25/2009] [Accepted: 02/26/2009] [Indexed: 11/20/2022]
Abstract
To advance our understanding of biological processes we often plan our experiments based on published data. This can be confusing though, as data from experiments performed in a laboratory environment are sometimes different from, or completely opposite to, findings from similar experiments performed in the "real world". In this mini-review, we discuss instances where results from laboratory experiments differ as a result of laboratory housing conditions, and where they differ from results gathered in the field environment. Experiments involving endocrinology and behavior appear to be particularly susceptible to influence from the environment in which they are performed. As such, we have attempted to promote discussion of the influence of housing environment on the reproductive axis, circadian biology and behavior, immune function, stress biology, neuroplasticity and photoperiodism. For example, why should a rodent species be diurnal in one housing environment yet nocturnal in another? Are data that are gathered from experiments in the laboratory applicable to the field environment, and vice-versa? We hope not only to highlight the need for experiments in both lab and field when looking at complex biological systems, but also to promote frank discussion of discordant data. Perhaps, just as study of individual variation has been gaining momentum in recent years, data from variation between experimental arenas can provide us with novel lines of research.
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Affiliation(s)
- Rebecca M Calisi
- Laboratory of Reproductive Neuroendocrinology, Department of Integrative Biology and Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA 94720-3140, USA.
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Environmental enrichment, prefrontal cortex, stress, and aging of the brain. J Neural Transm (Vienna) 2009; 116:1007-16. [DOI: 10.1007/s00702-009-0214-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 03/17/2009] [Indexed: 12/17/2022]
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31
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Szabadfi K, Atlasz T, Horváth G, Kiss P, Hamza L, Farkas J, Tamás A, Lubics A, Gábriel R, Reglődi D. Early postnatal enriched environment decreases retinal degeneration induced by monosodium glutamate treatment in rats. Brain Res 2009; 1259:107-12. [DOI: 10.1016/j.brainres.2009.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 01/02/2009] [Accepted: 01/05/2009] [Indexed: 10/21/2022]
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Workman JL, Bowers SL, Nelson RJ. Enrichment and photoperiod interact to affect spatial learning and hippocampal dendritic morphology in white-footed mice (Peromyscus leucopus). Eur J Neurosci 2009; 29:161-70. [PMID: 19120443 DOI: 10.1111/j.1460-9568.2008.06570.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In seasonally changing environments, individuals must coordinate endogenous processes with ambient conditions. Winter is a challenging time to survive and reproduce. In order to anticipate decreased food availability and low temperatures in winter, many rodents use decreasing day lengths as a precise temporal cue. Short day lengths alter several adaptations, including reproduction, immune function, aggressive behavior and spatial learning in non-tropical rodents. Specifically, short days impair spatial learning in white-footed mice (Peromyscus leucopus) and alter dendritic complexity in the hippocampus. The goal of the current study was to determine whether short days constrain neural plasticity. If short days limit the capacity for plasticity, then environmental enrichment, a manipulation that induces morphological changes, should alter dendritic morphology in long, but not short, days. Male white-footed mice were assigned to long (16 : 8 LD) or short (8 : 16 LD) photoperiod in either enriched or standard cages. Enrichment consisted of a large cage, cage mates, Habitrail tubes, a nest box and a running wheel. Mice were tested in the Morris water maze. Reproductive tissues were collected and weighed; brains were processed for dendritic morphology. Short days impaired spatial learning. Short days also reduced spine density on apical dendrites within the CA3 region of the hippocampus. However, enrichment prevented short-day-induced deficits in learning and also increased hippocampal spine density in the CA1 and CA3 regions in short-day mice. These results suggest that day length and other non-photic environmental factors interact to regulate dendritic morphology, and that short photoperiods do not constrain the capacity for functional neural plasticity.
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Affiliation(s)
- Joanna L Workman
- Department of Psychology, The Ohio State University, Columbus, OH 43210, USA.
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33
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Dhanushkodi A, Shetty AK. Is exposure to enriched environment beneficial for functional post-lesional recovery in temporal lobe epilepsy? Neurosci Biobehav Rev 2007; 32:657-74. [PMID: 18178250 DOI: 10.1016/j.neubiorev.2007.10.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 09/24/2007] [Accepted: 10/29/2007] [Indexed: 01/19/2023]
Abstract
Exposure to enriched environment has been shown to induce robust neuronal plasticity in both intact and injured adult central nervous system, including up-regulation of multiple neurotrophic factors, enhanced neurogenesis in the dentate gyrus of the hippocampus, and improved spatial learning and memory function. Neuronal plasticity, though mostly adaptive and abnormal, also occurs during certain neurodegenerative conditions such as the temporal lobe epilepsy (TLE). The TLE is characterized by hippocampal neurodegeneration, aberrant mossy fiber sprouting, spontaneous recurrent motor seizures, cognitive deficits, and abnormally enhanced neurogenesis during the early phase and dramatically declined neurogenesis during the chronic phase of the disease. As environmental enrichment has been found to be beneficial for treating animal models of Alzheimer's, Parkinson's, and Huntington's diseases, there is considerable interest in determining the efficacy of this strategy for preventing or treating chronic TLE after the initial precipitating brain injury. This review first discusses the proof of principle behind the potential application of the environmental enrichment strategy for preventing or treating TLE after brain injury. The subsequent chapters confer the portrayed beneficial effects of enrichment for functional post-lesional recovery in TLE and the possible complications which may arise from housing epilepsy-prone or epileptic rats in enriched environmental conditions. The final segment discusses studies that are essential for further understanding the efficacy of this approach for preventing or treating TLE.
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Affiliation(s)
- Anandh Dhanushkodi
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705, USA
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Mora F, Segovia G, Del Arco A. Glutamate-dopamine-GABA interactions in the aging basal ganglia. ACTA ACUST UNITED AC 2007; 58:340-53. [PMID: 18036669 DOI: 10.1016/j.brainresrev.2007.10.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 10/05/2007] [Accepted: 10/06/2007] [Indexed: 12/25/2022]
Abstract
The study of neurotransmitter interactions gives a better understanding of the physiology of specific circuits in the brain. In this review we focus mostly on our own results on the interaction of the neurotransmitters glutamate, dopamine and GABA in the basal ganglia during the normal process of aging. We review first the studies on the action of endogenous glutamate on the extracellular concentrations of dopamine and GABA in the neostriatum and nucleus accumbens during aging. It was found that there exists an age-related change in the interaction of glutamate, dopamine and GABA and that these effects of aging exhibit a dorsal-to-ventral pattern of effects with no changes in the dorsal parts (dorsal striatum) and changes in the most ventral parts (nucleus accumbens). Second we reviewed the data on the effects of different ionotropic and metabotropic glutamate receptor agonists on the extracellular concentrations of dopamine and GABA in the nucleus accumbens. The results obtained clearly show the different contribution of each glutamate receptor subtype in the age-related changes produced on the interaction of glutamate, dopamine and GABA in this area of the brain. Third the effects of an enriched environment on the action of AMPA and NMDA-receptor agonists in the nucleus accumbens of rats during aging are also evaluated. Finally, and since the nucleus accumbens has been suggested to play a role in emotion and motivation and also motor behaviour, we speculated on the possibility of a specific contribution for the different glutamatergic pathways terminating in the nucleus accumbens and their interaction with a decreased dopamine playing a relevant role in motor behaviour during aging.
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Affiliation(s)
- Francisco Mora
- Department of Physiology, Faculty of Medicine, Universidad Complutense, Ciudad Universitaria, s/n 28040 Madrid, Spain.
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35
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Andin J, Hallbeck M, Mohammed AH, Marcusson J. Influence of environmental enrichment on steady-state mRNA levels for EAAC1, AMPA1 and NMDA2A receptor subunits in rat hippocampus. Brain Res 2007; 1174:18-27. [PMID: 17854777 DOI: 10.1016/j.brainres.2007.06.101] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Revised: 06/18/2007] [Accepted: 06/23/2007] [Indexed: 11/24/2022]
Abstract
Interaction with the environment has a key role in refining the neuronal circuitry required for normal brain function throughout life. Profound effects of enriched environment have been shown on neuronal structure and chemistry in experimental animals. Epidemiological studies imply that this is true also in man, thus cognitive stimulation has a protective effect on neurodegeneration, e.g., in Alzheimer's disease. Glutamatergic pathways are imperative for cognitive functions, such as memory, learning and long-term potentiation, and relies on the AMPA and NMDA glutamate receptors and the hippocampus, with its specific subregions, is an important anatomical substrate in this. The glutamate signalling is also dependent on a fine-tuned transport system, in the hippocampus primarily achieved by the glutamate transporter EAAC1. In this study we show how environmental enrichment modulates these parts of the glutamatergic system using quantitative in situ hybridisation. This work demonstrates for the first time that environmental enrichment modulates the mRNA expression of EAAC1 which is significantly and region specifically decreased in the hippocampus. We also provide evidence for regional and hemisphere-specific upregulation of NMDA mRNA in the hippocampus after environmental enrichment. The current work also shows that AMPA mRNA of the hippocampus is not per se changed by environmental enrichment in adult animals. Taken together, our results extend the knowledge of the glutamatergic system of specific regions of the hippocampus and its modulation by environmental enrichment and could contribute to the development of strategies aimed at limiting pathological changes associated with glutamatergic dysfunctions.
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Affiliation(s)
- Josefine Andin
- Department of Neuroscience and Locomotion, Division of Geriatric Medicine, Linköpings Universitet, SE-581 85 Linköping, Sweden.
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36
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Lupien SJ, Maheu F, Tu M, Fiocco A, Schramek TE. The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition. Brain Cogn 2007; 65:209-37. [PMID: 17466428 DOI: 10.1016/j.bandc.2007.02.007] [Citation(s) in RCA: 806] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 02/04/2007] [Accepted: 02/21/2007] [Indexed: 11/20/2022]
Abstract
In this review, we report on studies that have assessed the effects of exogenous and endogenous increases in stress hormones on human cognitive performance. We first describe the history of the studies on the effects of using exogenous stress hormones such as glucocorticoids as anti-inflammatory medications on human cognition and mental health. Here, we summarize the cases that led to the diagnosis of glucocorticoid-induced 'steroid psychosis' in human populations and which demonstrated that these stress hormones could thus cross the blood-brain barrier and access the brain where they could influence cognition and mental health. We then summarize studies that assessed the effects of the exogenous administration of glucocorticoids on cognitive performance supported by the hippocampus, the frontal lobes and amygdala. In the second section of the paper, we summarize the effects of the endogenous release of glucocorticoids induced by exposure to a stressful situation on human cognition and we further dissociate the effects of emotion from those of stress on human learning and memory. Finally, in the last section of the paper, we discuss the potential impact that the environmental context to which we expose participants when assessing their memory could have on their reactivity to stress and subsequent cognitive performance. In order to make our point, we discuss the field of memory and aging and we suggest that some of the 'age-related memory impairments' observed in the literature could be partly due to increased stress reactivity in older adults to the environmental context of testing. We also discuss the inverse negative correlations reported between hippocampal volume and memory for young and older adults and suggest that these inverse correlations could be partly due to the effects of contextual stress in young and older adults, as a function of age-related differences in hippocampal volume.
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Affiliation(s)
- S J Lupien
- Center for Studies on Human Stress, Douglas Hospital Research Center, McGill University, Montreal, QC, Canada.
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37
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Mora F, Segovia G, del Arco A. Aging, plasticity and environmental enrichment: structural changes and neurotransmitter dynamics in several areas of the brain. ACTA ACUST UNITED AC 2007; 55:78-88. [PMID: 17561265 DOI: 10.1016/j.brainresrev.2007.03.011] [Citation(s) in RCA: 281] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 03/19/2007] [Accepted: 03/19/2007] [Indexed: 12/11/2022]
Abstract
Cajal was probably the first neurobiologist to suggest that plasticity of nerve cells almost completely disappeared during aging. However, we know today that neural plasticity is still present in the brain during aging. In this review we suggest that aging is a physiological process that occurs asynchronously in different areas of the brain and that the rate of that process is modulated by environmental factors and related to the neuronal-synaptic-molecular substrates of each area. We review here some of the most recent results on aging of the brain in relation to the plastic changes that occur in young and aged animals as a result of living in an enriched environment. We highlight the results from our own laboratory on the dynamics of neurotransmitters in different areas of the brain. Specifically we review first the effects of aging on neurons, dendrites, synapses, and also on molecular and functional plasticity. Second, the effects of environmental enrichment on the brain of young and aged animals. And third the effects of an enriched environment on the age-related changes in neurogenesis and in the extracellular concentrations of glutamate and GABA in hippocampus, and on dopamine, acetylcholine, glutamate and GABA under a situation of acute mild stress in the prefrontal cortex.
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Affiliation(s)
- Francisco Mora
- Department of Physiology, Faculty of Medicine, Universidad Complutense, Ciudad Universitaria, s/n, 28040 Madrid, Spain.
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38
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Magalon K, Cantarella C, Monti G, Cayre M, Durbec P. Enriched environment promotes adult neural progenitor cell mobilization in mouse demyelination models. Eur J Neurosci 2007; 25:761-71. [PMID: 17298600 DOI: 10.1111/j.1460-9568.2007.05335.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Since the discovery of adult neural stem cells, mobilization of endogenous stem cells from the subventricular zone (SVZ) emerges as a promising strategy to promote brain repair. Here, we examined the effect of environment enrichment on SVZ cell mobilization in demyelinating pathologies. We showed that enriched housing conditions reduced functional impairment in experimental autoimmune encephalomyelitis (EAE), a rodent model of multiple sclerosis. Furthermore, both in a focal demyelination model (lysolecithin injection) and in the inflammatory EAE model, SVZ mitotic activity and the number of SVZ-derived cells in demyelinated areas were significantly increased by environment enrichment. Enriched housing conditions also promoted the oligodendrocyte fate of SVZ-recruited cells in the EAE lesions. Altogether our results show that environment enrichment provides beneficial conditions to promote the mobilization of neural progenitors into demyelinating lesions and to favour functional recovery.
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Affiliation(s)
- Karine Magalon
- Institut de Biologie du developpement de Marseille Luminy, Parc Scientifique de Luminy, Marseille, France
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39
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Lupien SJ, Evans A, Lord C, Miles J, Pruessner M, Pike B, Pruessner JC. Hippocampal volume is as variable in young as in older adults: implications for the notion of hippocampal atrophy in humans. Neuroimage 2006; 34:479-85. [PMID: 17123834 DOI: 10.1016/j.neuroimage.2006.09.041] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 09/28/2006] [Accepted: 09/29/2006] [Indexed: 02/02/2023] Open
Abstract
Previous studies in humans have shown the presence of an age-related reduction of hippocampal (HC) volume, as well as the presence of reduced HC volume in psychiatric populations suffering from schizophrenia, depression or post-traumatic stress disorder. Altogether, these data suggested that aging or psychiatric disease can have neurotoxic effects on the hippocampus, and lead to HC atrophy. However, these two sets of findings imply that HC volume in young healthy adults should present less variability than HC volume in older adults and psychiatric populations. In the present study, we assessed HC volume in 177 healthy men and women aged from 18 to 85 years of age. We show that the dispersion around the mean of HC volume is not different in young and older adults, so that 25% of young healthy adults present HC volume as small as the average participants aged 60 to 75 years. This shows that HC volume is as variable in young as in older adults and suggests that smaller HC volume attributed to the aging process in previous studies could in fact represent HC volume determined early in life. We also report that within similar age groups, the percentage of difference in HC volume between the individuals with the smallest HC volume (smallest quartile) and the group average is greater than the percentage of difference reported to exist between psychiatric populations and normal control in recent meta-analyses. Taken together, these results confront the notion of hippocampal atrophy in humans and raise the possibility that pre-determined inter-individual differences in HC volume in humans may determine the vulnerability for age-related cognitive impairments or psychopathology throughout the lifetime.
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Affiliation(s)
- S J Lupien
- Center for Studies on Human Stress, Douglas Hospital Research Center, McGill University, 6875 Blvd. LaSalle, Montreal, Quebec, Canada H4H 1R3.
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40
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Woo CC, Hingco EE, Johnson BA, Leon M. Broad activation of the glomerular layer enhances subsequent olfactory responses. Chem Senses 2006; 32:51-5. [PMID: 17071941 PMCID: PMC2213453 DOI: 10.1093/chemse/bjl035] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Early olfactory experience with a specific odorant enhances the subsequent response of the glomerular layer of the rat olfactory bulb to that same odorant. Because different odorants activate different glomerular layer regions, it seemed plausible that experience with a large number of odorants might result in enhanced glomerular activation during subsequent exposure to both the previously experienced odorants and the novel odorants evoking activity in regions that overlapped with those previously stimulated by different odorants. To this end, 7 odorants were selected using our glomerular response data archive that together stimulated much of the glomerular layer (alpha-phellandrene, benzaldehyde, L-carvone, decanal, pentanol, santalol, and valeric acid). Young rats were exposed to a different odorant each day for 7 days, and this cycle was repeated 3 times from postnatal days 1-21. The [(14)C]2-deoxyglucose technique was used to measure neural activity in response to both previously experienced and novel odorants. The 2 novel odorants (alpha-ionone and L-menthone) activate regions of the glomerular layer that overlap with those stimulated by the 7 enrichment odorants. Our results indicate that early experience with multiple odorants results in increased responsiveness both to previously experienced odorants and to novel odorants that stimulate previously activated regions of the bulb.
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Affiliation(s)
- Cynthia C Woo
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-4550, USA.
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41
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Pickering C, Gustafsson L, Cebere A, Nylander I, Liljequist S. Repeated maternal separation of male Wistar rats alters glutamate receptor expression in the hippocampus but not the prefrontal cortex. Brain Res 2006; 1099:101-8. [PMID: 16784730 DOI: 10.1016/j.brainres.2006.04.136] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 04/19/2006] [Accepted: 04/20/2006] [Indexed: 11/20/2022]
Abstract
Stress early in life puts the individual at a greater risk for developing mental disorders in adulthood. The animal model of maternal separation involves daily removal of pups from their mother over the early postnatal period and leads to several behavioral deficits in adults. Since this period corresponds to a time of extensive developmental changes in the glutamatergic system, glutamate receptor mRNA expression was studied in the hippocampus and prefrontal cortex. Male Wistar rats were either separated from their mother for 15 min (MS15 or 'handling') or 360 min (MS360) once a day from pnd 1-21 and glutamate receptor expression levels were measured at 25 weeks of age using real-time RT-PCR analysis. A third group of animal facility reared (AFR) rats was included as a control for the handling group. In the hippocampus, mRNA expression of NMDA NR2B and AMPA GluR1 and GluR2 receptors was significantly lower in MS360 rats relative to MS15. In addition, expression of the glutamate transporter GLAST was increased in MS360 relative to MS15. No differences were observed for AFR rats relative to MS15, which indicates that the hippocampal effects were not a result of handling or maternal care. For the prefrontal cortex, no difference in mRNA expression was observed for NMDA NR2A and NR2B or AMPA GluR1 and GluR2. These findings suggest that prolonged maternal separation produces neuroadaptive changes in the hippocampus that may, at least partially, account for the behavioral deficits previously observed in this animal model.
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Affiliation(s)
- Chris Pickering
- Department of Clinical Neuroscience, Division of Drug Dependence Research, Karolinska Institutet, Stockholm, Sweden.
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42
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Restivo L, Ferrari F, Passino E, Sgobio C, Bock J, Oostra BA, Bagni C, Ammassari-Teule M. Enriched environment promotes behavioral and morphological recovery in a mouse model for the fragile X syndrome. Proc Natl Acad Sci U S A 2005; 102:11557-62. [PMID: 16076950 PMCID: PMC1183589 DOI: 10.1073/pnas.0504984102] [Citation(s) in RCA: 221] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Indexed: 02/08/2023] Open
Abstract
Fragile X syndrome, the most frequent form of hereditary mental retardation, is due to a mutation of the fragile X mental retardation 1 (FMR1) gene on the X chromosome. Like fragile X patients, FMR1-knockout (FMR1-KO) mice lack the normal fragile X mental retardation protein (FMRP) and show both cognitive alterations and an immature neuronal morphology. We reared FMR1-KO mice in a C57BL/6 background in enriched environmental conditions to examine the possibility that experience-dependent stimulation alleviates their behavioral and neuronal abnormalities. FMR1-KO mice kept in standard cages were hyperactive, displayed an altered pattern of open field exploration, and did not show habituation. Quantitative morphological analyses revealed a reduction in basal dendrite length and branching together with more immature-appearing spines along apical dendrites of layer five pyramidal neurons in the visual cortex. Enrichment largely rescued these behavioral and neuronal abnormalities while increasing alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subunit 1 (GluR1) levels in both genotypes. Enrichment did not, however, affect FMRP levels in the WT mice. These data suggest that FMRP-independent pathways activating glutamatergic signaling are preserved in FMR1-KO mice and that they can be elicited by environmental stimulation.
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Affiliation(s)
- Leonardo Restivo
- Laboratory of Psychobiology, Consiglio Nazionale delle Ricerche Institute of Neuroscience, 00179 Rome, Italy
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Nickerson M, Elphick GF, Campisi J, Greenwood BN, Fleshner M. Physical activity alters the brain Hsp72 and IL-1beta responses to peripheral E. coli challenge. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1665-74. [PMID: 16081876 DOI: 10.1152/ajpregu.00601.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Physically active rats have facilitated heat shock protein 72 (Hsp72) responses after stressor exposure in both brain and peripheral tissues compared with sedentary rats. This study verifies that physically active animals do not have elevated Hsp72 levels compared with sedentary animals in the hypothalamus, pituitary, or dorsal vagal complex. We then examined whether 1) physically active rats respond more efficiently than sedentary rats to a bacterial challenge; 2) peripheral immune challenge elicits brain induction of Hsp72; 3) this induction is facilitated by prior freewheel running; and 4) Hsp72 upregulation produced by peripheral immune challenge results in a commensurate decrease in the proinflammatory cytokine IL-1beta. Adult male Fischer 344 rats were housed with either a mobile or locked running wheel. Six weeks later, rats were injected intraperitoneally with saline or Escherichia coli and killed 30 min, 2.5 h, 6 h, and 24 h later. Serum endotoxin and IL-1beta, and peritoneal fluid endotoxin and E. coli colony-forming units (CFUs) were measured. Hsp72 and IL-1beta were measured in hypothalamus, pituitary, and dorsal vagal complex. The results were that physically active rats had a faster reduction in endotoxin and E. coli CFUs and lower levels of circulating endotoxin and cytokines compared with sedentary rats. E. coli challenge elicited significantly greater time-dependent increases of both Hsp72 and IL-1beta in hypothalamus, pituitary, and dorsal vagal complex of physically active animals but not sedentary animals. Contrary to our hypothesis, increases in Hsp72 were positively correlated with IL-1beta. This study extends our findings that physical activity facilitates stress-induced Hsp72 to include immunological stressors such as bacterial challenge and suggests that brain Hsp72 and IL-1beta responses to peripheral immune challenge may contribute to exercise-mediated resistance to long-term sickness.
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Affiliation(s)
- M Nickerson
- Dept. of Integrative Physiology, Neuroimmunophysiology Laboratory, Univ. of Colorado, Boulder, CO 80309, USA
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