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Borland JM. The effects of different types of social interactions on the electrophysiology of neurons in the nucleus accumbens in rodents. Neurosci Biobehav Rev 2024; 164:105809. [PMID: 39004323 DOI: 10.1016/j.neubiorev.2024.105809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/16/2024]
Abstract
BORLAND, J.M., The effects of different types of social interactions on the electrophysiology of neurons in the nucleus accumbens in rodents, NEUROSCI BIOBEH REV 21(1) XXX-XXX, 2024.-Sociality shapes an organisms' life. The nucleus accumbens is a critical brain region for mental health. In the following review, the effects of different types of social interactions on the physiology of neurons in the nucleus accumbens is synthesized. More specifically, the effects of sex behavior, aggression, social defeat, pair-bonding, play behavior, affiliative interactions, parental behaviors, the isolation from social interactions and maternal separation on measures of excitatory synaptic transmission, intracellular signaling and factors of transcription and translation in neurons in the nucleus accumbens in rodent models are reviewed. Similarities and differences in effects depending on the type of social interaction is then discussed. This review improves the understanding of the molecular and synaptic mechanisms of sociality.
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Mao LM, Mathur N, Wang JQ. Downregulation of surface AMPA receptor expression in the striatum following prolonged social isolation, a role of mGlu5 receptors. IBRO Neurosci Rep 2022; 13:22-30. [PMID: 35711245 PMCID: PMC9193854 DOI: 10.1016/j.ibneur.2022.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/16/2022] [Accepted: 05/28/2022] [Indexed: 11/10/2022] Open
Abstract
Major depressive disorder is a common and serious mood illness. The molecular mechanisms underlying the pathogenesis and symptomatology of depression are poorly understood at present. Multiple neurotransmitter systems are believed to be implicated in depression. Increasing evidence supports glutamatergic transmission as a critical element in depression and antidepressant activity. In this study, we investigated adaptive changes in expression of AMPA receptors in a key limbic reward structure, the striatum, in response to an anhedonic model of depression. Prolonged social isolation in adult rats caused anhedonic/depression- and anxiety-like behavior. In these depressed rats, surface levels of AMPA receptors, mainly GluA1 and GluA3 subunits, were reduced in the nucleus accumbens (NAc). Surface GluA1/A3 expression was also reduced in the caudate putamen (CPu) following chronic social isolation. No change was observed in expression of presynaptic synaptophysin, postsynaptic density-95, and dendritic microtubule-associated protein 2 in the striatum. Noticeably, chronic treatment with the metabotropic glutamate (mGlu) receptor 5 antagonist MTEP reversed the reduction of AMPA receptors in the NAc and CPu. MTEP also prevented depression- and anxiety-like behavior induced by social isolation. These data indicate that adulthood prolonged social isolation induces the adaptive downregulation of GluA1/A3-containing AMPA receptor expression in the limbic striatum. mGlu5 receptor activity is linked to this downregulation, and antagonism of mGlu5 receptors produces an antidepressant effect in this anhedonic model of depression.
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Key Words
- AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid;
- ANOVA, analysis of variance
- Antidepressant
- CDH2, Cadherin-2
- CPu, caudate putamen
- Caudate putamen
- GluA1
- MAP-2, microtubule-associated protein 2
- MTEP
- MTEP, 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine
- Metabotropic glutamate receptor
- NAc, nucleus accumbens
- NCAD, neural cadherin
- Nucleus accumbens
- PFC, prefrontal cortex
- PSD-95, postsynaptic density-95
- Social isolation
- mGlu, metabotropic glutamate
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Affiliation(s)
- Li-Min Mao
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Nirav Mathur
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - John Q. Wang
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA,Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA,Correspondence to: Department of Biomedical Sciences, University of Missouri-Kansas City, School of Medicine, 2411 Holmes Street, Kansas City, MO 64108, USA.
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Novoa J, Rivero CJ, Pérez-Cardona EU, Freire-Arvelo JA, Zegers J, Yarur HE, Santiago-Marerro IG, Agosto-Rivera JL, González-Pérez JL, Gysling K, Segarra AC. Social isolation of adolescent male rats increases anxiety and K + -induced dopamine release in the nucleus accumbens: Role of CRF-R1. Eur J Neurosci 2021; 54:4888-4905. [PMID: 34097788 DOI: 10.1111/ejn.15345] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/08/2021] [Accepted: 05/04/2021] [Indexed: 12/19/2022]
Abstract
Early life adversity can disrupt development leading to emotional and cognitive disorders. This study investigated the effects of social isolation after weaning on anxiety, body weight and locomotion, and on extracellular dopamine (DA) and glutamate (GLU) in the nucleus accumbens (NAc) and their modulation by corticotropin releasing factor receptor 1. On the day of weaning, male rats were housed singly or in groups for 10 consecutive days. Anxiety-like behaviors were assessed by an elevated plus maze (EPM) and an open field test (OF). Neurotransmitter levels were measured by in vivo microdialysis. Single-housed rats spent less time, and entered more, into the closed arms of an EPM than group-housed rats. They also spent less time in the center of an OF, weighed more and showed greater locomotion. In the NAc, no differences in CRF, or in basal extracellular DA or GLU between groups, were observed. A depolarizing stimulus increased DA release in both groups but to higher levels in isolated rats, whereas GLU increased only in single-housed rats. Blocking CRF-R1 receptors with CP-154,526 decreased DA release in single-housed but not in group-housed rats. The corticotropin releasing factor receptor type 1 receptor antagonist also decreased GLU in group-housed animals. These results show that isolating adolescent rats increases anxiety, body weight and ambulation, as well as the sensitivity of dopaminergic neurons to a depolarizing stimulus. This study provides further evidence of the detrimental effects of social isolation during early development and indicates that dysregulation of the CRF system in the NAc may contribute to the pathologies observed.
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Affiliation(s)
- Javier Novoa
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos J Rivero
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Enrique U Pérez-Cardona
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Jaime A Freire-Arvelo
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Juan Zegers
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Héctor E Yarur
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | | | | - Jorge L González-Pérez
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
| | - Katia Gysling
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Annabell C Segarra
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
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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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Bonfiglio T, Vergassola M, Olivero G, Pittaluga A. Environmental Training and Synaptic Functions in Young and Old Brain: A Presynaptic Perspective. Curr Med Chem 2019; 26:3670-3684. [PMID: 29493441 DOI: 10.2174/0929867325666180228170450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/14/2018] [Accepted: 02/15/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Aging is an unavoidable, physiological process that reduces the complexity and the plasticity of the synaptic contacts in Central Nervous System (CNS), having profound implications for human well-being. The term "cognitive reserve" refers to central cellular adaptations that augment the resilience of human brain to damage and aging. The term "Cognitive training" indicates the cultural, social and physical stimulations proposed as add-on therapy for the cure of central neurological diseases. "Cognitive training" reinforces the "cognitive reserve" permitting to counteract brain impairments and rejuvenating synaptic complexity. The research has begun investigating the clinical impact of the "cognitive training" in aged people, but additional work is needed to definitively assess its effectiveness. In particular, there is a need to understand, from a preclinical point of view, whether "cognitive training" promotes compensatory effects or, alternatively, if it elicits genuine recovery of neuronal defects. Although the translation from rodent studies to the clinical situation could be difficult, the results from pre-clinical models are of high clinical relevance, since they should allow a better understanding of the effects of environmental interventions in aging-associated chronic derangements in mammals. CONCLUSION Data in literature and the recent results obtained in our laboratory concerning the impact of environmental stimulation on the presynaptic release of noradrenaline, glutamate and gamma amino butyric acid (GABA) suggest that these neurotransmitters undergo different adaptations during aging and that they are differently tuned by "cognitive training". The impact of "cognitive training" on neurotransmitter exocytosis might account for the cellular events involved in reinforcement of "cognitive reserve" in young and old animals.
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Affiliation(s)
- Tommaso Bonfiglio
- Department of Pharmacy, DIFAR, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy
| | - Matteo Vergassola
- Department of Pharmacy, DIFAR, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy
| | - Guendalina Olivero
- Department of Pharmacy, DIFAR, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy
| | - Anna Pittaluga
- Department of Pharmacy, DIFAR, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy.,Center of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 16132 Genoa, Italy
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Fitzgerald ML, Pickel VM. Adolescent isolation rearing produces a prepulse inhibition deficit correlated with expression of the NMDA GluN1 subunit in the nucleus accumbens. Brain Struct Funct 2018; 223:3169-3181. [PMID: 29779156 PMCID: PMC6626533 DOI: 10.1007/s00429-018-1673-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 04/27/2018] [Indexed: 12/18/2022]
Abstract
Adolescence is a transition period during which social interaction is necessary for normal brain and behavior development. Severely abnormal social interactions during adolescence can increase the incidence of lifelong psychiatric disease. Decreased prepulse inhibition (PPI) is a quantifiable hallmark of some psychiatric illnesses in humans and can be elicited in rodents by isolation rearing throughout the adolescent transition period. PPI is a measure of sensorimotor gating in which the nucleus accumbens (Acb) is crucially involved. The Acb is comprised of core and shell subregions, which receive convergent dopaminergic and glutamatergic inputs. To gain insight into the neurobiological correlates of adolescent adversity, we conducted electron microscopic immunolabeling of dopamine D1 receptors (D1Rs) and the GluN1 subunit of glutamate NMDA receptors in the Acb of isolation-reared (IR) adult male rats. In all animals, GluN1 was primarily located in dendritic profiles, many of which also contained D1Rs. GluN1 was also observed in perisynaptic glia and axon terminals. In IR rats compared with group-reared controls, GluN1 density was selectively decreased in D1R-containing dendrites of the Acb core. Across all animals, dendritic GluN1 density correlated with average percent PPI, implicating endogenous expression of NMDA receptors of the Acb as a possible substrate of the PPI response. These results suggest that adolescent isolation dampens NMDA-mediated excitation in direct (D1R-containing) output neurons of the Acb, and that these changes influence the operational measure of PPI.
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Affiliation(s)
- Megan L Fitzgerald
- Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA
- New York State Psychiatric Institute, Columbia University, New York, NY, 10032, USA
| | - Virginia M Pickel
- Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA.
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Grigsby KB, Kovarik CM, Rottinghaus GE, Booth FW. High and low nightly running behavior associates with nucleus accumbens N-Methyl-d-aspartate receptor (NMDAR) NR1 subunit expression and NMDAR functional differences. Neurosci Lett 2018; 671:50-55. [PMID: 29425730 DOI: 10.1016/j.neulet.2018.02.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 11/19/2022]
Abstract
The extent to which N-Methyl-d-aspartate (NMDA) receptors facilitate the motivation to voluntarily wheel-run in rodents has yet to be determined. In so, we utilized female Wistar rats selectively bred to voluntarily run high (HVR) and low (LVR) nightly distances in order to examine if endogenous differences in nucleus accumbens (NAc) NMDA receptor expression and function underlies the propensity for high or low motivation to voluntarily wheel-run. 12-14 week old HVR and LVR females were used to examine: 1.) NAc mRNA and protein expression of NMDA subunits NR1, NR2A and NR2B; 2.) NMDA current responses in isolated medium spiny neurons (MSNs) and 3.) NMDA-evoked dopamine release in an ex vivo preparation of NAc punches. Expectedly, there was a large divergence in nightly running distance and time between HVR and LVR rats. We saw a significantly higher mRNA and protein expression of NR1 in HVR compared to LVR rats, while seeing no difference in the expression of NR2A or NR2B. There was a greater current response to a 500 ms application of 300 μM of NMDA in medium-spiny neurons isolated from the NAc HVR compared to LVR animals. On average, NMDA-evoked punches (50 μM of NMDA for 10 min) taken from HVR rats retained ∼54% of the dopamine content compared to their bilateral non-evoked sides, while evoked punches from LVR animals showed no statistical decrease in dopamine content compared to their non-evoked sides. Collectively, these data suggest a potential link between NAc NR1 subunit expression as well as NMDA function and the predisposition for nightly voluntary running behavior in rats. In light of the epidemic rise in physical inactivity, these findings have the potential to explain a neuro-molecular mechanism that regulates the motivation to be physically active.
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Affiliation(s)
- Kolter B Grigsby
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States.
| | - Cathleen M Kovarik
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States
| | - George E Rottinghaus
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, United States; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, United States; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States; Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
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8
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Piña JA, Namba MD, Leyrer-Jackson JM, Cabrera-Brown G, Gipson CD. Social Influences on Nicotine-Related Behaviors. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 140:1-32. [DOI: 10.1016/bs.irn.2018.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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9
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Zachar G, Tóth AS, Balogh M, Csillag A. Effect of nucleus accumbens lesions on socially motivated behaviour of young domestic chicks. Eur J Neurosci 2016; 45:1606-1612. [DOI: 10.1111/ejn.13402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 08/26/2016] [Accepted: 09/13/2016] [Indexed: 12/01/2022]
Affiliation(s)
- Gergely Zachar
- Department of Anatomy; Histology and Embryology; Semmelweis University; 58 Tűzoltó u Budapest 1094 Hungary
| | - András Sebestyén Tóth
- Department of Anatomy; Histology and Embryology; Semmelweis University; 58 Tűzoltó u Budapest 1094 Hungary
| | - Márton Balogh
- Department of Anatomy; Histology and Embryology; Semmelweis University; 58 Tűzoltó u Budapest 1094 Hungary
| | - András Csillag
- Department of Anatomy; Histology and Embryology; Semmelweis University; 58 Tűzoltó u Budapest 1094 Hungary
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Kirkpatrick K, Marshall AT, Clarke J, Cain ME. Environmental rearing effects on impulsivity and reward sensitivity. Behav Neurosci 2014; 127:712-24. [PMID: 24128360 DOI: 10.1037/a0034124] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous research has indicated that rearing in an enriched environment may promote self-control in an impulsive choice task. To further assess the effects of rearing environment on impulsivity, 2 experiments examined locomotor activity, impulsive action, impulsive choice, and different aspects of reward sensitivity and discrimination. In Experiment 1, rats reared in isolated or enriched conditions were tested on an impulsive choice procedure with a smaller-sooner versus a larger-later reward, revealing that the isolated rats valued the smaller-sooner reward more than the enriched rats. A subsequent reward challenge was presented in which the delay to the 2 rewards was the same but the magnitude difference remained. The enriched rats did not choose the larger reward as often as the isolated rats, reflecting poorer reward discrimination. Impulsive action was assessed using a differential-reinforcement-of-low-rate task, which revealed deficits in the enriched rats. In Experiment 2, rats reared in isolated, standard, or enriched conditions were tested on reward contrast and reward magnitude sensitivity procedures. The rats were presented with 2 levers that delivered different magnitudes of food on variable interval 30-s schedules. Across all tests, the enriched and social rats displayed more generalized responding to the small-reward lever, but a similar response to the large-reward lever, compared with the isolated rats. This confirmed the results of Experiment 1, indicating poorer reward discrimination in the enriched condition compared with the isolated condition. The results suggest that enrichment may moderate reward generalization/discrimination processes through alterations in incentive motivational processes.
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Individual differences in impulsive and risky choice: effects of environmental rearing conditions. Behav Brain Res 2014; 269:115-27. [PMID: 24769268 DOI: 10.1016/j.bbr.2014.04.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/06/2014] [Accepted: 04/14/2014] [Indexed: 11/22/2022]
Abstract
The present experiment investigated early-rearing environment modulation of individual differences in impulsive and risky choice. Rats were reared in an isolated condition (IC; n=12), in which they lived alone without novel stimuli, or an enriched condition (EC; n=11), in which they lived among conspecifics with novel stimuli. The impulsive choice task involved choices between smaller-sooner (SS) versus larger-later (LL) rewards. The risky choice task involved choices between certain-smaller (C-S) versus uncertain-larger (U-L) rewards. Following choice testing, incentive motivation to work for food was measured using a progressive ratio task and correlated with choice behavior. HPLC analyses were conducted to determine how monoamine concentrations within the prefrontal cortex (PFC) and nucleus accumbens (NAC) related to behavior in different tasks. IC rats were more impulsive than EC rats, but they did not differ in risky choice behavior. However, choice behavior across tasks was significantly correlated (i.e., the more impulsive rats were also riskier). There were no group differences in monoamine levels, but noradrenergic and serotonergic concentrations were significantly correlated with impulsive and risky choice. Furthermore, serotonin and norepinephrine concentrations in the NAC significantly correlated with incentive motivation and the timing of the reward delays within the choice tasks. These results suggest a role for domain general processes in impulsive and risky choice and indicate the importance of the NAC and/or PFC in timing, reward processing, and choice behavior.
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Perez-Sepulveda JA, Flagel SB, Garcia-Fuster MJ, Slusky RJ, Aldridge JW, Watson S, Akil H. Differential impact of a complex environment on positive affect in an animal model of individual differences in emotionality. Neuroscience 2013; 248:436-47. [PMID: 23806722 DOI: 10.1016/j.neuroscience.2013.06.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 01/16/2023]
Abstract
Anhedonia, or the inability to experience positive feelings is a hallmark of depression. However, few animal models have relied on decreased positive affect as an index of susceptibility to depression. Rats emit frequency-modulated ultrasonic vocalizations (USVs), designated as "positive" calls in the 50-kHz range. USVs have been associated with pharmacological activation of motivational reward circuits. Here we utilized selectively-bred rats differing in "emotionality" to ask whether there are associated differences in USVs. Rats bred based on locomotor response to novelty and classified as bred High Responders (bHRs) or bred Low Responders (bLRs) exhibit inborn differences in response to environmental cues, stress responsiveness, and depression-like behavior. These animals also exhibit differences in anxiety-like behavior, which are reversed by exposure to environmental complexity (EC). Finally, these animals exhibit unique profiles of responsiveness to rewarding stimuli accompanied with distinct patterns of dopamine regulation. We investigated whether acute and chronic environmental manipulations impacted USVs in bHRs and bLRs. We found that, relative to bLRs, bHRs emitted significantly more 50-kHz USVs. However, if a bLR is accompanied by another bLR, there is a significant increase in 50-kHZ USVs emitted by this phenotype. bHRs emitted increases in 50-kHZ UVSs upon first exposure to EC, whereas bLRs showed a similar increase only after repeated exposure. bLRs' increase in positive affect after chronic EC was coupled with significant positive correlations between corticosterone levels and c-fos mRNA in the accumbens. Conversely, a decline in the rate of positive calls in bHRs after chronic EC was associated with a negative correlation between corticosterone and accumbens c-fos mRNA. These studies demonstrate that inborn differences in emotionality interact with the environment to influence positive affect and underscore the potential interaction between glucocorticoids and the mesolimbic reward circuitry in modulating 50-kHz calls.
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Affiliation(s)
- J A Perez-Sepulveda
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23219-1534, United States.
| | - S B Flagel
- Department of Psychiatry, University of Michigan, Ann Arbor, MI 48109, United States; Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States; Department of Psychology, University of Michigan, Ann Arbor, MI 48109, United States
| | - M J Garcia-Fuster
- University Research Institute on Health Sciences, University of the Balearic Islands, Palma de Mallorca, Spain
| | - R J Slusky
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - J W Aldridge
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, United States
| | - S Watson
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - H Akil
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
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Soares RO, Oliveira LM, Marchini JS, Antunes-Rodrigues J, Elias LLK, Almeida SS. Effects of early protein malnutrition and environmental stimulation on behavioral and biochemical parameters in rats submitted to the elevated plus-maze test. Nutr Neurosci 2012; 16:104-12. [PMID: 23321577 DOI: 10.1179/1476830512y.0000000036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The objective of this study was to compare the effects of the tactile/handling stimulation (H) and environmental enrichment (EE) in well-nourished (C - 16% of protein) and malnourished (M - 6% of protein) rats tested in the elevated plus-maze (EPM) at 36 and 37 days of age. The results showed higher exploration of the open arms in the EPM in M as compared with C animals, as well as lower index of risk assessment behaviors, and EE, but not H, reversed the alterations produced by malnutrition in the EPM. Biochemical analysis showed higher levels of corticosterone in M when compared with C rats. The non-stimulated animals presented higher levels of polyamines in the hippocampus when compared with the stimulated ones in both diet conditions. It is suggested that both the lower anxiety levels and the lower risk-assessment behaviors in the EPM, as well as the higher levels of corticosterone, can be due to alterations in the activity of the hypothalamic-pituitary-adrenal axis as the result of early protein malnutrition.
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Affiliation(s)
- Roberto O Soares
- Department of Psychology, FFCLRP, University of São Paulo, Brazil
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14
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Impact of mGluR5 during amphetamine-induced hyperactivity and conditioned hyperactivity in differentially reared rats. Psychopharmacology (Berl) 2012; 221:227-37. [PMID: 22139452 DOI: 10.1007/s00213-011-2565-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 10/28/2011] [Indexed: 12/23/2022]
Abstract
RATIONALE 3-((2-Methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP) is a metabotropic glutamate receptor 5 (mGluR5) antagonist that may alter drug sensitivity in differentially reared rats due to its involvement in the psychostimulant reward pathway and plasticity. OBJECTIVES The purpose of this study was to assess the effects of MTEP on acute amphetamine-induced hyperactivity, conditioned hyperactivity, and sensitization. METHODS Rats were reared in an enriched (EC), isolated (IC), or standard (SC) condition after which rats were either administered MTEP (1.0 mg/kg, ip) or saline prior to an acute (0.5 or 1.0 mg/kg, sc) or repeated (0.3 mg/kg, sc) amphetamine exposure. Rats undergoing repeated amphetamine exposure were administered MTEP prior to conditioned hyperactivity and sensitization tests. RESULTS EC and SC rats administered with MTEP prior to acute amphetamine demonstrated attenuated amphetamine-induced locomotor activity compared to controls, while IC rats administered MTEP following repeated amphetamine exposure demonstrated attenuated amphetamine-induced locomotor activity. Interestingly, MTEP treatment only altered conditioned hyperactivity in EC rats, as MTEP pretreatment resulted in conditioned hyperactivity in EC rats while conditioned hyperactivity was not observed in EC rats pretreated with saline. CONCLUSIONS Glutamatergic pathways are altered during differential rearing, which differentially alters the role of mGluR5 in EC, IC, and SC rats when administered psychostimulant acutely versus repeatedly. These findings suggest that differential rearing alters glutamatergic function, which reduces sensitivity to psychostimulants.
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Thiel KJ, Painter MR, Pentkowski NS, Mitroi D, Crawford CA, Neisewander JL. Environmental enrichment counters cocaine abstinence-induced stress and brain reactivity to cocaine cues but fails to prevent the incubation effect. Addict Biol 2012; 17:365-77. [PMID: 21812872 PMCID: PMC3220742 DOI: 10.1111/j.1369-1600.2011.00358.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Environmental enrichment (EE) during a period of forced abstinence attenuates incentive motivational effects of cocaine-paired stimuli. Here we examined whether EE during forced abstinence from cocaine self-administration would prevent time-dependent increases in cue-elicited cocaine-seeking behavior (i.e. the incubation effect). Rats were trained to self-administer cocaine, which was paired with light/tone cues, for 15 days while living in isolated conditions (IC). Controls received yoked saline infusions. Subsequently, rats were assigned to live in either continued IC or EE for either 1 or 21 days of forced abstinence prior to a test for cocaine-seeking behavior. During testing, responding resulted only in presentation of the light/tone cues. Contrary to our prediction, cocaine-seeking behavior increased over time regardless of living condition during abstinence; however, EE attenuated cocaine-seeking behavior relative to IC regardless of length of abstinence. Brains were harvested and trunk blood was collected immediately after the 60-minute test and later assayed. Results indicated that short-term EE elevated hippocampal brain-derived neurotrophic factor and reduced plasma corticosterone compared with IC. Furthermore, 21 days of EE during forced abstinence prevented increases in the cue-elicited amygdala phosphorylated extracellular signal-regulated kinase expression that was observed in IC rats. These findings suggest that EE attenuates incentive motivational effects of cocaine cues through a mechanism other than preventing the incubation effect, perhaps involving reduction of stress and neural activity in response to cocaine-paired cues during acute withdrawal.
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Affiliation(s)
- Kenneth J. Thiel
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104
| | - Michael R. Painter
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104
| | - Nathan S. Pentkowski
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104
- The School of Life Sciences, Arizona State University, P.O. Box 874501, Tempe, AZ 85287-4501
| | - Danut Mitroi
- Department of Psychology, California State University, San Bernardino, San Bernardino, CA 92407
| | - Cynthia A. Crawford
- Department of Psychology, California State University, San Bernardino, San Bernardino, CA 92407
| | - Janet L. Neisewander
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104
- The School of Life Sciences, Arizona State University, P.O. Box 874501, Tempe, AZ 85287-4501
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Briones TL, Rogozinska M, Woods J. Modulation of ischemia-induced NMDAR1 activation by environmental enrichment decreases oxidative damage. J Neurotrauma 2011; 28:2485-92. [PMID: 21612313 DOI: 10.1089/neu.2011.1842] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, we examined whether enriched environment (EE) housing has direct neuroprotective effects on oxidative damage following transient global cerebral ischemia. Fifty-two adult male Wistar rats were included in the study and received either ischemia or sham surgery. Once fully awake, rats in each group were randomly assigned to either: EE housing or socially paired housing (CON). Animals remained in their assigned environment for 7 days, and then were killed. Our data showed that glutamate receptor expression was significantly higher in the hippocampus of the ischemia CON group than in the ischemia EE group. Furthermore, the oxidative DNA damage, protein oxidation, and neurodegeneration in the hippocampus of the ischemia CON group were significantly increased compared to the ischemia EE group. These results suggest that EE housing possibly modulated the ischemia-induced glutamate excitotoxicity, which then attenuated the oxidative damage and neurodegeneration in the ischemia EE rats.
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Affiliation(s)
- Teresita L Briones
- Department of Adult Health, Wayne State University, Detroit, Michigan 48202, USA.
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17
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Wood DA, Walker TL, Rebec GV. Experience-dependent changes in neuronal processing in the nucleus accumbens shell in a discriminative learning task in differentially housed rats. Brain Res 2011; 1390:90-8. [PMID: 21420938 DOI: 10.1016/j.brainres.2011.03.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 03/04/2011] [Accepted: 03/09/2011] [Indexed: 11/30/2022]
Abstract
Environmental enrichment is associated with enhanced learning of complex tasks, attenuated seeking of natural and drug rewards, and altered function of the nucleus accumbens (NAcc), a brain region involved in goal-directed behavior. For example, during acquisition of a discriminative learning task, neurons in the NAcc core subregion are more responsive to discrete, goal-directed movements in rats raised in an enriched condition (EC) relative to an isolated condition (IC), but as learning materialized, this enhanced responsiveness shifts to the cues that predict these movements. Here, we report that these results do not extend to NAcc shell: neuronal responses in this subregion are similar in EC and IC rats during goal-directed movement and the presentation of associative cues both during and after task acquisition. With experience in this task, however, the overall proportion of task-related neuronal responses in NAcc shell decreases. The response pattern of shell neurons is also sensitive to the presence of contextual cues: shell neuronal firing reveals a significant shift from a predominant excitatory to a predominant inhibitory profile in probe trials when the cue that predicts sucrose availability is absent. Collectively, these data suggest that NAcc shell neurons encode cues associated with natural reward, are less responsive during appetitive behavior in familiar conditions, and are insensitive to appetitive learning differences expressed in rats reared in different environmental conditions.
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Affiliation(s)
- David A Wood
- Department of Neurology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, CLS 717, Boston, MA 02215, USA
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18
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Wilber AA, Lin GL, Wellman CL. Neonatal corticosterone administration impairs adult eyeblink conditioning and decreases glucocorticoid receptor expression in the cerebellar interpositus nucleus. Neuroscience 2011; 177:56-65. [PMID: 21223994 DOI: 10.1016/j.neuroscience.2011.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 01/04/2011] [Accepted: 01/05/2011] [Indexed: 11/18/2022]
Abstract
Neonatal maternal separation alters adult learning and memory. Previously, we showed that neonatal separation impaired eyeblink conditioning in adult rats and increased glucocorticoid receptor (GR) expression in the cerebellar interpositus nucleus, a critical site of learning-related plasticity. Daily neonatal separation (1 h/day on postnatal days 2-14) increases neonatal plasma corticosterone levels. Therefore, effects of separation on GR expression in the interpositus and consequently adult eyeblink conditioning may be mediated by neonatal increases in corticosterone. As a first step in exploring a potential role for corticosterone in the neonatal separation effects we observed, we assessed whether systemic daily (postnatal days 2-14) corticosterone injections mimic neonatal separation effects on adult eyeblink conditioning and GR expression in the interpositus. Control uninjected animals were compared to animals receiving either daily corticosterone injections or daily injections of an equal volume of vehicle. Plasma corticosterone values were measured in a separate group of control, neonatally separated, vehicle injected, or corticosterone injected pups. In adulthood, rats underwent surgery for implantation of recording and stimulating electrodes. After recovery from surgery, rats underwent 10 daily sessions of eyeblink conditioning. Then, brains were processed for GR immunohistochemistry and GR expression in the interpositus nucleus was assessed. Vehicle and corticosterone injections both produced much larger increases in neonatal plasma corticosterone than did daily maternal separation, with the largest increases occurring in the corticosterone-injected group. Neonatal corticosterone injections impaired adult eyeblink conditioning and decreased GR expression in the interpositus nucleus, while the effects of vehicle injections were intermediate. Thus, while neonatal injections and maternal separation both produce adult impairments in learning and memory, these manipulations produce opposite changes in GR expression. This suggests an inverted U-shaped relationship may exist between both neonatal corticosterone levels and adult GR expression in the interpositus nucleus, and adult GR expression in the interpositus and eyeblink conditioning.
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MESH Headings
- Aging/drug effects
- Aging/physiology
- Animals
- Animals, Newborn
- Cerebellar Nuclei/drug effects
- Cerebellar Nuclei/metabolism
- Conditioning, Eyelid/drug effects
- Conditioning, Eyelid/physiology
- Corticosterone/administration & dosage
- Corticosterone/blood
- Disease Models, Animal
- Female
- Male
- Maternal Deprivation
- Rats
- Rats, Long-Evans
- Receptors, Glucocorticoid/antagonists & inhibitors
- Receptors, Glucocorticoid/biosynthesis
- Receptors, Glucocorticoid/deficiency
- Stress, Psychological/metabolism
- Stress, Psychological/physiopathology
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Affiliation(s)
- A A Wilber
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, 4401 University Drive West, Lethbridge, AB, Canada T1K 3M4.
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19
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Environmental enrichment increases the in vivo extracellular concentration of dopamine in the nucleus accumbens: a microdialysis study. J Neural Transm (Vienna) 2010; 117:1123-30. [DOI: 10.1007/s00702-010-0447-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 07/09/2010] [Indexed: 01/13/2023]
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20
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Grilli M, Zappettini S, Zanardi A, Lagomarsino F, Pittaluga A, Zoli M, Marchi M. Exposure to an enriched environment selectively increases the functional response of the pre-synaptic NMDA receptors which modulate noradrenaline release in mouse hippocampus. J Neurochem 2009; 110:1598-606. [DOI: 10.1111/j.1471-4159.2009.06265.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Wilber A, Wellman C. Neonatal maternal separation-induced changes in glucocorticoid receptor expression in posterior interpositus interneurons but not projection neurons predict deficits in adult eyeblink conditioning. Neurosci Lett 2009; 460:214-8. [DOI: 10.1016/j.neulet.2009.05.076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 05/18/2009] [Accepted: 05/29/2009] [Indexed: 10/20/2022]
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22
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Wilber A, Wellman C. Neonatal maternal separation alters the development of glucocorticoid receptor expression in the interpositus nucleus of the cerebellum. Int J Dev Neurosci 2009; 27:649-54. [PMID: 19665541 DOI: 10.1016/j.ijdevneu.2009.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 07/17/2009] [Accepted: 08/02/2009] [Indexed: 10/20/2022] Open
Affiliation(s)
- A.A. Wilber
- Department of Psychological and Brain Sciences, and Program in NeuroscienceIndiana University1101 East 10th StreetBloomingtonIN47405United States
| | - C.L. Wellman
- Department of Psychological and Brain Sciences, and Program in NeuroscienceIndiana University1101 East 10th StreetBloomingtonIN47405United States
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23
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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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24
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Environmental enrichment alters neuronal processing in the nucleus accumbens core during appetitive conditioning. Brain Res 2008; 1259:59-67. [PMID: 19135429 DOI: 10.1016/j.brainres.2008.12.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 12/04/2008] [Accepted: 12/05/2008] [Indexed: 11/22/2022]
Abstract
Although the core region of the nucleus accumbens (NAcc) has been implicated in motor control and the acquisition of appetitive learning, these processes are altered by environmental experience. To assess how environment influences neuronal processing in NAcc core, we recorded single-unit activity during acquisition of an appetitive learning task in which rats reared in an environmentally enriched condition (EC) learned the operant response (nosepoke into a lit hole) for sucrose reinforcement faster than rats reared in an isolated condition (IC). In the first training session, even before the emergence of learning differences, core neurons were more likely to respond (increase or decrease activity) during the operant and consummatory responses in EC than IC rats. By the third training session, when learning differences emerged, EC neurons continued to be more responsive than IC neurons, but in very different ways: the response shifted to the cues that signaled trial onset (1900 Hz tone and green LED) and reward availability (4500 Hz tone and yellow LED). Cue-related responding, moreover, was dominated by neuronal excitations. In contrast, post-acquisition recordings revealed no EC-IC differences. Collectively, these results suggest that core neurons are initially more responsive to discrete, goal-directed movements in EC rats, but as learning materializes, the neuronal response shifts to the cues that predict these movements. Thus, environmental experience alters core neuronal processing of both motor- and sensory-related events but at different stages over the course of learning.
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25
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Rahman S, Bardo MT. Environmental enrichment increases amphetamine-induced glutamate neurotransmission in the nucleus accumbens: a neurochemical study. Brain Res 2008; 1197:40-6. [PMID: 18242591 PMCID: PMC2293327 DOI: 10.1016/j.brainres.2007.12.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 12/18/2007] [Accepted: 12/26/2007] [Indexed: 10/22/2022]
Abstract
In addition to dopamine (DA), evidence indicates that glutamatergic regulation of the mesolimbic reward pathway is involved in mediating the abuse-related effects of psychostimulants, including amphetamine. Since rats raised in an enrichment condition (EC) during development are more sensitive to the locomotor stimulant effects of acute amphetamine compared to rats raised in an impoverished condition (IC), the present study examined amphetamine-induced extracellullar glutamate and aspartate levels in the nucleus accumbens (NAcc) of EC and IC rats using in vivo microdialysis coupled with HPLC-electrochemical detection. Basal extracellular levels of glutamate or aspartate were not significantly different between EC and IC rats. Acute systemic amphetamine (0.5 or 2.0 mg/kg, sc) increased extracellular glutamate levels in NAcc of EC rats (137% or 305% of basal) and IC rats (120% or 187% of basal). Similarly, acute systemic amphetamine (0.5 or 2.0 mg/kg, sc) elevated aspartate levels in NAcc of EC rats (148% or 237% of basal) and IC rats (115% or 170% of basal). Glutamate levels were elevated by amphetamine to a greater extent in EC rats than in IC rats. Pretreatment with systemic MK-801 (0.25 mg/kg, ip), a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, prevented the acute amphetamine-induced increase in extracellular glutamate and aspartate levels in NAcc. Overall, these results suggest that alterations in glutamate in the NAcc may be involved in the environment-dependent effects of amphetamine.
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Affiliation(s)
- Shafiqur Rahman
- Center for Drug Abuse Research Translation, University of Kentucky, BBSRB, Room 447, 741 S. Limestone, Lexington, KY 40536-0509, USA.
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26
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Rahman S, Bardo MT. Environmental enrichment increases amphetamine-induced glutamate neurotransmission in the nucleus accumbens: A neurochemical study. Brain Res 2008. [DOI: https://doi.org/10.1016/j.brainres.2007.12.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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Miller BR, Dorner JL, Shou M, Sari Y, Barton SJ, Sengelaub DR, Kennedy RT, Rebec GV. Up-regulation of GLT1 expression increases glutamate uptake and attenuates the Huntington's disease phenotype in the R6/2 mouse. Neuroscience 2008; 153:329-37. [PMID: 18353560 DOI: 10.1016/j.neuroscience.2008.02.004] [Citation(s) in RCA: 228] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 02/01/2008] [Accepted: 02/01/2008] [Indexed: 12/29/2022]
Abstract
The striatum, which processes cortical information for behavioral output, is a key target of Huntington's disease (HD), an autosomal dominant condition characterized by cognitive decline and progressive loss of motor control. Increasing evidence implicates deficient glutamate uptake caused by a down-regulation of GLT1, the primary astroglial glutamate transporter. To test this hypothesis, we administered ceftriaxone, a beta-lactam antibiotic known to elevate GLT1 expression (200 mg/kg, i.p., for 5 days), to symptomatic R6/2 mice, a widely studied transgenic model of HD. Relative to vehicle, ceftriaxone attenuated several HD behavioral signs: paw clasping and twitching were reduced, while motor flexibility, as measured in a plus maze, and open-field climbing were increased. Assessment of GLT1 expression in striatum confirmed a ceftriaxone-induced increase relative to vehicle. To determine if the change in behavior and GLT1 expression represented a change in striatal glutamate handling, separate groups of behaving mice were evaluated with no-net-flux microdialysis. Vehicle treatment revealed a glutamate uptake deficit in R6/2 mice relative to wild-type controls that was reversed by ceftriaxone. Vehicle-treated animals, however, did not differ in GLT1 expression, suggesting that the glutamate uptake deficit in R6/2 mice reflects dysfunctional rather than missing GLT1. Our results indicate that impaired glutamate uptake is a major factor underlying HD pathophysiology and symptomology. The glutamate uptake deficit, moreover, is present in symptomatic HD mice and reversal of this deficit by up-regulating the functional expression of GLT1 with ceftriaxone attenuates the HD phenotype.
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Affiliation(s)
- B R Miller
- Program in Neuroscience, Department of Psychological and Brain Sciences, 1101 East 10th Street, Bloomington, IN 47405, USA
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28
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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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29
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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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30
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Wood DA, Siegel AK, Rebec GV. Environmental enrichment reduces impulsivity during appetitive conditioning. Physiol Behav 2006; 88:132-7. [PMID: 16678224 DOI: 10.1016/j.physbeh.2006.03.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 03/23/2006] [Accepted: 03/24/2006] [Indexed: 10/24/2022]
Abstract
Although environmental enrichment is presumed to enhance learning, appetitive behavior may also be altered by this experience: anticipatory responding for sucrose is reduced in environmentally enriched (EE) rats [van der Harst, J.E., Baars, A.M. and Spruijt, B.M. Standard housed rats are more sensitive to rewards than enriched housed rats as reflected by their anticipatory behaviour. Behav Brain Res 2003;142:151-156]. To assess the impact of differential environmental experience on learning and appetitive behavior, we trained 17 EE and socially isolated (SI) rats in a three-phase, operant-shaping procedure for sucrose reinforcement. In phase one, a feeder cue was paired with sucrose availability. In phase two, a nose poke to either one of two lit holes on the opposing wall activated the feeder cue. In phase three, the feeder cue was elicited by a poke to a single lit hole. While acquisition rates in phase one and phase two were similar, EE animals reached phase-three criteria [completion of 100 trials in 45 min and 15 or fewer bad pokes] faster than SI animals. These two groups showed similar session completion rates, reinforced and non-reinforced licking responses, and overall behavioral activity during phase three acquisition; however, SI rats performed more bad pokes (responses to the non-lit hole after nose-poke cue onset) and intertrial interval (ITI) pokes during this training period. Because all ITI (and presumably many bad) pokes were initiated before onset of nose-poke cue, this difference indicates greater anticipatory responding in SI animals. This experience-dependent alteration in appetitive behavior may explain, in part, the tendency of SI rats to show attenuated learning rates in appetitive contexts in which complex contingencies exist.
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Affiliation(s)
- David A Wood
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, 1101 E. Tenth Street, Bloomington, Indiana 47405-7007, USA
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31
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Garrett JE, Kim I, Wilson RE, Wellman CL. Effect of N-methyl-d-aspartate receptor blockade on plasticity of frontal cortex after cholinergic deafferentation in rat. Neuroscience 2006; 140:57-66. [PMID: 16529871 DOI: 10.1016/j.neuroscience.2006.01.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 01/16/2006] [Accepted: 01/26/2006] [Indexed: 10/24/2022]
Abstract
Cholinergic projections from the nucleus basalis play a critical role in cortical plasticity. For instance, cholinergic deafferentation increases dendritic spine density and expression of the GluR1 subunit of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor in frontal cortex. Acetylcholine modulates glutamatergic activity in cortex, and the N-methyl-d-aspartate subtype of glutamate receptor plays a role in many forms of synaptic plasticity. To assess whether N-methyl-d-aspartate receptors mediate the increase in GluR1 and spine density resulting from cholinergic deafferentation, we examined the effect of N-methyl-d-aspartate receptor blockade on nucleus basalis lesion-induced upregulation of GluR1 and dendritic spines. Rats received unilateral sham or 192 IgG saporin lesions of the nucleus basalis. Half of the rats in each group were treated with the N-methyl-d-aspartate antagonist MK-801 or phosphate-buffered saline. Two weeks later, brains were processed for either immunohistochemical staining of the GluR1 subunit or Golgi histology. In layer II-III of frontal cortex, neuronal GluR1 expression was assessed using an unbiased stereological technique, and spine density was assessed on basilar branches of pyramidal neurons. GluR1 expression was increased after nucleus basalis lesion, but this increase was prevented with MK-801. Similarly, nucleus basalis-lesioned animals had significantly higher spine densities, and this effect was also prevented by treatment with MK-801. Thus, N-methyl-d-aspartate receptor blockade prevented both GluR1 and spine density upregulation following cholinergic deafferentation, suggesting that these effects are N-methyl-d-aspartate receptor-mediated.
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Affiliation(s)
- J E Garrett
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
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