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Enriched and deprived sensory experience induces structural changes and rewires connectivity during the postnatal development of the brain. Neural Plast 2012; 2012:305693. [PMID: 22848849 PMCID: PMC3400395 DOI: 10.1155/2012/305693] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 03/20/2012] [Accepted: 06/13/2012] [Indexed: 11/17/2022] Open
Abstract
During postnatal development, sensory experience modulates cortical development, inducing numerous changes in all of the components of the cortex. Most of the cortical changes thus induced occur during the critical period, when the functional and structural properties of cortical neurons are particularly susceptible to alterations. Although the time course for experience-mediated sensory development is specific for each system, postnatal development acts as a whole, and if one cortical area is deprived of its normal sensory inputs during early stages, it will be reorganized by the nondeprived senses in a process of cross-modal plasticity that not only increases performance in the remaining senses when one is deprived, but also rewires the brain allowing the deprived cortex to process inputs from other senses and cortices, maintaining the modular configuration. This paper summarizes our current understanding of sensory systems development, focused specially in the visual system. It delineates sensory enhancement and sensory deprivation effects at both physiological and anatomical levels and describes the use of enriched environment as a tool to rewire loss of brain areas to enhance other active senses. Finally, strategies to apply restorative features in human-deprived senses are studied, discussing the beneficial and detrimental effects of cross-modal plasticity in prostheses and sensory substitution devices implantation.
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102
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Pang TYC, Hannan AJ. Enhancement of cognitive function in models of brain disease through environmental enrichment and physical activity. Neuropharmacology 2012; 64:515-28. [PMID: 22766390 DOI: 10.1016/j.neuropharm.2012.06.029] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/06/2012] [Accepted: 06/15/2012] [Indexed: 12/21/2022]
Abstract
This review will provide an overview of the non-drug based approaches that have been demonstrated to enhance cognitive function of the compromised brain, primarily focussed on the two most widely adopted paradigms of environmental enrichment and enhanced physical exercise. Environmental enrichment involves the generation of novelty and complexity in animal housing conditions which facilitates enhanced sensory and cognitive stimulation as well as physical activity. In a wide variety of animal models of brain disorders, environmental enrichment and exercise have been found to have beneficial effects, including cognitive enhancement, delayed disease onset, enhanced cellular plasticity and associated molecular processes. Potential cellular and molecular mechanisms will also be discussed, which have relevance for the future development of 'enviromimetics', drugs which could mimic or enhance the beneficial effects of environmental stimulation. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Terence Y C Pang
- Florey Neuroscience Institutes, Melbourne Brain Centre, University of Melbourne, Parkville, VIC 3010, Australia.
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103
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Cechetti F, Worm PV, Lovatel G, Moysés F, Siqueira IR, Netto CA. Environmental enrichment prevents behavioral deficits and oxidative stress caused by chronic cerebral hypoperfusion in the rat. Life Sci 2012; 91:29-36. [PMID: 22683434 DOI: 10.1016/j.lfs.2012.05.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 04/25/2012] [Accepted: 05/19/2012] [Indexed: 12/31/2022]
Abstract
AIMS The aim of the present study was to evaluate the neuroprotective effects of environmental enrichment (EE), assessed by cognitive activity in the Morris water maze, and on brain oxidative status, through measurement of macromolecules damage, lipid peroxidation levels, total cellular thiols and antioxidant enzymes in hippocampus, striatum and cerebral cortex. MAIN METHODS Adult male Wistar rats were submitted to the modified permanent bilateral occlusion of the common carotid arteries (2VO) method, with right common carotid artery being first occluded, and tested three months after the ischemic event. Cognitive and physical stimulation, named Environmental Enrichment, consisted of one-hour sessions run 3 times per week during 12weeks, following two different stimulation protocols: pre-ischemia and pre+post-ischemia. Rats were then tested for both reference and working spatial memory tasks in the water maze and later sacrificed for measurement of oxidative stress parameters. KEY FINDINGS A significant cognitive deficit was found in both spatial tasks after hypoperfusion; this effect was reversed in the 2VO enriched group. Moreover, hippocampal oxidative damage and antioxidant enzyme activity were decreased by environmental enrichment. SIGNIFICANCE These results suggest that both stimulation protocols exert a neuroprotective effect against the cognitive impairment and the reduction of biomarkers for oxidative damage caused by chronic cerebral hypoperfusion.
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Affiliation(s)
- Fernanda Cechetti
- Programa de Pós-graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil.
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Goldberg NR, Fields V, Pflibsen L, Salvatore MF, Meshul CK. Social enrichment attenuates nigrostriatal lesioning and reverses motor impairment in a progressive 1-methyl-2-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. Neurobiol Dis 2012; 45:1051-67. [DOI: 10.1016/j.nbd.2011.12.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 10/29/2011] [Accepted: 12/04/2011] [Indexed: 11/29/2022] Open
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Abstract
BACKGROUND AND PURPOSE Aerobic and strengthening exercises have been shown to benefit people with Parkinson's disease (PD) on the basis of highly structured, short-term, clinical protocols. This study extended previous research by investigating feasibility of an ongoing, community-based, group exercise program for people with PD on the basis of short-term (10 weeks) and long-term (14 months) data. METHODS Twenty people with PD (Hoehn and Yahr stages I to III) participated in at least one of four 10-week sessions. Classes were held twice weekly for 1 hour and included strength, flexibility, and balance and walking exercises. Evaluations were done 1.5 hours after medication intake 1 week before and 1 week after each session. Gait speed, 6-Minute Walk test (6MWT), "Timed Up and Go" test, and grip strength were used to assess physical function. Analysis of short-term results were based on 18 participants (2 dropped out prior to posttest), and long-term results were based on 8 participants who started in the first session continued through the 14-month period. RESULTS Attendance rates were moderate to high (73% overall). No injuries were reported. Wilcoxon signed ranks tests based on each participant's first 10-week session demonstrated significant improvements in 6MWT, and grip strength. Long-term participants showed significant improvements in grip strength, and a trend toward improved 6MWT. Gait speed and Timed Up and Go test did not change significantly in the short or long terms. DISCUSSION/CONCLUSIONS Our community-based group exercise program was safe, feasible, and appears to be effective. While some measures showed no improvement, there was no evidence of decline. This is an important outcome for persons with progressive neurological disorders, and suggests community-based group exercise is a promising option for people with PD.
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106
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Jiao Y, Lu L, Williams RW, Smeyne RJ. Genetic dissection of strain dependent paraquat-induced neurodegeneration in the substantia nigra pars compacta. PLoS One 2012; 7:e29447. [PMID: 22291891 PMCID: PMC3265472 DOI: 10.1371/journal.pone.0029447] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 11/28/2011] [Indexed: 02/03/2023] Open
Abstract
The etiology of the vast majority of Parkinson's disease (PD) cases is unknown. It is generally accepted that there is an interaction between exposures to environmental agents with underlying genetic sensitivity. Recent epidemiological studies have shown that people living in agricultural communities have an increased risk of PD. Within these communities, paraquat (PQ) is one of the most utilized herbicides. PQ acts as a direct redox cycling agent to induce formation of free radicals and when administered to mice induces the cardinal symptoms of parkinsonism, including loss of TH+-positive dopaminergic (DA) neurons in the ventral midbrain's substantia nigra pars compacta (SNpc). Here we show that PQ-induced SNpc neuron loss is highly dependent on genetic background: C57BL/6J mice rapidly lose ∼50% of their SNpc DA neurons, whereas inbred Swiss-Webster (SWR/J) mice do not show any significant loss. We intercrossed these two strains to map quantitative trait loci (QTLs) that underlie PQ-induced SNpc neuron loss. Using genome-wide linkage analysis we detected two significant QTLs. The first is located on chromosome 5 (Chr 5) centered near D5Mit338, whereas the second is on Chr 14 centered near D14Mit206. These two QTLs map to different loci than a previously identified QTL (Mptp1) that controls a significant portion of strain sensitivity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), suggesting that the mechanism of action of these two parkinsonian neurotoxins are different.
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Affiliation(s)
- Yun Jiao
- Department of Developmental Neurobiology, Saint Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Lu Lu
- Department of Anatomy and Neurobiology, Center for Integrative and Translational Genomics, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Robert W. Williams
- Department of Anatomy and Neurobiology, Center for Integrative and Translational Genomics, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Richard J. Smeyne
- Department of Developmental Neurobiology, Saint Jude Children's Research Hospital, Memphis, Tennessee, United States of America
- * E-mail:
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De Bartolo P, Gelfo F, Burello L, De Giorgio A, Petrosini L, Granato A. Plastic changes in striatal fast-spiking interneurons following hemicerebellectomy and environmental enrichment. THE CEREBELLUM 2012; 10:624-32. [PMID: 21509479 DOI: 10.1007/s12311-011-0275-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Recent findings suggest marked interconnections between the cerebellum and striatum, thus challenging the classical view of their segregated operation in motor control. Therefore, this study was aimed at further investigating this issue by analyzing the effects of hemicerebellectomy (HCb) on density and dendritic length of striatal fast-spiking interneurons (FSi). First, we analyzed the plastic rearrangements of striatal FSi morphology in hemicerebellectomized animals reared in standard conditions. Then, since environmental enrichment (EE) induces structural changes in experimental models of brain disease, we evaluated FSi morphology in lesioned animals exposed to an enriched environment after HCb. Although HCb did not affect FSi density, it progressively shrank dendritic branching of striatal FSi of both sides. These plastic changes, already evident 15 days after the cerebellar ablation, became very marked 30 days after the lesion. Such a relevant effect was completely abolished by postoperative enrichment. EE not only counteracted shrinkage of FSi dendritic arborization but also provoked a progressive increase in dendritic length which surpassed that of the controls as the enrichment period lengthened. These data confirm that the cerebellum and striatum are more interconnected than previously retained. Furthermore, cerebellar damage likely evokes a striatal response through cortical mediation. The EE probably modifies HCb-induced plastic changes in the striatum by increasing the efficiency of the cortical circuitry. This is the first study describing the morphological rearrangement of striatal FSi following a cerebellar lesion; it provides the basis for further studies aimed at investigating the mechanisms underlying cerebello-striatal "talking."
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Affiliation(s)
- Paola De Bartolo
- IRCCS S. Lucia Foundation, via del Fosso di Fiorano 64, 00164, Rome, Italy.
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108
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Fontes-Ribeiro CA, Marques E, Pereira FC, Silva AP, Macedo TRA. May exercise prevent addiction? Curr Neuropharmacol 2011; 9:45-8. [PMID: 21886560 PMCID: PMC3137199 DOI: 10.2174/157015911795017380] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 04/17/2010] [Accepted: 05/26/2010] [Indexed: 11/23/2022] Open
Abstract
Amphetamines exert their persistent addictive effects by activating brain's reward pathways, perhaps through the release of dopamine in the nucleus accumbens (and/or in other places). On the other hand, there is a relationship between dopamine and all behavioural aspects that involve motor activity and it has been demonstrated that exercise leads to an increase in the synthesis and release of dopamine, stimulates neuroplasticity and promotes feelings of well-being. Moreover, exercise and drugs of abuse activate overlapping neural systems. Thus, our aim was to study the influence of chronic exercise in the mechanism of addiction using an amphetamine-induced conditioned-place-preference in rats. Adult male Sprague-Dawley rats were randomly separated in groups with and without chronic exercise. Chronic exercise consisted in a 8 week treadmill running program, with increasing intensity. The conditioned place preference test was performed in both groups using a procedure and apparatus previously established. A 2 mg.kg-1 amphetamine or saline solution was administered intraperitonially according to the schedule of the conditioned place preference. Before conditioning none of the animals showed preference for a specific compartment of the apparatus. The used amphetamine dose in the conditioning phase was able to produce a marked preference towards the drug-associated compartment in the group without exercise. In the animals with exercise a significant preference by the compartment associated with saline was observed. These results lead us to conclude that a previous practice of regular physical activity may help preventing amphetamine addiction in the conditions used in this test.
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Affiliation(s)
- C A Fontes-Ribeiro
- Institute of Pharmacology and Experimental Therapeutics, Biomedical Institute for Research on Light and Image (IBILI), Faculty of Medicine; Association for Biomedical Research and Innovation on Light and Image (AIBILI); 3000 Coimbra, Portugal
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Emack J, Matthews SG. Effects of chronic maternal stress on hypothalamo-pituitary-adrenal (HPA) function and behavior: no reversal by environmental enrichment. Horm Behav 2011; 60:589-98. [PMID: 21907201 DOI: 10.1016/j.yhbeh.2011.08.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 08/12/2011] [Accepted: 08/12/2011] [Indexed: 11/24/2022]
Abstract
Maternal stress during pregnancy is linked to increased risk for impaired behavioral and emotional development and affective disorders in children. In animal models, acute periods of prenatal or postnatal stress have profound effects on HPA function and behavior in adult offspring. However, few animal studies have determined the impact of chronic exposure to stress throughout the perinatal period. The objective of this study was to determine the effects of chronic maternal stress (CMS) during the 2nd half of pregnancy and nursing on HPA function, locomotor behavior and prepulse inhibition in adult guinea pig offspring, as well as to determine whether environmental enrichment (EE) could reverse the effects of CMS. Guinea pigs were exposed to a random combination of variable stressors every other day over the 2nd half of gestation and from postnatal day (pnd) 1 until weaning (pnd25). Following weaning, offspring were housed in either standard conditions or EE. In both adult male and female offspring, there was no effect of CMS on basal or activated HPA function. CMS significantly increased locomotor activity in an open-field in male offspring, though no effect was observed in females. In female offspring, CMS disrupted PPI; however there was no effect on male PPI. EE had a number of effects on HPA function and behavior but in most cases these were independent of the influence of CMS. EE significantly elevated basal cortisol levels in male offspring at pnd70, whereas in female offspring, EE interacted with CMS to elevate basal cortisol levels from pnd35 to pnd70. In female offspring, EE decreased locomotor activity. In males, EE enhanced PPI; however in female offspring EE disrupted PPI. In conclusion, while CMS had minimal effects on HPA function, there were significant long-term sex-specific effects on behavior. EE did not reverse the effects observed as a result of CMS, but rather modified HPA function and behavior independently of CMS. Further, there was significant interaction of CMS with EE that resulted in elevation of basal HPA function in female offspring. These data, combined with previous studies from our laboratory, suggest that acute phases of maternal stress in late pregnancy may have greater long-term effects on HPA function and related behaviors than prolonged chronic maternal stress.
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Affiliation(s)
- Jeff Emack
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
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111
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El Ayadi A, Zigmond MJ. Low concentrations of methamphetamine can protect dopaminergic cells against a larger oxidative stress injury: mechanistic study. PLoS One 2011; 6:e24722. [PMID: 22022363 PMCID: PMC3192034 DOI: 10.1371/journal.pone.0024722] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 08/19/2011] [Indexed: 11/19/2022] Open
Abstract
Mild stress can protect against a larger insult, a phenomenon termed preconditioning or tolerance. To determine if a low intensity stressor could also protect cells against intense oxidative stress in a model of dopamine deficiency associated with Parkinson disease, we used methamphetamine to provide a mild, preconditioning stress, 6-hydroxydopamine (6-OHDA) as a source of potentially toxic oxidative stress, and MN9D cells as a model of dopamine neurons. We observed that prior exposure to subtoxic concentrations of methamphetamine protected these cells against 6-OHDA toxicity, whereas higher concentrations of methamphetamine exacerbated it. The protection by methamphetamine was accompanied by decreased uptake of both [(3)H] dopamine and 6-OHDA into the cells, which may have accounted for some of the apparent protection. However, a number of other effects of methamphetamine exposure suggest that the drug also affected basic cellular survival mechanisms. First, although methamphetamine preconditioning decreased basal pERK1/2 and pAkt levels, it enhanced the 6-OHDA-induced increase in these phosphokinases. Second, the apparent increase in pERK1/2 activity was accompanied by increased pMEK1/2 levels and decreased activity of protein phosphatase 2. Third, methamphetamine upregulated the pro-survival protein Bcl-2. Our results suggest that exposure to low concentrations of methamphetamine cause a number of changes in dopamine cells, some of which result in a decrease in their vulnerability to subsequent oxidative stress. These observations may provide insights into the development of new therapies for prevention or treatment of PD.
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Affiliation(s)
- Amina El Ayadi
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Michael J. Zigmond
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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Hirsch MA, Iyer SS, Englert D, Sanjak M. Promoting exercise in Parkinson's disease through community-based participatory research. Neurodegener Dis Manag 2011; 1:365-377. [PMID: 22545069 PMCID: PMC3337755 DOI: 10.2217/nmt.11.44] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Parkinson's disease (PD) is a chronic, progressive, as-of-yet incurable, neurodegenerative condition affecting the nigro-striatal dopaminergic system. Emerging evidence suggests the importance of exercise in improving the trajectory of PD. Yet few people with PD are physically active. One challenge that healthcare professionals face in the 21st century is how to deliver physical activity programs to the population of individuals living with PD. A novel approach to delivering physical activity to people with PD is introduced - termed community-based participatory research (CBPR) - which engages people with PD and patient advocates as co-researchers in the development and implementation of community-based exercise programs. The authors describe the CBPR approach and provide several recent examples of community exercise programs that are steps in the direction of developing the CBPR model. This is followed by a discussion of what a more fully realized CBPR model might look like. Finally, the authors describe some obstacles to conducting CBPR and suggest strategies for overcoming them. It is argued that people with PD are an integral component of delivering the exercise intervention.
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Affiliation(s)
- Mark A Hirsch
- Carolinas Rehabilitation, Carolinas Medical Center, Department of Physical Medicine & Rehabilitation, 1100 Blythe Blvd, Charlotte, NC 28203, USA
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113
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Kane JR, Ciucci MR, Jacobs AN, Tews N, Russell JA, Ahrens AM, Ma ST, Britt JM, Cormack LK, Schallert T. Assessing the role of dopamine in limb and cranial-oromotor control in a rat model of Parkinson's disease. JOURNAL OF COMMUNICATION DISORDERS 2011; 44:529-37. [PMID: 21820129 PMCID: PMC3278988 DOI: 10.1016/j.jcomdis.2011.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
UNLABELLED Parkinson's disease (PD) is a neurodegenerative disorder primarily characterized by sensorimotor dysfunction. The neuropathology of PD includes a loss of dopamine (DA) neurons of the nigrostriatal pathway. Classic signs of the disease include rigidity, bradykinesia, and postural instability. However, as many as 90% of patients also experience significant deficits in speech, swallowing (including mastication), and respiratory control. Oromotor deficits such as these are underappreciated, frequently emerging during the early, often hemi-Parkinson, stage of the disease. In this paper, we review tests commonly used in our labs to model early and hemi-Parkinson deficits in rodents. We have recently expanded our tests to include sensitive models of oromotor deficits. This paper discusses the most commonly used tests in our lab to model both limb and oromotor deficits, including tests of forelimb-use asymmetry, postural instability, vibrissae-evoked forelimb placing, single limb akinesia, dry pasta handling, sunflower seed shelling, and acoustic analyses of ultrasonic vocalizations and pasta biting strength. In particular, we lay new groundwork for developing methods for measuring abnormalities in the acoustic patterns during eating that indicate decreased biting strength and irregular intervals between bites in the hemi-Parkinson rat. Similar to limb motor deficits, oromotor deficits, at least to some degree, appear to be modulated by nigrostriatal DA. Finally, we briefly review the literature on targeted motor rehabilitation effects in PD models. LEARNING OUTCOMES Readers will: (a) understand how a unilateral lesion to the nigrostriatal pathway affects limb use, (b) understand how a unilateral lesion to the nigrostriatal pathway affects oromotor function, and (c) gain an understanding of how limb motor deficits and oromotor deficits appear to involve dopamine and are modulated by training.
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Affiliation(s)
- Jacqueline R Kane
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA.
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Lindemann L, Jaeschke G, Michalon A, Vieira E, Honer M, Spooren W, Porter R, Hartung T, Kolczewski S, Büttelmann B, Flament C, Diener C, Fischer C, Gatti S, Prinssen EP, Parrott N, Hoffmann G, Wettstein JG. CTEP: a novel, potent, long-acting, and orally bioavailable metabotropic glutamate receptor 5 inhibitor. J Pharmacol Exp Ther 2011; 339:474-86. [PMID: 21849627 DOI: 10.1124/jpet.111.185660] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The metabotropic glutamate receptor 5 (mGlu5) is a glutamate-activated class C G protein-coupled receptor widely expressed in the central nervous system and clinically investigated as a drug target for a range of indications, including depression, Parkinson's disease, and fragile X syndrome. Here, we present the novel potent, selective, and orally bioavailable mGlu5 negative allosteric modulator with inverse agonist properties 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1H-imidazol-4-yl)ethynyl)pyridine (CTEP). CTEP binds mGlu5 with low nanomolar affinity and shows >1000-fold selectivity when tested against 103 targets, including all known mGlu receptors. CTEP penetrates the brain with a brain/plasma ratio of 2.6 and displaces the tracer [(3)H]3-(6-methyl-pyridin-2-ylethynyl)-cyclohex-2-enone-O-methyl-oxime (ABP688) in vivo in mice from brain regions expressing mGlu5 with an average ED(50) equivalent to a drug concentration of 77.5 ng/g in brain tissue. This novel mGlu5 inhibitor is active in the stress-induced hyperthermia procedure in mice and the Vogel conflict drinking test in rats with minimal effective doses of 0.1 and 0.3 mg/kg, respectively, reflecting a 30- to 100-fold higher in vivo potency compared with 2-methyl-6-(phenylethynyl)pyridine (MPEP) and fenobam. CTEP is the first reported mGlu5 inhibitor with both long half-life of approximately 18 h and high oral bioavailability allowing chronic treatment with continuous receptor blockade with one dose every 48 h in adult and newborn animals. By enabling long-term treatment through a wide age range, CTEP allows the exploration of the full therapeutic potential of mGlu5 inhibitors for indications requiring chronic receptor inhibition.
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Affiliation(s)
- Lothar Lindemann
- F. Hoffmann-La Roche Ltd. Pharmaceuticals Division, Discovery Neuroscience, Grenzacherstrasse 124, 4070 Basel, Switzerland.
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115
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“Brain training” improves cognitive performance and survival in a transgenic mouse model of Huntington's disease. Neurobiol Dis 2011; 42:427-37. [DOI: 10.1016/j.nbd.2011.02.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/04/2011] [Accepted: 02/08/2011] [Indexed: 01/17/2023] Open
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Mechanisms mediating brain and cognitive reserve: experience-dependent neuroprotection and functional compensation in animal models of neurodegenerative diseases. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:331-9. [PMID: 21112312 DOI: 10.1016/j.pnpbp.2010.10.026] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 10/13/2010] [Accepted: 10/29/2010] [Indexed: 01/01/2023]
Abstract
'Brain and cognitive reserve' (BCR) refers here to the accumulated neuroprotective reserve and capacity for functional compensation induced by the chronic enhancement of mental and physical activity. BCR is thought to protect against, and compensate for, a range of different neurodegenerative diseases, as well as other neurological and psychiatric disorders. In this review we will discuss BCR, and its potential mechanisms, in neurodegenerative disorders, with a focus on Huntington's disease (HD) and Alzheimer's disease (AD). Epidemiological studies of AD, and other forms of dementia, provided early evidence for BCR. The first evidence for the beneficial effects of enhanced mental and physical activity, and associated mechanistic insights, in an animal model of neurodegenerative disease was provided by experiments using HD transgenic mice. More recently, experiments on animal models of HD, AD and various other brain disorders have suggested potential molecular and cellular mechanisms underpinning BCR. We propose that sophisticated insight into the processes underlying BCR, and identification of key molecules mediating these beneficial effects, will pave the way for therapeutic advances targeting these currently incurable neurodegenerative diseases.
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Peneder TM, Scholze P, Berger ML, Reither H, Heinze G, Bertl J, Bauer J, Richfield EK, Hornykiewicz O, Pifl C. Chronic exposure to manganese decreases striatal dopamine turnover in human alpha-synuclein transgenic mice. Neuroscience 2011; 180:280-92. [PMID: 21333719 DOI: 10.1016/j.neuroscience.2011.02.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 02/01/2011] [Accepted: 02/09/2011] [Indexed: 12/20/2022]
Abstract
Interaction of genetic and environmental factors is likely involved in Parkinson's disease (PD). Mutations and multiplications of alpha-synuclein (α-syn) cause familial PD, and chronic manganese (Mn) exposure can produce an encephalopathy with signs of parkinsonism. We exposed male transgenic C57BL/6J mice expressing human α-syn or the A53T/A30P doubly mutated human α-syn under the tyrosine hydroxylase promoter and non-transgenic littermates to MnCl₂-enriched (1%) or control food, starting at the age of 4 months. Locomotor activity was increased by Mn without significant effect of the transgenes. Mice were sacrificed at the age of 7 or 20 months. Striatal Mn was significantly increased about three-fold in those exposed to MnCl₂. The number of tyrosine hydroxylase positive substantia nigra compacta neurons was significantly reduced in 20 months old mice (-10%), but Mn or transgenes were ineffective (three-way ANOVA with the factors gene, Mn and age). In 7 months old mice, striatal homovanillic acid (HVA)/dopamine (DA) ratios and aspartate levels were significantly increased in control mice with human α-syn as compared to non-transgenic controls (+17 and +11%, respectively); after Mn exposure both parameters were significantly reduced (-16 and -13%, respectively) in human α-syn mice, but unchanged in non-transgenic animals and mice with mutated α-syn (two-way ANOVA with factors gene and Mn). None of the parameters were changed in the 20 months old mice. Single HVA/DA ratios and single aspartate levels significantly correlated across all treatment groups suggesting a causal relationship between the rate of striatal DA metabolism and aspartate release. In conclusion, under our experimental conditions, Mn and human α-syn, wild-type and doubly mutated, did not interact to induce PD-like neurodegenerative changes. However, Mn significantly and selectively interacted with human wild-type α-syn on indices of striatal DA neurotransmission, the neurotransmitter most relevant to PD.
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Affiliation(s)
- T M Peneder
- Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
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Archer T, Fredriksson A, Johansson B. Exercise alleviates Parkinsonism: clinical and laboratory evidence. Acta Neurol Scand 2011; 123:73-84. [PMID: 21108623 DOI: 10.1111/j.1600-0404.2010.01360.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The present review examines the putative benefits for individuals afflicted with Parkinsonism, whether in the clinical setting or in the animal laboratory, accruing from different exercise regimes. The tendency for patients with Parkinson's disease (PD) to express either normal or reduced exercise capacity appears regulated by factors such as fatigue, quality-of-life and disorder severity. The associations between physical exercise and risk for PD, the effects of exercise on idiopathic Parkinsonism and quality-of-life, the effects of exercise on animal laboratory models of Parkinsonism and dopamine (DA) loss following neurotoxic insults, and the effects of exercise on the DA precursor, L-Dopa, efficacy are examined. It would appear to be case that in view of the particular responsiveness of the dopaminergic neurons to exercise, the principle of 'use it or lose' may be of special applicability among PD patients.
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Affiliation(s)
- T Archer
- Department of Psychology, University of Gothenburg, Sweden.
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119
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Haaxma C, Helmich R, Borm G, Kappelle A, Horstink M, Bloem B. Side of symptom onset affects motor dysfunction in Parkinson's disease. Neuroscience 2010; 170:1282-5. [DOI: 10.1016/j.neuroscience.2010.07.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/21/2010] [Accepted: 07/15/2010] [Indexed: 12/16/2022]
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120
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Enriched environment promotes similar neuronal and behavioral recovery in a young and aged mouse model of Parkinson's disease. Neuroscience 2010; 172:443-52. [PMID: 20933577 DOI: 10.1016/j.neuroscience.2010.09.062] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 09/30/2010] [Indexed: 01/15/2023]
Abstract
Environmental enrichment has been shown to be neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease (PD). Because PD patients are not typically diagnosed until later neuropathological stages, the current study investigated the capacity of an enriched environment (EE) to stimulate restoration of neurons in the substantia nigra pars compacta (SNpc) and locomotor recovery after lesioning, as opposed to before. A low-dose chronic MPTP regimen was used to achieve a partial, less severe lesion of the nigrostriatal pathway not seen in acute MPTP models. Both young adult (10 weeks) and aged (12 months) C57BL/6J male mice were used to assess the effects of aging on recovery with EE intervention. After the first week of either MPTP (7 mg/kg/d in young; 5 mg/kg/d in aged) or saline injection, animals from both groups were housed in a standard environment (SE) or an EE for 3 weeks, with continued daily administration of MPTP. We are the first to report that following 3 weeks exposure to an EE, young and aged MPTP-lesioned mice showed a significant 53% and 52% restoration of tyrosine hydroxylase (TH)-labeled neurons in the SNpc, respectively. This increase in TH-labeled cells in the MPTP+EE group was correlated with recovery of free-standing rear (FSR) behavior in both age groups; however, improved locomotor control as measured by foot faults (FF) per total activity was only seen in the aged MPTP+EE group. Our data demonstrate that an EE promotes neurorestoration in TH protein expression in SNpc neurons as well as some locomotor recovery in both young and aged animals in this mouse model of PD.
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121
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Sozda CN, Hoffman AN, Olsen AS, Cheng JP, Zafonte RD, Kline AE. Empirical comparison of typical and atypical environmental enrichment paradigms on functional and histological outcome after experimental traumatic brain injury. J Neurotrauma 2010; 27:1047-57. [PMID: 20334496 DOI: 10.1089/neu.2010.1313] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Several studies have shown that housing rats in an enriched environment (EE) after traumatic brain injury (TBI) improves functional and histological outcome. The typical EE includes exploratory, sensory, and social components in cages that are often vastly larger than standard (STD) housing. It is uncertain, however, whether a single or specific component is sufficient to confer these benefits after TBI, or if all, perhaps in an additive or synergistic manner, are necessary. To clarify this ambiguity, anesthetized adult male rats were subjected to either a controlled cortical impact or sham injury, and then were randomly assigned to five different housing paradigms: (1) EE (typical), (2) EE (-social), (3) EE (-stimuli), (4) STD (typical), and (5) STD (+stimuli). Motor and cognitive function were assessed using conventional motor (beam-balance/traversal) and cognitive (spatial learning in a Morris water maze) tests on postoperative days 1-5 and 14-19, respectively, and cortical lesion volume and CA1/CA3 cell loss were quantified at 3 weeks. No significant differences were observed among the sham groups in any comparison and thus their data were pooled (i.e., SHAM). In the TBI groups, typical EE improved beam-balance versus both STD (+stimuli) and EE (-social), it facilitated the acquisition of spatial learning and memory retention versus all other housing conditions (p < 0.003), and it reduced lesion volume and CA3 cell loss versus STD (typical) housing. While rats in the three atypical EE conditions exhibited slightly better cognitive performance and histological protection versus the typical STD group, the overall effects were not significant. These data suggest that exposing TBI rats to any of the three components individually may be more advantageous than no enrichment, but only exposure to typical EE yields optimal benefits.
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Affiliation(s)
- Christopher N Sozda
- Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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122
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Reynolds S, Lane SJ, Richards L. Using animal models of enriched environments to inform research on sensory integration intervention for the rehabilitation of neurodevelopmental disorders. J Neurodev Disord 2010; 2:120-32. [PMID: 22127899 PMCID: PMC3164047 DOI: 10.1007/s11689-010-9053-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 05/28/2010] [Indexed: 01/09/2023] Open
Abstract
The field of behavioral neuroscience has been successful in using an animal model of enriched environments for over five decades to measure the rehabilitative and preventative effects of sensory, cognitive and motor stimulation in animal models. Several key principles of enriched environments match those used in sensory integration therapy, a treatment used for children with neurodevelopmental disorders. This paper reviews the paradigm of environmental enrichment, compares animal models of enriched environments to principles of sensory integration treatment, and discusses applications for the rehabilitation of neurodevelopmental disorders. Based on this review, the essential features in the enriched environment paradigm which should be included in sensory integration treatment are multiple sensory experiences, novelty in the environment, and active engagement in challenging cognitive, sensory, and motor tasks. Use of sensory integration treatment may be most applicable for children with anxiety, hypersensitivity, repetitive behaviors or heightened levels of stress. Additionally, individuals with deficits in social behavior, social participation, or impairments in learning and memory may show gains with this type of treatment.
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Affiliation(s)
- Stacey Reynolds
- Department of Occupational Therapy, School of Allied Health Professions, Virginia Commonwealth University, Box 980008, Richmond, VA, 23298, USA,
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123
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Kyriazis M. Nonlinear Stimulation and Hormesis in Human Aging: Practical Examples and Action Mechanisms. Rejuvenation Res 2010; 13:445-52. [DOI: 10.1089/rej.2009.0996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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124
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Triggering endogenous neuroprotective processes through exercise in models of dopamine deficiency. Parkinsonism Relat Disord 2010; 15 Suppl 3:S42-5. [PMID: 20083005 DOI: 10.1016/s1353-8020(09)70778-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We are testing the hypothesis that exercise is neuroprotective in animal models of the dopamine (DA) deficiency in Parkinson's disease. Our studies include mice or rats provided access to a running wheel and subsequently treated with MPTP (mice) or 6-hydroxydopamine (rats) and monkeys provided access to a treadmill and subsequently treated with MPTP. Typically, the exercise occurs for 3 months prior to the toxin treatment and often for 1-2 months thereafter. Our findings indicate that exercise reduces the behavioral impairments elicited by the dopaminergic neurotoxins as well as the loss of DA neurons as assessed by PET imaging and biochemical or histochemical assessment of tissue samples. Our studies are focused on one of several possible explanations for the beneficial effects of exercise: an exercise-induced increase in the expression of neurotrophic factors, particularly GDNF. Our observations indicate that GDNF can reduce the vulnerability of DA neurons, in part due to the activation of key intracellular cascades. We also find that mild cellular stress itself can provide protection against more intensive stress, a form of preconditioning. We conclude that dopamine neurons have the capacity to respond to intracellular and extracellular signals by triggering endogenous neuroprotective mechanisms. This raises the possibility that some individuals with Parkinson's disease suffer from a reduction of these neuroprotective mechanisms, and that treatments that boost these mechanisms - including exercise - may provide therapeutic benefit.
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125
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Russell JA, Ciucci MR, Connor NP, Schallert T. Targeted exercise therapy for voice and swallow in persons with Parkinson's disease. Brain Res 2010; 1341:3-11. [PMID: 20233583 DOI: 10.1016/j.brainres.2010.03.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 03/08/2010] [Indexed: 01/09/2023]
Abstract
Sensorimotor deficits affecting voice and swallowing ability can have a devastating impact on the quality of life of people with Parkinson disease (PD). Recent scientific findings in animal models of PD pinpoint targeted exercise therapy as a potential treatment to reduce neurochemical loss and decrease parkinsonian symptoms. Although there may be beneficial effects, targeted exercise therapy is not a standard component of therapy for the cranial sensiromotor deficits seen in PD. In this paper, we review the scientific evidence for targeted training for voice and swallowing deficits. The literature search revealed 19 publications that included targeted training for voice and only one publication that included targeted training for swallowing. We summarize 3 main findings: (1) targeted training may be associated with lasting changes in voice behavior; (2) targeted training of sensorimotor actions with anatomical or functional overlap with voice and swallowing may improve voice and swallowing to some degree, but it is unknown whether these effects endure over time; and (3) evidence regarding cranial sensorimotor interventions for Parkinson disease is sparse. We concluded that targeted training for voice and swallow is a promising but understudied intervention for cranial sensorimotor deficits associated with PD and posit that animal models can be useful in designing empirically based studies that further the science on targeted training.
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Affiliation(s)
- John A Russell
- University of Wisconsin School of Medicine and Public Health, Otolaryngology Head and Neck Surgery, USA.
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126
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Neurorééducation des syndromes parkinsoniens. Rev Neurol (Paris) 2010; 166:196-212. [DOI: 10.1016/j.neurol.2009.10.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/28/2009] [Indexed: 11/19/2022]
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127
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Gerecke KM, Jiao Y, Pani A, Pagala V, Smeyne RJ. Exercise protects against MPTP-induced neurotoxicity in mice. Brain Res 2010; 1341:72-83. [PMID: 20116369 DOI: 10.1016/j.brainres.2010.01.053] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 01/06/2010] [Accepted: 01/18/2010] [Indexed: 01/11/2023]
Abstract
Exercise has been shown to be potently neuroprotective in several neurodegenerative models, including 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) model of Parkinson's disease (PD). In order to determine the critical duration of exercise necessary for DA neuroprotection, mice were allowed to run for either 1, 2 or 3months prior to treatment with saline or MPTP. Quantification of DA neurons in the SNpc show that mice allowed to run unrestricted for 1 or 2months lost significant numbers of neurons following MPTP administration as compared to saline treated mice; however, 3months of exercise provided complete protection against MPTP-induced neurotoxicity. To determine the critical intensity of exercise for DA neuroprotection, mice were restricted in their running to either 1/3 or 2/3 that of the full running group for 3months prior to treatment with saline or MPTP. Quantification of DA neurons in the SNpc show that mice whose running was restricted lost significant numbers of DA neurons due to MPTP toxicity; however, the 2/3 running group demonstrated partial protection. Neurochemical analyses of DA and its metabolites DOPAC and HVA show that exercise also functionally protects neurons from MPTP-induced neurotoxicity. Proteomic analysis of SN and STR tissues indicates that 3months of exercise induces changes in proteins related to energy regulation, cellular metabolism, the cytoskeleton, and intracellular signaling events. Taken together, these data indicate that exercise potently protects DA neurons from acute MPTP toxicity, suggesting that this simple lifestyle element may also confer significant protection against developing PD in humans.
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128
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Donlea JM, Shaw PJ. Sleeping together using social interactions to understand the role of sleep in plasticity. ADVANCES IN GENETICS 2010; 68:57-81. [PMID: 20109659 DOI: 10.1016/s0065-2660(09)68003-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Social experience alters the expression of genes related to synaptic function and plasticity, induces elaborations in the morphology of neural structures throughout the brain (Volkmar and Greenough, 1972; Greenough et al., 1978; Technau, 2007), improves cognitive and behavioral performance (Pham et al., 1999a; Toscano et al., 2006) and alters subsequent sleep (Ganguly-Fitzgerald et al., 2006). In this review, we discuss the plastic mechanisms that are induced in response to social experience and how social enrichment can provide insight into the biological functions of sleep.
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Affiliation(s)
- Jeffrey M Donlea
- Department of Anatomy and Neurobiology, Washington University School of Medicine, Campus Box 8108, St. Louis, Missouri, USA
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129
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Leasure JL, Nixon K. Exercise neuroprotection in a rat model of binge alcohol consumption. Alcohol Clin Exp Res 2009; 34:404-14. [PMID: 20028365 DOI: 10.1111/j.1530-0277.2009.01105.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Excessive alcohol intake produces structural and functional deficits in corticolimbic pathways that are thought to underlie cognitive deficits in the alcohol use disorders (AUDs). Animal models of binge alcohol administration support the direct link of high levels of alcohol consumption and neurotoxicity in the hippocampus and surrounding cortex. In contrast, voluntary wheel running enhances hippocampal neurogenesis and generally promotes the health of neurons. METHODS We investigated whether voluntary exercise prior to binge alcohol exposure could protect against alcohol-induced cell loss. Female Long-Evans rats exercised voluntarily for 14 days before undergoing 4 days of binge alcohol consumption. Brains were harvested immediately after the last dose of alcohol and examined for various histological markers of neurodegeneration, including both cell death (FluoroJade B) and cell birth (Ki67) markers. RESULTS Rats that exercised prior to binge exposure were significantly less behaviorally intoxicated, which was not a result of enhanced hepatic metabolism. Rats that exercised prior to binge alcohol consumption had reduced loss of dentate gyrus granule cells and fewer FluoroJade B positive cells in the dentate gyrus and associated entorhinal-perirhinal cortex compared to nonexercisers. However, exercise did not protect against cell death in the piriform cortex nor protect against alcohol-induced decreases in cell proliferation, evidenced by a similar alcohol-induced reduction in Ki67 labeled cells between exercise and sedentary rats. CONCLUSIONS We conclude that exercise can reduce behavioral sensitivity to ethanol intoxication and protect vulnerable brain areas from alcohol-induced cell death. Exercise neuroprotection of alcohol-induced brain damage has important implications in understanding the neurobiology of the AUDs as well as in developing novel treatment strategies.
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Affiliation(s)
- J Leigh Leasure
- Department of Psychology, University of Houston, Houston, Texas, USA
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130
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Nithianantharajah J, Hannan AJ. The neurobiology of brain and cognitive reserve: mental and physical activity as modulators of brain disorders. Prog Neurobiol 2009; 89:369-82. [PMID: 19819293 DOI: 10.1016/j.pneurobio.2009.10.001] [Citation(s) in RCA: 227] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/16/2009] [Accepted: 10/01/2009] [Indexed: 12/23/2022]
Abstract
The concept of 'cognitive reserve', and a broader theory of 'brain reserve', were originally proposed to help explain epidemiological data indicating that individuals who engaged in higher levels of mental and physical activity via education, occupation and recreation, were at lower risk of developing Alzheimer's disease and other forms of dementia. Subsequently, behavioral, cellular and molecular studies in animals (predominantly mice and rats) have revealed dramatic effects of environmental enrichment, which involves enhanced levels of sensory, cognitive and motor stimulation via housing in novel, complex environments. Furthermore, increasing levels of voluntary physical exercise, via ad libitum access to running wheels, can have significant effects on brain and behavior, thus informing the relative effects of mental and physical activity. More recently, animal models of brain disorders have been compared under environmentally stimulating and standard housing conditions, and this has provided new insights into environmental modulators and gene-environment interactions involved in pathogenesis. Here, we review animal studies that have investigated the effects of modifying mental and physical activity via experimental manipulations, and discuss their relevance to brain and cognitive reserve (BCR). Recent evidence suggests that the concept of BCR is not only relevant to brain aging, neurodegenerative diseases and dementia, but also to other neurological and psychiatric disorders. Understanding the cellular and molecular mechanisms mediating BCR may not only facilitate future strategies aimed at optimising healthy brain aging, but could also identify molecular targets for novel pharmacological approaches aimed at boosting BCR in 'at risk' and symptomatic individuals with various brain disorders.
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Affiliation(s)
- Jess Nithianantharajah
- Howard Florey Institute, Florey Neuroscience Institutes, University of Melbourne, Victoria 3010, Australia
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131
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Increased Concentrations of Nerve Growth Factor and Brain-Derived Neurotrophic Factor in the Rat Cerebellum After Exposure to Environmental Enrichment. THE CEREBELLUM 2009; 8:499-506. [DOI: 10.1007/s12311-009-0129-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 08/03/2009] [Indexed: 12/28/2022]
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132
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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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133
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Zhu J, Reith MEA. Role of the dopamine transporter in the action of psychostimulants, nicotine, and other drugs of abuse. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2009; 7:393-409. [PMID: 19128199 DOI: 10.2174/187152708786927877] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A number of studies over the last two decades have demonstrated the critical importance of dopamine (DA) in the behavioral pharmacology and addictive properties of abused drugs. The DA transporter (DAT) is a major target for drugs of abuse in the category of psychostimulants, and for methylphenidate (MPH), a drug used for treating attention deficit hyperactivity disorder (ADHD), which can also be a psychostimulant drug of abuse. Other drugs of abuse such as nicotine, ethanol, heroin and morphine interact with the DAT in more indirect ways. Despite the different ways in which drugs of abuse can affect DAT function, one evolving theme in all cases is regulation of the DAT at the level of surface expression. DAT function is dynamically regulated by multiple intracellular and extracellular signaling pathways and several protein-protein interactions. In addition, DAT expression is regulated through the removal (internalization) and recycling of the protein from the cell surface. Furthermore, recent studies have demonstrated that individual differences in response to novel environments and psychostimulants can be predicted based on individual basal functional DAT expression. Although current knowledge of multiple factors regulating DAT activity has greatly expanded, many aspects of this regulation remain to be elucidated; these data will enable efforts to identify drugs that might be used therapeutically for drug dependence therapeutics.
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Affiliation(s)
- J Zhu
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA.
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134
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Guillot TS, Miller GW. Protective actions of the vesicular monoamine transporter 2 (VMAT2) in monoaminergic neurons. Mol Neurobiol 2009; 39:149-70. [PMID: 19259829 DOI: 10.1007/s12035-009-8059-y] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 02/18/2009] [Indexed: 12/13/2022]
Abstract
Vesicular monoamine transporters (VMATs) are responsible for the packaging of neurotransmitters such as dopamine, serotonin, norepinephrine, and epinephrine into synaptic vesicles. These proteins evolved from precursors in the major facilitator superfamily of transporters and are among the members of the toxin extruding antiporter family. While the primary function of VMATs is to sequester neurotransmitters within vesicles, they can also translocate toxicants away from cytosolic sites of action. In the case of dopamine, this dual role of VMAT2 is combined-dopamine is more readily oxidized in the cytosol where it can cause oxidative stress so packaging into vesicles serves two purposes: neurotransmission and neuroprotection. Furthermore, the deleterious effects of exogenous toxicants on dopamine neurons, such as MPTP, can be attenuated by VMAT2 activity. The active metabolite of MPTP can be kept within vesicles and prevented from disrupting mitochondrial function thereby sparing the dopamine neuron. The highly addictive drug methamphetamine is also neurotoxic to dopamine neurons by using dopamine itself to destroy the axon terminals. Methamphetamine interferes with vesicular sequestration and increases the production of dopamine, escalating the amount in the cytosol and leading to oxidative damage of terminal components. Vesicular transport seems to resist this process by sequestering much of the excess dopamine, which is illustrated by the enhanced methamphetamine neurotoxicity in VMAT2-deficient mice. It is increasingly evident that VMAT2 provides neuroprotection from both endogenous and exogenous toxicants and that while VMAT2 has been adapted by eukaryotes for synaptic transmission, it is derived from phylogenetically ancient proteins that originally evolved for the purpose of cellular protection.
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Affiliation(s)
- Thomas S Guillot
- Center for Neurodegenerative Disease, Emory University, Atlanta, GA, USA
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135
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Anastasía A, Torre L, de Erausquin GA, Mascó DH. Enriched environment protects the nigrostriatal dopaminergic system and induces astroglial reaction in the 6-OHDA rat model of Parkinson's disease. J Neurochem 2009; 109:755-65. [PMID: 19245661 DOI: 10.1111/j.1471-4159.2009.06001.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Enriched environment (EE) is neuroprotective in several animal models of neurodegeneration. It stimulates the expression of trophic factors and modifies the astrocyte cell population which has been said to exert neuroprotective effects. We have investigated the effects of EE on 6-hydroxydopamine (6-OHDA)-induced neuronal death after unilateral administration to the medial forebrain bundle, which reaches 85-95% of dopaminergic neurons in the substantia nigra after 3 weeks. Continuous exposure to EE 3 weeks before and after 6-OHDA injection prevents neuronal death (assessed by tyrosine hydroxylase staining), protects the nigrostriatal pathway (assessed by Fluorogold retrograde labeling) and reduces motor impairment. Four days after 6-OHDA injection, EE was associated with a marked increase in glial fibrillary acidic protein staining and prevented neuronal death (assessed by Fluoro Jade-B) but not partial loss of tyrosine hydroxylase staining in the anterior substantia nigra. These results robustly demonstrate that EE preserves the entire nigrostriatal system against 6-OHDA-induced toxicity, and suggests that an early post-lesion astrocytic reaction may participate in the neuroprotective mechanism.
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Affiliation(s)
- Agustín Anastasía
- Facultad de Ciencias Exactas, Centro de Biología Celular y Molecular, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
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136
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Penn PR, Rose FD, Johnson DA. Virtual enriched environments in paediatric neuropsychological rehabilitation following traumatic brain injury: Feasibility, benefits and challenges. Dev Neurorehabil 2009; 12:32-43. [PMID: 19283532 DOI: 10.1080/17518420902739365] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A frequent consequence of traumatic brain injury (TBI) is a significant reduction in patients' cerebral activation/arousal, which clinicians agree is not conducive to optimal rehabilitation outcomes. In the context of paediatric rehabilitation, sustained periods of inactivity are particularly undesirable, as contemporary research has increasingly called into question the Kennard principle that youth inherently promotes greater neural plasticity and functional recovery following TBI. Therefore, the onus to create rehabilitation conditions most conducive to harnessing plasticity falls squarely on the shoulders of clinicians. Having noted the efficacy of environmental enrichment in promoting neural plasticity and positive functional outcomes in the animal literature, some researchers have suggested that the emerging technology of Virtual Reality (VR) could provide the means to increase patients' cerebral activation levels via the use of enriched Virtual Environments (VEs). However, 10 years on, this intuitively appealing concept has received almost no attention from researchers and clinicians alike. This paper overviews recent research on the benefits of enriched environments in the injured brain and identifies the potential and challenges associated with implementing VR-based enrichment in paediatric neuropsychological rehabilitation.
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Affiliation(s)
- P R Penn
- School of Psychology, University of East London, Stratford, London, UK.
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137
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Jadavji N, Metz G. Both pre- and post-lesion experiential therapy is beneficial in 6-hydroxydopamine dopamine-depleted female rats. Neuroscience 2009; 158:373-86. [DOI: 10.1016/j.neuroscience.2008.10.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 10/29/2008] [Accepted: 11/02/2008] [Indexed: 01/25/2023]
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138
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Marques E, Vasconcelos F, Rolo MR, Pereira FC, Silva AP, Macedo TR, Ribeiro CF. Influence of chronic exercise on the amphetamine-induced dopamine release and neurodegeneration in the striatum of the rat. Ann N Y Acad Sci 2008; 1139:222-31. [PMID: 18991868 DOI: 10.1196/annals.1432.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aim of this study was to verify the effect of chronic exercise on the striatal dopamine (DA) outflow induced by low and high single doses of amphetamine (AMPH), and verify the existence of an exercise protective role on neurodegeneration. Adult male Sprague-Dawley rats were randomly separated into six groups: chronic exercise, saline; chronic exercise, 5 mg kg(-1) AMPH; chronic exercise, 30 mg kg(-1) AMPH; without exercise, saline; without exercise, 5 mg kg(-1) AMPH; without exercise, 30 mg kg(-1) AMPH. Chronic exercise consisted of an 8-week running program on a treadmill, with increasing intensity. Animals were anesthetized, placed into a stereotaxic frame and an intracerebral guide cannula implanted into the caudate-putamen. When indicated, microdialysis was performed. Dialysate samples were collected during 30-min intervals for 6 h, before and after the intraperitonial administration of AMPH or saline solution. HPLC with electrochemical detection was used to quantify DA. Chronic exercise did not significantly change the extracellular DA basal values. Regarding the maximal DA levels in the dialysates, in the rats treated with 5 mg kg(-1) AMPH, there was no significant difference between groups with and without chronic exercise; on the contrary, in animals treated with 30 mg kg(-1) AMPH, the DA release was lower in the group with chronic exercise. Moreover, the maintenance of higher levels of DA along time in the training group suggests a diminished reuptake of DA. By using the Fluoro-Jade C staining technique, we did not find neuronal death in any of the groups. In conclusion, these results suggest that chronic exercise leads to a diminished release and reuptake of DA after administration of a high dose of AMPH, whereas neither chronic exercise nor AMPH seems to induce neurodegeneration.
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Affiliation(s)
- Elsa Marques
- Department of Pharmacology, Biomedical Institute for Research on Light and Image (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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139
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Castro-Caldas M, Neves Carvalho A, Peixeiro I, Rodrigues E, Lechner MC, Gama MJ. GSTpi expression in MPTP-induced dopaminergic neurodegeneration of C57BL/6 mouse midbrain and striatum. J Mol Neurosci 2008; 38:114-27. [PMID: 18792812 DOI: 10.1007/s12031-008-9141-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Accepted: 07/29/2008] [Indexed: 11/29/2022]
Abstract
MPTP-induced dopaminergic neurotoxicity involves major biochemical processes such as oxidative stress and impaired energy metabolism, leading to a significant reduction in the number of nigrostriatal dopaminergic neurons. Glutathione S-transferase pi (GSTpi) is a phase II detoxifying enzyme that provides protection of cells from injury by toxic chemicals and products of oxidative stress. In humans, polymorphisms of GSTP1 affect substrate selectivity and stability increasing the susceptibility to parkinsonism-inducing effects of environmental toxins. Given the ability of MPTP to increase the levels of reactive oxygen species and the link between altered redox potential and the expression and activity of GSTpi, we investigated the effect of MPTP on GSTpi cellular concentration in an in vivo model of Parkinson's disease. The present study demonstrates that GSTpi is actively expressed in both substantia nigra pars compacta and striatum of C57BL/6 mice brain, mostly in oligodendrocytes and astrocytes. After systemic administration of MPTP, GSTpi expression is significantly increased in glial cells in the vicinity of dopaminergic neurons cell bodies and fibers. The results suggest that GSTpi expression may be part of the mechanism underlying the ability of glial cells to elicit protection against the mechanisms involved in MPTP-induced neuronal death.
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Affiliation(s)
- Margarida Castro-Caldas
- Research Institute for Medicines and Pharmaceutical Sciences-iMED.UL, University of Lisbon, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal
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140
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Saavedra A, Baltazar G, Duarte EP. Driving GDNF expression: the green and the red traffic lights. Prog Neurobiol 2008; 86:186-215. [PMID: 18824211 DOI: 10.1016/j.pneurobio.2008.09.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 06/18/2008] [Accepted: 09/03/2008] [Indexed: 01/28/2023]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is widely recognized as a potent survival factor for dopaminergic neurons of the nigrostriatal pathway that degenerate in Parkinson's disease (PD). In animal models of PD, GDNF delivery to the striatum or the substantia nigra protects dopaminergic neurons against subsequent toxin-induced injury and rescues previously damaged neurons, promoting recovery of the motor function. Thus, GDNF was proposed as a potential therapy to PD aimed at slowing down, halting or reversing neurodegeneration, an issue addressed in previous reviews. However, the use of GDNF as a therapeutic agent for PD is hampered by the difficulty in delivering it to the brain. Another potential strategy is to stimulate the endogenous expression of GDNF, but in order to do that we need to understand how GDNF expression is regulated. The aim of this review is to do a comprehensive analysis of the state of the art on the control of endogenous GDNF expression in the nervous system, focusing mainly on the nigrostriatal pathway. We address the control of GDNF expression during development, in the adult brain and after injury, and how damaged neurons signal glial cells to up-regulate GDNF. Pharmacological agents or natural molecules that increase GDNF expression and show neuroprotective activity in animal models of PD are reviewed. We also provide an integrated overview of the signalling pathways linking receptors for these molecules to the induction of GDNF gene, which might also become targets for neuroprotective therapies in PD.
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Affiliation(s)
- Ana Saavedra
- Department of Cell Biology, Immunology and Neurosciences, Faculty of Medicine, University of Barcelona, Carrer Casanova 143, 08036 Barcelona, Spain.
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141
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Görtz N, Lewejohann L, Tomm M, Ambrée O, Keyvani K, Paulus W, Sachser N. Effects of environmental enrichment on exploration, anxiety, and memory in female TgCRND8 Alzheimer mice. Behav Brain Res 2008; 191:43-8. [DOI: 10.1016/j.bbr.2008.03.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 03/03/2008] [Accepted: 03/09/2008] [Indexed: 12/11/2022]
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142
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Nag N, Moriuchi JM, Peitzman CGK, Ward BC, Kolodny NH, Berger-Sweeney JE. Environmental enrichment alters locomotor behaviour and ventricular volume in Mecp2 1lox mice. Behav Brain Res 2008; 196:44-8. [PMID: 18687363 DOI: 10.1016/j.bbr.2008.07.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 07/08/2008] [Accepted: 07/10/2008] [Indexed: 11/15/2022]
Abstract
Rett syndrome (RTT) is an autistic spectrum developmental disorder associated with mutations in the X-linked Mecp2 gene, and severe behavioural and neuropathological deficits. In a mouse model of RTT (Mecp2(1lox)), we examined whether environmental enrichment (EE) alters behavioural performance and regional brain volume. At weaning, Mecp2(1lox) and control mice were assigned to enriched or standard housing. From postnatal day 29 to 43, mice were subjected to behavioural tasks measuring motor and cognitive performance. At postnatal day 44, volumes of whole brain, cerebellum, ventricles, and motor cortex were measured using magnetic resonance imaging. EE provided subtle improvements to locomotor activity and contextual fear conditioning in Mecp2(1lox) mice. Additionally, EE reduced ventricular volumes, which correlated with improved locomotor activity, suggesting that neuroanatomical changes contribute to improved behaviour. Our results suggest that post-weaning EE may provide a non-invasive palliative treatment for RTT.
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Affiliation(s)
- Nupur Nag
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA
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143
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Ciucci MR, Ma ST, Kane JR, Ahrens AM, Schallert T. Limb use and complex ultrasonic vocalization in a rat model of Parkinson's disease: deficit-targeted training. Parkinsonism Relat Disord 2008; 14 Suppl 2:S172-5. [PMID: 18585950 PMCID: PMC2737701 DOI: 10.1016/j.parkreldis.2008.04.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Recent evidence in animal models of Parkinson's disease (PD) suggests that exercise and other forms of motor enhancement can be beneficial when applied during the degeneration of dopamine neurons. Behaviours that depend on adequate levels of striatal dopamine may provide particularly favourable targets for therapeutic motor interventions. Task-specific motor enrichment procedures have been used to improve functional and neural outcomes following unilateral infusions of 6-hydroxydopamine (6-OHDA) into the nigrostriatal pathway in rats. In contrast, forced non-use procedures can exaggerate the degree of degeneration. Limb-use akinesia and ultrasonic vocalization in the 50-kHz range may be useful behavioural indices of nigrostriatal integrity and may model common deficits found in PD. These deficits in movement initiation and fine sensorimotor control are potential targets for early training interventions.
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Affiliation(s)
- Michelle R Ciucci
- Department of Psychology, University of Texas, 1 University Station A8000, Austin, TX 78712, USA
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144
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Goodwin VA, Richards SH, Taylor RS, Taylor AH, Campbell JL. The effectiveness of exercise interventions for people with Parkinson's disease: a systematic review and meta-analysis. Mov Disord 2008; 23:631-40. [PMID: 18181210 DOI: 10.1002/mds.21922] [Citation(s) in RCA: 542] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder affecting the physical, psychological, social, and functional status of individuals. Exercise programs may be an effective strategy to delay or reverse functional decline for people with PD and a large body of empirical evidence has emerged in recent years. The objective is to systematically review randomized controlled trials (RCTs) reporting on the effectiveness of exercise interventions on outcomes (physical, psychological or social functioning, or quality of life) for people with PD. RCTs meeting the inclusion criteria were identified by systematic searching of electronic databases. Key data were extracted by two independent researchers. A mixed methods approach was undertaken using narrative, vote counting, and random effects meta-analysis methods. Fourteen RCTs were included and the methodological quality of most studies was moderate. Evidence supported exercise as being beneficial with regards to physical functioning, health-related quality of life, strength, balance and gait speed for people with PD. There was insufficient evidence support or refute the value of exercise in reducing falls or depression. This review found evidence of the potential benefits of exercise for people with PD, although further good quality research is needed. Questions remain around the optimal content of exercise interventions (dosing, component exercises) at different stages of the disease.
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Affiliation(s)
- Victoria A Goodwin
- Primary Care Research Group, Peninsula Medical School, Exeter, United Kingdom.
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145
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Thiriet N, Amar L, Toussay X, Lardeux V, Ladenheim B, Becker KG, Cadet JL, Solinas M, Jaber M. Environmental enrichment during adolescence regulates gene expression in the striatum of mice. Brain Res 2008; 1222:31-41. [PMID: 18585688 DOI: 10.1016/j.brainres.2008.05.030] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 05/02/2008] [Accepted: 05/04/2008] [Indexed: 11/30/2022]
Abstract
We have previously shown that environmental enrichment decreases the activating and rewarding effects of the psychostimulant cocaine and increases resistance to the neurotoxic effect of the Parkinson-inducing drug MPTP. These effects were accompanied by an increase in the striatal expression of the neurotrophin BDNF, an increase in the striatal levels of delta-Fos B and by a decrease in striatal levels of the dopamine transporter, the main molecular target for cocaine and MPTP. Here, we used cDNA arrays to investigate the effects of rearing mice in enriched environments from weaning to adulthood on the profile of expression of genes in the striatum focusing on genes involved in intracellular signalling and functioning. We found that mice reared in an enriched environment show several alterations in the levels of mRNA coding for proteins involved in cell proliferation, cell differentiation, signal transduction, transcription and translation, cell structure and metabolism. Several of these findings were further confirmed by real-time quantitative PCR and, in the case of protein kinase C lambda, also by western blot. These findings are the first description of alterations in striatal gene expression by an enriched environment. The striatal gene expression regulation by environment that we report here may play a role in the resistance to the effects of drugs of abuse and dopaminergic neurotoxins previously reported.
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Affiliation(s)
- Nathalie Thiriet
- Institut de Biologie et Physiologie Cellulaires, University of Poitiers, 40 Avenue du Recteur Pineau, Poitiers, France
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146
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147
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Bellinger DC. Late neurodevelopmental effects of early exposures to chemical contaminants: reducing uncertainty in epidemiological studies. Basic Clin Pharmacol Toxicol 2008; 102:237-44. [PMID: 18226079 DOI: 10.1111/j.1742-7843.2007.00164.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Early exposures to environmental chemicals are reliably associated with late neurotoxicities in children. However, substantial scatter of observations exists around the estimated dose-effect relationships. This variability has many potential sources, one of which is interindividual differences in susceptibility. Such differences imply that the long-term impacts of exposure will not the same for all individuals, but will vary depending on a variety of factors that might either aggravate or mitigate contaminant effects. These include co-exposures, genetic polymorphisms and characteristics of the social environment. The context dependence of contaminant effects has implications both for study designs and analytical approaches. In addition, a systems approach to understanding the associations among contaminant exposures, covariates and health outcomes is necessary.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Children's Hospital Boston, Boston, MA 02115, USA.
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148
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Abstract
Animal models of movement disorders can present special challenges for the research institutions that use them. Such models often affect the animals' ability to ambulate and perform normal body functions, and these potential effects on health and well-being mandate additional steps to ensure humane animal care and use. Indeed, the appropriate level of care for these models may call for actions that go beyond what is required or considered standard for other protocols. A proactive team approach to animal use protocol development and animal management is important. Through the commitment and involvement of the entire team-researchers, facility personnel, and institutional animal care and use committee members--institutions that use these valuable models can ensure both the fulfillment of research objectives and the implementation of the best practices for animal care. Among the most commonly used animal models of movement disorder are models of stroke, brain and spinal cord injury, dystonia, Parkinson's disease, and Huntington's disease. Despite their relatively wide use, there is very little in the literature that describes the specific needs of individual models and the challenges those needs may present in today's regulatory environment. In this article, we discuss animal use considerations and provide the available animal care information on specific models. Interested readers are also referred to the additional information in the accompanying articles in this issue of ILAR Journal.
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Affiliation(s)
- Jeanne M Wallace
- Division of Animal Care, AA-6206 Medical Center North, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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149
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Anastasia A, de Erausquin GA, Wojnacki J, Mascó DH. Protection of dopaminergic neurons by electroconvulsive shock in an animal model of Parkinson’s disease. J Neurochem 2007; 103:1542-52. [PMID: 17854351 DOI: 10.1111/j.1471-4159.2007.04856.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Electroconvulsive shock (ECS) improves motor function in Parkinson's disease. In rats, ECS stimulates the expression of various factors some of which have been proposed to exert neuroprotective actions. We have investigated the effects of ECS on 6-hydroxydopamine (6-OHDA)-injected rats. Three weeks after a unilateral administration of 6-OHDA, 85-95% nigral dopaminergic neurons are lost. Chronic ECS prevented this cell loss, protect the nigrostriatal pathway (assessed by FloroGold retrograde labeling) and reduce motor impairment in 6-OHDA-treated animals. Injection of 6-OHDA caused loss of expression of glial cell-line derived neurotrophic factor (GDNF) in the substantia nigra. Chronic ECS completely prevented this loss of GDNF expression in 6-OHDA-treated animals. We also found that protected dopaminergic neurons co-express GDNF receptor proteins. These results strongly suggest that endogenous changes in GDNF expression may participate in the neuroprotective mechanism of ECS against 6-OHDA induced toxicity.
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Affiliation(s)
- Agustín Anastasia
- Centro de Biología Celular y Molecular. F.C.E.F.y N. Universidad Nacional de Córdoba, Córdoba, Argentina
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150
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Maguire-Zeiss KA, Mhyre TR, Federoff HJ. Gazing into the future: Parkinson's disease gene therapeutics to modify natural history. Exp Neurol 2007; 209:101-13. [PMID: 18035353 DOI: 10.1016/j.expneurol.2007.09.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 09/19/2007] [Accepted: 09/24/2007] [Indexed: 12/21/2022]
Abstract
PD gene therapy clinical trials have primarily focused on increasing the production of dopamine (DA) through supplemental amino acid decarboxylase (AADC) expression, neurotrophic support for surviving dopaminergic neurons (DAN) or altering brain circuitry to compensate for DA neuron loss. The future of PD gene therapy will depend upon resolving a number of important issues that are discussed in this special issue. Of particular importance is the identification of novel targets that are amenable to early intervention prior to the substantial loss of DAN. However, for the most part the etiopathogenesis of PD is unknown making early intervention a challenge and the development of early biomarker diagnostics imperative.
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