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Salgado-Puga K, Rothschild G. Exposure to sounds during sleep impairs hippocampal sharp wave ripples and memory consolidation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568283. [PMID: 38045371 PMCID: PMC10690295 DOI: 10.1101/2023.11.22.568283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Sleep is critical for the consolidation of recent experiences into long-term memories. As a key underlying neuronal mechanism, hippocampal sharp-wave ripples (SWRs) occurring during sleep define periods of hippocampal reactivation of recent experiences and have been causally linked with memory consolidation. Hippocampal SWR-dependent memory consolidation during sleep is often referred to as occurring during an "offline" state, dedicated to processing internally generated neural activity patterns rather than external stimuli. However, the brain is not fully disconnected from the environment during sleep. In particular, sounds heard during sleep are processed by a highly active auditory system which projects to brain regions in the medial temporal lobe, reflecting an anatomical pathway for sound modulation of hippocampal activity. While neural processing of salient sounds during sleep, such as those of a predator or an offspring, is evolutionarily adaptive, whether ongoing processing of environmental sounds during sleep interferes with SWR-dependent memory consolidation remains unknown. To address this question, we used a closed-loop system to deliver non-waking sound stimuli during or following SWRs in sleeping rats. We found that exposure to sounds during sleep suppressed the ripple power and reduced the rate of SWRs. Furthermore, sounds delivered during SWRs (On-SWR) suppressed ripple power significantly more than sounds delivered 2 seconds after SWRs (Off-SWR). Next, we tested the influence of sound presentation during sleep on memory consolidation. To this end, SWR-triggered sounds were applied during sleep sessions following learning of a conditioned place preference paradigm, in which rats learned a place-reward association. We found that On-SWR sound pairing during post-learning sleep induced a complete abolishment of memory retention 24 h following learning, while leaving memory retention immediately following sleep intact. In contrast, Off-SWR pairing weakened memory 24 h following learning as well as immediately following learning. Notably, On-SWR pairing induced a significantly larger impairment in memory 24 h after learning as compared to Off-SWR pairing. Together, these findings suggest that sounds heard during sleep suppress SWRs and memory consolidation, and that the magnitude of these effects are dependent on sound-SWR timing. These results suggest that exposure to environmental sounds during sleep may pose a risk for memory consolidation processes.
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Narvaes RF, Nachtigall EG, Marcondes LA, Izquierdo I, Myskiw JDC, Furini CR. Involvement of medial prefrontal cortex canonical Wnt/β-catenin and non-canonical Wnt/Ca2+ signaling pathways in contextual fear memory in male rats. Behav Brain Res 2022; 430:113948. [DOI: 10.1016/j.bbr.2022.113948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 04/25/2022] [Accepted: 05/24/2022] [Indexed: 11/02/2022]
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Schaan Fernandes H, Popik B, de Oliveira Alvares L. Effects of hippocampal IP 3R inhibition on contextual fear memory consolidation, retrieval, reconsolidation and extinction. Neurobiol Learn Mem 2022; 188:107587. [PMID: 35051621 DOI: 10.1016/j.nlm.2022.107587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/03/2022] [Accepted: 01/12/2022] [Indexed: 10/19/2022]
Abstract
Intracellular calcium stores (ICS) play a dynamic role in neuronal calcium (Ca2+) homeostasis both by buffering Ca2+ excess in the cytoplasm or providing an additional source of Ca2+ when concentration increase is needed. However, in spite of the large body of evidence showing Ca2+ as an essential second messenger in many signaling cascades underlying synaptic plasticity, the direct involvement of the intracellular Ca2+-release channels (ICRCs) in memory processing has been highly overlooked. Here we investigated the role of the ICRC inositol 1,4,5-trisphosphate receptor (IP3R) activity during different memory phases using pharmacological inhibition in the dorsal hippocampus during contextual fear conditioning. We first found that post-training administration of the IP3R antagonist 2-aminoethyl diphenylborinate (2-APB) impaired memory consolidation in a dose and time-dependent manner. Inhibiting IP3Rs also disrupted memory retrieval. Contextual fear memory reconsolidation or extinction, however, were not sensitive to IP3R blockade. Taken together, our results indicate that hippocampal IP3Rs play an important role in contextual fear memory consolidation and retrieval.
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Affiliation(s)
- Henrique Schaan Fernandes
- Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, Federal University of Rio Grande do Sul, 91,501-970 Porto Alegre, Brazil; Graduate Program in Neuroscience, Institute of Health Sciences, Federal University of Rio Grande do Sul, 90,046-900 Porto Alegre, Brazil
| | - Bruno Popik
- Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, Federal University of Rio Grande do Sul, 91,501-970 Porto Alegre, Brazil; Graduate Program in Neuroscience, Institute of Health Sciences, Federal University of Rio Grande do Sul, 90,046-900 Porto Alegre, Brazil
| | - Lucas de Oliveira Alvares
- Laboratório de Neurobiologia da Memória, Biophysics Department, Biosciences Institute, Federal University of Rio Grande do Sul, 91,501-970 Porto Alegre, Brazil; Graduate Program in Neuroscience, Institute of Health Sciences, Federal University of Rio Grande do Sul, 90,046-900 Porto Alegre, Brazil.
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De-Paula VJ, Forlenza OV. Lithium modulates multiple tau kinases with distinct effects in cortical and hippocampal neurons according to concentration ranges. Naunyn Schmiedebergs Arch Pharmacol 2021; 395:105-113. [PMID: 34751792 DOI: 10.1007/s00210-021-02171-6] [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: 10/14/2020] [Accepted: 10/19/2021] [Indexed: 11/26/2022]
Abstract
The hyperphosphorylation of tau is a central mechanism in the pathogenesis of Alzheimer's disease (AD). Lithium is a potent inhibitor of glycogen synthase kinase-3beta (GSK3β), the most important tau kinase in neurons, and may also affect tau phosphorylation by modifying the expression and/or activity of other kinases, such as protein kinase A (PKA), Akt (PKB), and calcium calmodulin kinase-II (CaMKII). The aim of the present study is to determine the effect of chronic lithium treatment on the protein expression of tau and its major kinases in cortical and hippocampal neurons, at distinct working concentrations. Primary cultures of cortical and hippocampal neurons were treated with sub-therapeutic (0.02 mM and 0.2 mM) and therapeutic (2 mM) concentrations of lithium for 7 days. Protein expression of tau and tau-kinases was determined by immunoblotting. An indirect estimate of GSK3β activity was determined by the GSK3β ratio (rGSKβ). Statistically significant increments in the protein expression of tau and CaMKII were observed both in cortical and hippocampal neurons treated with subtherapeutic doses of lithium. GSK3β activity was increased in cortical, but decreased in hippocampal neurons. Distinct patterns of changes in the expression of the remaining tau tau-kinases were observed: in cortical neurons, lithium treatment was associated with consistent decrements in Akt and PKA, whereas hippocampal neurons displayed increased protein expression of Akt and decreased PKA. Our results suggest that chronic lithium treatment may yield distinct biological effects depending on the concentration range, with regional specificity. We further suggest that hippocampal neurons may be more sensitive to the effect of lithium, presenting with changes in the expression of tau-related proteins at subtherapeutic doses, which may not be mirrored by the effects observed in cortical neurons.
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Affiliation(s)
- V J De-Paula
- Laboratório de Neurociências (LIM-27), Departamento E Instituto de Psiquiatria, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
- Laboratório de Psicobiologia (LIM-23), Instituto de Psiquiatria, Hospital das Clinicas da Faculdade de Medicina da USP, Rua Dr. Ovídio Pires de Campos 785, São Paulo, SP, 05403-903, Brazil.
| | - O V Forlenza
- Laboratório de Neurociências (LIM-27), Departamento E Instituto de Psiquiatria, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
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Patel H, Zamani R. The role of PKMζ in the maintenance of long-term memory: a review. Rev Neurosci 2021; 32:481-494. [PMID: 33550786 DOI: 10.1515/revneuro-2020-0105] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/27/2020] [Indexed: 11/15/2022]
Abstract
Long-term memories are thought to be stored in neurones and synapses that undergo physical changes, such as long-term potentiation (LTP), and these changes can be maintained for long periods of time. A candidate enzyme for the maintenance of LTP is protein kinase M zeta (PKMζ), a constitutively active protein kinase C isoform that is elevated during LTP and long-term memory maintenance. This paper reviews the evidence and controversies surrounding the role of PKMζ in the maintenance of long-term memory. PKMζ maintains synaptic potentiation by preventing AMPA receptor endocytosis and promoting stabilisation of dendritic spine growth. Inhibition of PKMζ, with zeta-inhibitory peptide (ZIP), can reverse LTP and impair established long-term memories. However, a deficit of memory retrieval cannot be ruled out. Furthermore, ZIP, and in high enough doses the control peptide scrambled ZIP, was recently shown to be neurotoxic, which may explain some of the effects of ZIP on memory impairment. PKMζ knockout mice show normal learning and memory. However, this is likely due to compensation by protein-kinase C iota/lambda (PKCι/λ), which is normally responsible for induction of LTP. It is not clear how, or if, this compensatory mechanism is activated under normal conditions. Future research should utilise inducible PKMζ knockdown in adult rodents to investigate whether PKMζ maintains memory in specific parts of the brain, or if it represents a global memory maintenance molecule. These insights may inform future therapeutic targets for disorders of memory loss.
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Affiliation(s)
- Hamish Patel
- University of Exeter Medical School, Exeter, EX1 2LU, UK
| | - Reza Zamani
- University of Exeter Medical School, Exeter, EX1 2LU, UK
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Clocking In Time to Gate Memory Processes: The Circadian Clock Is Part of the Ins and Outs of Memory. Neural Plast 2018; 2018:6238989. [PMID: 29849561 PMCID: PMC5925033 DOI: 10.1155/2018/6238989] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/22/2018] [Accepted: 02/05/2018] [Indexed: 01/11/2023] Open
Abstract
Learning, memory consolidation, and retrieval are processes known to be modulated by the circadian (circa: about; dies: day) system. The circadian regulation of memory performance is evolutionarily conserved, independent of the type and complexity of the learning paradigm tested, and not specific to crepuscular, nocturnal, or diurnal organisms. In mammals, long-term memory (LTM) formation is tightly coupled to de novo gene expression of plasticity-related proteins and posttranslational modifications and relies on intact cAMP/protein kinase A (PKA)/protein kinase C (PKC)/mitogen-activated protein kinase (MAPK)/cyclic adenosine monophosphate response element-binding protein (CREB) signaling. These memory-essential signaling components cycle rhythmically in the hippocampus across the day and night and are clearly molded by an intricate interplay between the circadian system and memory. Important components of the circadian timing mechanism and its plasticity are members of the Period clock gene family (Per1, Per2). Interestingly, Per1 is rhythmically expressed in mouse hippocampus. Observations suggest important and largely unexplored roles of the clock gene protein PER1 in synaptic plasticity and in the daytime-dependent modulation of learning and memory. Here, we review the latest findings on the role of the clock gene Period 1 (Per1) as a candidate molecular and mechanistic blueprint for gating the daytime dependency of memory processing.
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Chen SQ, Wang ZS, Ma YX, Zhang W, Lu JL, Liang YR, Zheng XQ. Neuroprotective Effects and Mechanisms of Tea Bioactive Components in Neurodegenerative Diseases. Molecules 2018; 23:E512. [PMID: 29495349 PMCID: PMC6017384 DOI: 10.3390/molecules23030512] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 12/19/2022] Open
Abstract
As the population ages, neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD) impose a heavy burden on society and families. The pathogeneses of PD and AD are complex. There are no radical cures for the diseases, and existing therapeutic agents for PD and AD have diverse side effects. Tea contains many bioactive components such as polyphenols, theanine, caffeine, and theaflavins. Some investigations of epidemiology have demonstrated that drinking tea can decrease the risk of PD and AD. Tea polyphenols can lower the morbidity of PD and AD by reducing oxidative stress and regulating signaling pathways and metal chelation. Theanine can inhibit the glutamate receptors and regulate the extracellular concentration of glutamine, presenting neuroprotective effects. Additionally, the neuroprotective mechanisms of caffeine and theaflavins may contribute to the ability to antagonize the adenosine receptor A2AR and the antioxidant properties, respectively. Thus, tea bioactive components might be useful for neuronal degeneration treatment in the future. In the present paper, the neuro protection and the mechanisms of tea and its bioactive components are reviewed. Moreover, the potential challenges and future work are also discussed.
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Affiliation(s)
- Shu-Qing Chen
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Ze-Shi Wang
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Yi-Xiao Ma
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Wei Zhang
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Jian-Liang Lu
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Yue-Rong Liang
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Xin-Qiang Zheng
- Tea Research Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
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Hippocampal expression of a virus-derived protein impairs memory in mice. Proc Natl Acad Sci U S A 2018; 115:1611-1616. [PMID: 29378968 DOI: 10.1073/pnas.1711977115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The analysis of the biology of neurotropic viruses, notably of their interference with cellular signaling, provides a useful tool to get further insight into the role of specific pathways in the control of behavioral functions. Here, we exploited the natural property of a viral protein identified as a major effector of behavioral disorders during infection. We used the phosphoprotein (P) of Borna disease virus, which acts as a decoy substrate for protein kinase C (PKC) when expressed in neurons and disrupts synaptic plasticity. By a lentiviral-based strategy, we directed the singled-out expression of P in the dentate gyrus of the hippocampus and we examined its impact on mouse behavior. Mice expressing the P protein displayed increased anxiety and impaired long-term memory in contextual and spatial memory tasks. Interestingly, these effects were dependent on P protein phosphorylation by PKC, as expression of a mutant form of P devoid of its PKC phosphorylation sites had no effect on these behaviors. We also revealed features of behavioral impairment induced by P protein expression but that were independent of its phosphorylation by PKC. Altogether, our findings provide insight into the behavioral correlates of viral infection, as well as into the impact of virus-mediated alterations of the PKC pathway on behavioral functions.
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Zhao X, Liu F, Jin H, Li R, Wang Y, Zhang W, Wang H, Chen W. Involvement of PKCα and ERK1/2 signaling pathways in EGCG's protection against stress-induced neural injuries in Wistar rats. Neuroscience 2017; 346:226-237. [PMID: 28131624 DOI: 10.1016/j.neuroscience.2017.01.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/12/2017] [Accepted: 01/14/2017] [Indexed: 02/08/2023]
Abstract
Stress-induced neural injuries are closely linked to the pathogenesis of various neuropsychiatric disorders and psychosomatic diseases. We and others have previously demonstrated certain protective effects of epigallocatechin-3-gallate (EGCG) in stress-induced cerebral impairments, but the underlying protective mechanisms still remain poorly elucidated. Here we provide evidence to support the possible involvement of PKCα and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways in EGCG-mediated protection against restraint stress-induced neural injuries in rats. In both open-field and step-through behavioral tests, the restraint stress-induced neuronal impairments were significantly ameliorated by administration of EGCG or green tea polyphenols (GTPs), which was associated with a partial restoration of normal plasma glucocorticoid, dopamine and serotonin levels. Furthermore, the stress-induced decrease of PKCα and ERK1/2 expression and phosphorylation was significantly attenuated by EGCG and to a less extent by GTP administration. Additionally, EGCG supplementation restored the production of adenosine triphosphate (ATP) and the expression of a key regulator of cellular energy metabolism, the peroxisome proliferators-activated receptor-γ coactivator-1α (PGC-1α), in stressed animals. In conclusion, PKCα and ERK1/2 signaling pathways as well as PGC-1α-mediated ATP production might be involved in EGCG-mediated protection against stress-induced neural injuries.
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Affiliation(s)
- Xiaoling Zhao
- Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Fengqin Liu
- Weifang People's Hospital, Weifang, Shandong Province, China
| | - Haimin Jin
- Tianjin Institute of Health and Environmental Medicine, Tianjin, China; Tianjin Medical University, Tianjin, China
| | - Renjia Li
- Tianjin Institute of Health and Environmental Medicine, Tianjin, China; Tianjin Medical University, Tianjin, China
| | - Yonghui Wang
- Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | | | - Haichao Wang
- The Feinstein Institute for Medical Research, Manhasset, NY, USA; Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY, USA.
| | - Weiqiang Chen
- Tianjin Institute of Health and Environmental Medicine, Tianjin, China; The Feinstein Institute for Medical Research, Manhasset, NY, USA.
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Jurkus R, Day HLL, Guimarães FS, Lee JLC, Bertoglio LJ, Stevenson CW. Cannabidiol Regulation of Learned Fear: Implications for Treating Anxiety-Related Disorders. Front Pharmacol 2016; 7:454. [PMID: 27932983 PMCID: PMC5121237 DOI: 10.3389/fphar.2016.00454] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/11/2016] [Indexed: 01/04/2023] Open
Abstract
Anxiety and trauma-related disorders are psychiatric diseases with a lifetime prevalence of up to 25%. Phobias and post-traumatic stress disorder (PTSD) are characterized by abnormal and persistent memories of fear-related contexts and cues. The effects of psychological treatments such as exposure therapy are often only temporary and medications can be ineffective and have adverse side effects. Growing evidence from human and animal studies indicates that cannabidiol, the main non-psychotomimetic phytocannabinoid present in Cannabis sativa, alleviates anxiety in paradigms assessing innate fear. More recently, the effects of cannabidiol on learned fear have been investigated in preclinical studies with translational relevance for phobias and PTSD. Here we review the findings from these studies, with an emphasis on cannabidiol regulation of contextual fear. The evidence indicates that cannabidiol reduces learned fear in different ways: (1) cannabidiol decreases fear expression acutely, (2) cannabidiol disrupts memory reconsolidation, leading to sustained fear attenuation upon memory retrieval, and (3) cannabidiol enhances extinction, the psychological process by which exposure therapy inhibits learned fear. We also present novel data on cannabidiol regulation of learned fear related to explicit cues, which indicates that auditory fear expression is also reduced acutely by cannabidiol. We conclude by outlining future directions for research to elucidate the neural circuit, psychological, cellular, and molecular mechanisms underlying the regulation of fear memory processing by cannabidiol. This line of investigation may lead to the development of cannabidiol as a novel therapeutic approach for treating anxiety and trauma-related disorders such as phobias and PTSD in the future.
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Affiliation(s)
- Regimantas Jurkus
- School of Mathematical Sciences, University of Nottingham University Park, Nottingham, UK
| | - Harriet L L Day
- School of Biosciences, University of Nottingham Loughborough, UK
| | | | | | - Leandro J Bertoglio
- Department of Pharmacology, Federal University of Santa Catarina Florianopolis, Brazil
| | - Carl W Stevenson
- School of Biosciences, University of Nottingham Loughborough, UK
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Singh NA, Mandal AKA, Khan ZA. Potential neuroprotective properties of epigallocatechin-3-gallate (EGCG). Nutr J 2016; 15:60. [PMID: 27268025 PMCID: PMC4897892 DOI: 10.1186/s12937-016-0179-4] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/02/2016] [Indexed: 12/17/2022] Open
Abstract
Neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) enforce an overwhelming social and economic burden on society. They are primarily characterized through the accumulation of modified proteins, which further trigger biological responses such as inflammation, oxidative stress, excitotoxicity and modulation of signalling pathways. In a hope for cure, these diseases have been studied extensively over the last decade to successfully develop symptom-oriented therapies. However, so far no definite cure has been found. Therefore, there is a need to identify a class of drug capable of reversing neural damage and preventing further neural death. This review therefore assesses the reliability of the neuroprotective benefits of epigallocatechin-gallate (EGCG) by shedding light on their biological, pharmacological, antioxidant and metal chelation properties, with emphasis on their ability to invoke a range of cellular mechanisms in the brain. It also discusses the possible use of nanotechnology to enhance the neuroprotective benefits of EGCG.
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Affiliation(s)
- Neha Atulkumar Singh
- Department of Integrative Biology, School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Abul Kalam Azad Mandal
- Department of Biotechnology, School of Biosciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Zaved Ahmed Khan
- Centre for Interdisciplinary Biomedical Research, Adesh University, Bathinda, Punjab, India.
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Wang Y, Wang YX, Liu T, Law PY, Loh HH, Qiu Y, Chen HZ. μ-Opioid receptor attenuates Aβ oligomers-induced neurotoxicity through mTOR signaling. CNS Neurosci Ther 2014; 21:8-14. [PMID: 25146548 DOI: 10.1111/cns.12316] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 12/19/2022] Open
Abstract
AIMS μ-opioid receptor (OPRM1) exerts many functions such as antinociception, neuroprotection, and hippocampal plasticity. A body of evidence has shown that OPRM1 activation could stimulate downstream effectors of mechanistic/mammalian target of rapamycin (mTOR). However, it is not clear whether OPRM1 protects neurons against β-amyloid peptide (Aβ) neurotoxicity through mTOR signaling. METHODS The effects of OPRM1 activation on Aβ oligomers-induced neurotoxicity were assessed by cell viability and neurite outgrowth assay in primary cultured cortical neurons. The activities of mTOR, protein kinase B (Akt) and p70 ribosomal S6 kinase (p70 S6k) upon OPRM1 activation by morphine were measured by immunoblotting their phosphorylation status. RESULTS Morphine dose-dependently attenuated Aβ oligomers-induced neurotoxicity. Aβ oligomers downregulated mTOR signaling. Morphine significantly rescued mTOR signaling by reversal of Aβ oligomers' effect on mTOR and its upstream signaling molecule Akt, as well as its downstream molecule p70 S6k. Moreover, the neuroprotective effect of morphine could be reversed by OPRM1 selective antagonist and phosphatidylinositol 3-kinases (PI3K), Akt and mTOR inhibitors. Furthermore, endogenous opioids-enkaphalins also attenuated Aβ oligomers-induced neurotoxicity. CONCLUSIONS Our findings demonstrated OPRM1 activation attenuated Aβ oligomers-induced neurotoxicity through mTOR signaling. It may provide new insight into the pathological process and useful strategy for therapeutic interventions against Aβ neurotoxicity.
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Affiliation(s)
- Yan Wang
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Caceres LG, Cid MP, Uran SL, Zorrilla Zubilete MA, Salvatierra NA, Guelman LR. Pharmacological alterations that could underlie radiation-induced changes in associative memory and anxiety. Pharmacol Biochem Behav 2013; 111:37-43. [PMID: 23958578 DOI: 10.1016/j.pbb.2013.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 08/02/2013] [Accepted: 08/08/2013] [Indexed: 11/30/2022]
Abstract
It is widely known that ionizing radiation is a physical agent broadly used to kill tumor cells during human cancer therapy. Unfortunately, adjacent normal tissues can concurrently undergo undesirable cell injury. Previous data of our laboratory demonstrated that exposure of developing rats to ionizing radiations induced a variety of behavioral differences respect to controls, including changes in associative memory and in anxiety state. However, there is a lack of data concerning modifications in different related pharmacological intermediaries. Therefore, the aim of the present study was to investigate whether the behavioral differences observed in young animals irradiated at birth might be underlain by early changes in PKCß1 levels which, in turn, could lead to changes in hippocampal GABAergic neurotransmission. Male Wistar rats were irradiated with 5Gy of X rays between 24 and 48 h after birth. Different pharmacological markers related to the affected behavioral tasks were assessed in control and irradiated hippocampus at 15 and 30 days, namely GABAA receptor, GAD65-67, ROS and PKCß1. Results showed that all measured parameters were increased in the hippocampus of 30-days-old irradiated animals. In contrast, in the hippocampus of 15-days-old irradiated animals only the levels of PKCß1 were decreased. These data suggest that PKCß1 might constitute a primary target for neonatal radiation damage on the hippocampus. Therefore, it could be hypothesized that an initial decrease in the levels of this protein can trigger a subsequent compensatory increase that, in turn, could be responsible for the plethora of biochemical changes that might underlie the previously observed behavioral alterations.
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Affiliation(s)
- L G Caceres
- 1ª Cátedra de Farmacología, Facultad de Medicina, UBA-CEFyBO-CONICET, Paraguay 2155, piso 15, (1121) Buenos Aires, Argentina
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Abrial E, Etievant A, Bétry C, Scarna H, Lucas G, Haddjeri N, Lambás-Señas L. Protein kinase C regulates mood-related behaviors and adult hippocampal cell proliferation in rats. Prog Neuropsychopharmacol Biol Psychiatry 2013; 43:40-8. [PMID: 23228462 DOI: 10.1016/j.pnpbp.2012.11.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/08/2012] [Accepted: 11/18/2012] [Indexed: 12/16/2022]
Abstract
The neurobiological mechanisms underlying the pathophysiology and therapeutics of bipolar disorder are still unknown. In recent years, protein kinase C (PKC) has emerged as a potential key player in mania. To further investigate the role of this signaling system in mood regulation, we examined the effects of PKC modulators in behavioral tests modeling several facets of bipolar disorder and in adult hippocampal cell proliferation in rats. Our results showed that a single injection of the PKC inhibitors tamoxifen (80 mg/kg, i.p.) and chelerythrine (3 mg/kg, s.c.) attenuated amphetamine-induced hyperlocomotion and decreased risk-taking behavior, supporting the efficacy of PKC blockade in acute mania. Moreover, chronic exposure to tamoxifen (10 mg/kg/day, i.p., for 14 days) or chelerythrine (0.3 mg/kg/day, s.c., for 14 days) caused depressive-like behavior in the forced swim test, and resulted in a reduction of cell proliferation in the dentate gyrus of the hippocampus. Finally, we showed that, contrary to the PKC inhibitors, the PKC activator phorbol 12-myristate 13-acetate (PMA) enhanced risk-taking behavior and induced an antidepressant-like effect. Taken together, these findings support the involvement of PKC in regulating opposite facets of bipolar disorder, and emphasize a major role for PKC in this disease.
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Guerra GP, Mello CF, Bochi GV, Pazini AM, Rosa MM, Ferreira J, Rubin MA. Spermidine-induced improvement of memory involves a cross-talk between protein kinases C and A. J Neurochem 2012; 122:363-73. [DOI: 10.1111/j.1471-4159.2012.07778.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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16
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Pozzi L, Sacchetti G, Agnoli L, Mainolfi P, Invernizzi RW, Carli M. Distinct Changes in CREB Phosphorylation in Frontal Cortex and Striatum During Contingent and Non-Contingent Performance of a Visual Attention Task. Front Behav Neurosci 2011; 5:65. [PMID: 22016726 PMCID: PMC3191343 DOI: 10.3389/fnbeh.2011.00065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Accepted: 09/21/2011] [Indexed: 01/26/2023] Open
Abstract
The cyclic-adenosine monophosphate response element-binding protein (CREB) family of transcription factors has been implicated in numerous forms of behavioral plasticity. We investigated CREB phosphorylation along some nodes of corticostriatal circuitry such as frontal cortex (FC) and dorsal (caudate-putamen, CPu) and ventral (nucleus accumbens, NAC) striatum in response to the contingent or non-contingent performance of the five-choice serial reaction time task (5-CSRTT) used to assess visuospatial attention. Three experimental manipulations were used; an attentional performance group (contingent, "master"), a group trained previously on the task but for whom the instrumental contingency coupling responding with stimulus detection and reward was abolished (non-contingent, "yoked") and a control group matched for food deprivation and exposure to the test apparatus (untrained). Rats trained on the 5-CSRTT (both master and yoked) had higher levels of CREB protein in the FC, CPu, and NAC compared to untrained controls. Despite the divergent behavior of "master" and "yoked" rats CREB activity in the FC was not substantially different. In rats performing the 5-CSRTT ("master"), CREB activity was completely abolished in the CPu whereas in the NAC it remained unchanged. In contrast, CREB phosphorylation in CPu and NAC increased only when the contingency changed from goal-dependent to goal-independent reinforcement ("yoked"). The present results indicate that up-regulation of CREB protein expression across cortical and striatal regions possibly reflects the extensive instrumental learning and performance whereas increased CREB activity in striatal regions may signal the unexpected change in the relationship between instrumental action and reinforcement.
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Affiliation(s)
- Laura Pozzi
- Laboratory of Neurochemistry and Behaviour, Department of Neuroscience, Institute for Pharmacological Research "Mario Negri" Milano, Italy
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17
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Abstract
This review focuses on recent developments in the use of natural products as therapeutics for Alzheimer's disease. The compounds span a diverse array of structural classes and are organized according to their mechanism of action, with the focus primarily on the major hypotheses. Overall, the review discusses more than 180 compounds and summarizes 400 references.
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Affiliation(s)
- Philip Williams
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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18
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Effect of ketamine administration on memory consolidation, p-CREB and c-fos expression in the hippocampal slices of minor rats. Mol Biol Rep 2010; 38:2401-7. [PMID: 21080080 DOI: 10.1007/s11033-010-0374-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
Abstract
To investigate the effect of ketamine administration on memory consolidation, p-CREB and c-fos expression in hippocampus of infant rats and the possible mechanism. Ninety-six SD rats of 21 days old were divided into seven groups, Y-maze was used to test the ability of learning and memory for minor rats. p-CREB and c-fos protein expression was tested by immunhistochemistry. The results showed that the memory consolidation rate in normal saline group mice was higher than that in k1a and k7a group (P<0.05). However, normal saline group between k1b and k7b group was not significant difference. The p-CREB and c-fos protein expressing cells of normal saline group were higher than those in passive control group, pseudotraining group, k1a and k7a group (P<0.05). However, there was not significant difference between normal saline group and k1b or k7b group. The c-fos protein expressing cells of pseudotraining group was higher than those in passive control group, however, the p-CREB protein expressing cells was not significant difference. Therefore, administration of ketamine may temporally affect the ability of memory consolidation rate of minor rats through suppressing the expression of p-CREB and c-fos protein in hippocampus.
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19
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Mandel SA, Amit T, Weinreb O, Reznichenko L, Youdim MBH. Simultaneous manipulation of multiple brain targets by green tea catechins: a potential neuroprotective strategy for Alzheimer and Parkinson diseases. CNS Neurosci Ther 2009; 14:352-65. [PMID: 19040558 DOI: 10.1111/j.1755-5949.2008.00060.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Current therapeutic approaches for Alzheimer and Parkinson disease (AD and PD, respectively) are merely symptomatic, intended for the treatment of symptoms, but offer only partial benefit, without any disease-modifying activity. Novel promising strategies suggest the use of antiinflammatory drugs, antioxidants, iron-complexing molecules, neurotrophic factor delivery, inhibitors of the amyloid precursor protein (APP)-processing secretases, gamma and beta (that generate the amyloid-beta peptides, Abeta), anti-Abeta aggregation molecules, the interference with lipid cholesterol metabolism and naturally occurring plant flavonoids to potentially reverse the course of the diseases. Human epidemiological and new animal data suggest that tea drinking may decrease the incidence of dementia, AD, and PD. In particular, its main catechin polyphenol constituent (-)-epigallocatechin-3-gallate (EGCG) has been shown to exert neuroprotective/neurorescue activities in a wide array of cellular and animal models of neurological disorders. In the current article, we review the literature on the impact of the multimodal activities of green tea polyphenols and their neuroprotective effect on AD and PD.
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Affiliation(s)
- Silvia A Mandel
- Eve Topf Center for Neurodegenerative Diseases Research and Department of Pharmacology, Faculty of Medicine, Technion, Haifa, Israel.
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20
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Schaeffer EL, Zorrón Pu L, Gagliotti DAM, Gattaz WF. Conditioning training and retrieval increase phospholipase A(2) activity in the cerebral cortex of rats. J Neural Transm (Vienna) 2008; 116:41-50. [PMID: 18982240 DOI: 10.1007/s00702-008-0133-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 10/04/2008] [Indexed: 12/25/2022]
Abstract
In rats, phospholipase A(2) (PLA(2)) activity was found to be increased in the hippocampus immediately after training and retrieval of a contextual fear conditioning paradigm (step-down inhibitory avoidance [IA] task). In the present study we investigated whether PLA(2) is also activated in the cerebral cortex of rats in association with contextual fear learning and retrieval. We observed that IA training induces a rapid (immediately after training) and long-lasting (3 h after training) activation of PLA(2) in both frontal and parietal cortices. However, immediately after retrieval (measured 24 h after training), PLA(2) activity was increased just in the parietal cortex. These findings suggest that PLA(2) activity is differentially required in the frontal and parietal cortices for the mechanisms of contextual learning and retrieval. Because reduced brain PLA(2) activity has been reported in Alzheimer disease, our results suggest that stimulation of PLA(2) activity may offer new treatment strategies for this disease.
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Affiliation(s)
- E L Schaeffer
- Department and Institute of Psychiatry, University of São Paulo, Rua Doutor Ovídio Pires de Campos, São Paulo, SP, Brazil.
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21
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Isosaka T, Hattori K, Kida S, Kohno T, Nakazawa T, Yamamoto T, Yagi T, Yuasa S. Activation of Fyn tyrosine kinase in the mouse dorsal hippocampus is essential for contextual fear conditioning. Eur J Neurosci 2008; 28:973-81. [PMID: 18691323 DOI: 10.1111/j.1460-9568.2008.06405.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fyn-tyrosine-kinase-deficient mice exhibit defects in the Morris water maze test and long-term potentiation (LTP) induction in the hippocampus, and given that LTP has been postulated as the neural basis for memory formation, Fyn may be required for hippocampus-dependent memory formation. However, how Fyn is involved in the process of memory formation is unclear. To investigate the role of Fyn in hippocampal memory formation, we first tested the behavior of Fyn-deficient mice by contextual fear conditioning. A mouse was placed in a context and a foot shock was delivered, so that the mouse associated the context with the shock. We found that the freezing response of Fyn-deficient mice to the context was impaired at 24 h after conditioning. We then measured freezing at 1 h after conditioning, and found that their short-term contextual fear memory was also impaired. We used Western blotting to examine the mode of Fyn activation in dorsal hippocampal tissue following contextual fear conditioning. Fyn activation peaked as early as 5-10 min after contextual fear conditioning and persisted for at least 40 min. Concomitant increases in tyrosine phosphorylation of several proteins, including NR2B, were also observed, but no increases in tyrosine phosphorylation were observed in Fyn-deficient mice. Thus, both short-term and long-term (24-h) contextual fear memory were impaired in Fyn-deficient mice, and Fyn activation in the dorsal hippocampus transiently increased after contextual fear conditioning. These findings strongly suggest that activation of the Fyn signaling pathway is involved in hippocampus-dependent formation of contextual fear memory.
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Affiliation(s)
- Tomoko Isosaka
- Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
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22
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Mandel SA, Amit T, Kalfon L, Reznichenko L, Youdim MBH. Targeting multiple neurodegenerative diseases etiologies with multimodal-acting green tea catechins. J Nutr 2008; 138:1578S-1583S. [PMID: 18641210 DOI: 10.1093/jn/138.8.1578s] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Green tea is currently considered a source of dietary constituents endowed with biological and pharmacological activities relevant to human health. Human epidemiological and new animal data suggest that the pharmacological benefits of tea drinking may help to protect the brain as we age. Indeed, tea consumption is inversely correlated with the incidence of dementia and Alzheimer's and Parkinson's diseases. In particular, its main catechin polyphenol constituent (-)-epigallocatechin-3-gallate has been shown to exert neuroprotective/neurorescue activities in a wide array of cellular and animal models of neurological disorders. The intense efforts dedicated in recent years to shed light on the molecular mechanisms participating in the brain protective action of green tea indicate that in addition to the known antioxidant activity of catechins, the modulation of signal transduction pathways, cell survival/death genes, and mitochondrial function all contribute significantly to the induction of neuron viability. Because of the multietiological character of neurodegenerative disease pathology, these natural compounds are receiving significant attention as therapeutic cytoprotective agents that simultaneously manipulate multiple desired targets in the central nervous system. This article elaborates on the multimodal activities of green tea polyphenols with emphasis on their recently described neurorescue/neuroregenerative and mitochondrial stabilization actions.
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Affiliation(s)
- Silvia A Mandel
- Eve Topf Center for Neurodegenerative Diseases Research and Department of Pharmacology, Faculty of Medicine, Technion, Haifa, Israel.
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23
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Qi XL, Zhu B, Zhang XH, Li BM. Are beta-adrenergic receptors in the hippocampal CA1 region required for retrieval of contextual fear memory? Biochem Biophys Res Commun 2008; 368:186-91. [PMID: 18190786 DOI: 10.1016/j.bbrc.2008.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 01/03/2008] [Indexed: 10/22/2022]
Abstract
It is well established that beta-adrenoceptors (beta-ARs) in the hippocampal CA1 region are involved in regulating synaptic plasticity and are essential for acquisition and consolidation of spatial memory and contextual fear memory. Previous studies reported that beta-ARs in the CA1 region are also involved in memory retrieval. The present study re-examined the role of hippocampal beta-ARs in retrieval of conditioned contextual fear. We bilaterally infused a high dose of the beta-AR antagonist propranolol (15mug in 1mul saline) into the CA1 region 30min before retention test and found that propranolol produced no deficit in retrieval of either 1-day or 7-day contextual fear. We then examined if beta-AR stimulation would produce a beneficial effect. The beta-AR agonist isoproterenol (10mug in 1mul saline) was infused into the CA1 region 30min before retention test. Surprisingly, isoproterenol did not enhance but severely disrupted retrieval of 7-day contextual fear memory, with no impact on retrieval of 1-day contextual fear memory. The present study argues against the previous conclusion that beta-ARs in the CA1 region play a role in memory retrieval. beta-ARs in the CA1 region may be dispensable for retrieval of conditioned contextual fear.
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Affiliation(s)
- Xue-Lian Qi
- Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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24
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Abstract
The present study was undertaken to investigate the beneficial effects of Atorvastatin and Simvastatin in cognitive dysfunctions of rats. Alprazolam, Scopolamine and high fat diet (HFD) induced amnesia served as interoceptive memory models where as, Water-maze and Elevated plus-maze served as exteroceptive models. A total of 38 groups of rats were used in this investigation. Escape latency time (ELT) recorded during acquisition trials conducted from day 1 to day 4, in water maze was taken as an index of acquisition, where as mean time spent in target quadrant during retrieval trial on day 5, was taken as the index of retrieval (memory). On elevated plus-maze, transfer latency (TL) measured on 1st d served as the index of acquisition and TL recorded on 2nd d was taken as the index of retrieval (memory). Alprazolam (0.5 mg kg(-1) intraperitoneally), Scopolamine (0.4 mg kg(-1) intraperitoneally) and HFD treated (for 90 days) rats exhibited amnesia as reflected by impairment in learning ability as well as memory, when tested on both, water maze and elevated plus maze. Atorvastatin (5 mg kg(-1) orally) as well as Simvastatin (5 mg kg(-1) orally) significantly attenuated Alprazolam, Scopolamine and HFD induced amnesia. These results highlight the ameliorative role of statins in experimental amnesia with possible involvement of their cholesterol dependent as well as cholesterol independent actions.
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Affiliation(s)
- Milind Parle
- Pharmacology Division, Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, India.
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25
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Igaz LM, Winograd M, Cammarota M, Izquierdo LA, Alonso M, Izquierdo I, Medina JH. Early activation of extracellular signal-regulated kinase signaling pathway in the hippocampus is required for short-term memory formation of a fear-motivated learning. Cell Mol Neurobiol 2007; 26:989-1002. [PMID: 16977492 DOI: 10.1007/s10571-006-9116-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1. According to its duration there are, at least, two major forms of memory in mammals: short term memory (STM) which develops in a few seconds and lasts several hours and long-term memory (LTM) lasting days, weeks and even a lifetime. In contrast to LTM, very little is known about the neural, cellular and molecular requirements for mammalian STM formation. 2. Here we show that early activation of extracellular signal-regulated kinases 1/2 (ERK1/2) in the hippocampus is required for the establishment of STM for a one-trial inhibitory avoidance task in the rat. Immediate posttraining infusion of U0126 (a selective inhibitor of ERK kinase) into the CA1 region of the dorsal hippocampus blocked STM formation. 3. Reversible inactivation of the entorhinal cortex through muscimol infusion produced deficits in STM and a selective and rapid decrease in hippocampal ERK2 activation.4. Together with our previous findings showing a rapid decrease in ERK2 activation and impaired STM after blocking BDNF function, the present results strongly suggest that ERK2 signaling in the hippocampus is a critical step in STM processing.
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Affiliation(s)
- Lionel Müller Igaz
- Instituto de Biología Celular y Neurociencias, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 3, 1121, Buenos Aires, Argentina
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26
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Alkon DL, Sun MK, Nelson TJ. PKC signaling deficits: a mechanistic hypothesis for the origins of Alzheimer's disease. Trends Pharmacol Sci 2007; 28:51-60. [PMID: 17218018 DOI: 10.1016/j.tips.2006.12.002] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 11/06/2006] [Accepted: 12/19/2006] [Indexed: 11/29/2022]
Abstract
There is strong evidence that protein kinase C (PKC) isozyme signaling pathways are causally involved in associative memory storage. Other observations have indicated that PKC signaling pathways regulate important molecular events in the neurodegenerative pathophysiology of Alzheimer's disease (AD), which is a progressive dementia that is characterized by loss of recent memory. This parallel involvement of PKC signaling in both memory and neurodegeneration indicates a common basis for the origins of both the symptoms and the pathology of AD. Here, we discuss this conceptual framework as a basis for an autopsy-validated peripheral biomarker--and for AD drug design targeting drugs (bryostatin and bryologs) that activate PKC isozymes--that has already demonstrated significant promise for treating both AD neurodegeneration and its symptomatic memory loss.
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Affiliation(s)
- Daniel L Alkon
- Blanchette Rockefeller Neurosciences Institute, 9601 Medical Center Drive, Rockville, MD 20850, USA.
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27
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Tramontina F, Tramontina AC, Souza DF, Leite MC, Gottfried C, Souza DO, Wofchuk ST, Gonçalves CA. Glutamate uptake is stimulated by extracellular S100B in hippocampal astrocytes. Cell Mol Neurobiol 2006; 26:81-6. [PMID: 16633903 DOI: 10.1007/s10571-006-9099-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 10/14/2005] [Indexed: 01/21/2023]
Abstract
1.S100B is a calcium-binding protein expressed and secreted by astrocytes, which has been implicated in glial-neuronal communication. Extracellular S100B appears to protect hippocampal neurons against toxic concentrations of glutamate. Here we investigated a possible autocrine role of S100B in glutamate uptake activity. 2. Astrocyte cultures were prepared of hippocampi from neonate Wistar rats. [(3)H] Glutamate uptake was measured after addition of S100B protein, antibody anti-S100B or TRTK-12, a peptide that blocks S100B activity mediated by the C-terminal region. 3.Antibody anti-S100B addition decreased glutamate uptake measured 30 min after medium replacement, without affecting cell integrity or viability. Moreover, low levels of S100B (less than 0.1 ng/mL) stimulated glutamate uptake measured immediately after medium replacement. 4. This finding reinforces the importance of astrocytes in the glutamatergic transmission, particularly the role of S100B neuroprotection against excitotoxic damage.
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Affiliation(s)
- Francine Tramontina
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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28
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Barker GRI, Bashir ZI, Brown MW, Warburton EC. A temporally distinct role for group I and group II metabotropic glutamate receptors in object recognition memory. Learn Mem 2006; 13:178-86. [PMID: 16585793 PMCID: PMC1409835 DOI: 10.1101/lm.77806] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Recognition memory, involving the ability to discriminate between a novel and familiar object, depends on the integrity of the perirhinal cortex (PRH). Glutamate, the main excitatory neurotransmitter in the cortex, is essential for many types of memory processes. Of the subtypes of glutamate receptor, metabotropic receptors (mGluRs) have received less study than NMDA receptors; thus, the reported experiments examined the role of mGluRs in familiarity discrimination in the rat PRH. Experiments 1 and 2 assessed the effects of systemic administration of MPEP, a group I mGluR (specifically mGluR5) antagonist, and/or LY341495, a group II mGluR antagonist, on a spontaneous object novelty preference task. Simultaneous antagonism of both group I and II mGluRs impaired familiarity discrimination following a 24-h but not a 15-min delay, while antagonism of either mGluR subtype alone had no effect at either delay. The impairment was in acquisition, as in Experiment 3 coadministration of MPEP and LY341495 did not affect recognition memory performance when administered either after the sample phase or prior to test. The impairment in long-term recognition memory was mediated by mGluRs in the PRH, as localized intracortical antagonism of group I and II mGluRs also produced a deficit (Experiment 4). No evidence was found for an involvement of group III mGluRs in the acquisition of long-term familiarity discrimination (Experiment 5). These findings establish that glutamatergic neurotransmission in the PRH via group I and II mGluRs is crucial for the acquisition, but not for the consolidation or retrieval of long-term object recognition memory.
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Affiliation(s)
- Gareth Robert Isaac Barker
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, Bristol BS8 1 TD, United Kingdom
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29
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Roesler R, Luft T, Oliveira SHS, Farias CB, Almeida VR, Quevedo J, Dal Pizzol F, Schröder N, Izquierdo I, Schwartsmann G. Molecular mechanisms mediating gastrin-releasing peptide receptor modulation of memory consolidation in the hippocampus. Neuropharmacology 2006; 51:350-7. [PMID: 16735043 DOI: 10.1016/j.neuropharm.2006.03.033] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 03/24/2006] [Accepted: 03/24/2006] [Indexed: 11/16/2022]
Abstract
Although the gastrin-releasing peptide-preferring bombesin receptor (GRPR) has been implicated in memory formation, the underlying molecular events are poorly understood. In the present study, we examined interactions between the GRPR and cellular signaling pathways in influencing memory consolidation in the hippocampus. Male Wistar rats received bilateral infusions of bombesin (BB) into the dorsal hippocampus immediately after inhibitory avoidance (IA) training. Intermediate doses of BB enhanced, whereas a higher dose impaired, 24-h IA memory retention. The BB-induced memory enhancement was prevented by pretraining infusions of a GRPR antagonist or inhibitors of protein kinase C (PKC), mitogen-activated protein kinase (MAPK) kinase and protein kinase A (PKA), but not by a neuromedin B receptor (NMBR) antagonist. We next further investigated the interactions between the GRPR and the PKA pathway. BB-induced enhancement of consolidation was potentiated by coinfusion of activators of the dopamine D1/D5 receptor (D1R)/cAMP/PKA pathway and prevented by a PKA inhibitor. We conclude that memory modulation by hippocampal GRPRs is mediated by the PKC, MAPK, and PKA pathways. Furthermore, pretraining infusion of BB prevented beta-amyloid peptide (25-35)-induced memory impairment, supporting the view that the GRPR is a target for the development of cognitive enhancers for dementia.
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Affiliation(s)
- R Roesler
- Cellular and Molecular Neuropharmacology Research Group, Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Rua Sarmento Leite, Campus Centro/UFRGS, Porto Alegre, RS, Brazil.
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30
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Kuzirian AM, Epstein HT, Gagliardi CJ, Nelson TJ, Sakakibara M, Taylor C, Scioletti AB, Alkon DL. Bryostatin enhancement of memory in Hermissenda. THE BIOLOGICAL BULLETIN 2006; 210:201-14. [PMID: 16801495 DOI: 10.2307/4134558] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bryostatin, a potent agonist of protein kinase C (PKC), when administered to Hermissenda was found to affect acquisition of an associative learning paradigm. Low bryostatin concentrations (0.1 to 0.5 ng/ml) enhanced memory acquisition, while concentrations higher than 1.0 ng/ml down-regulated the pathway and no recall of the associative training was exhibited. The extent of enhancement depended upon the conditioning regime used and the memory stage normally fostered by that regime. The effects of two training events (TEs) with paired conditioned and unconditioned stimuli, which standardly evoked only short-term memory (STM) lasting 7 min, were--when bryostatin was added concurrently--enhanced to a long-term memory (LTM) that lasted about 20 h. The effects of both 4- and 6-paired TEs (which by themselves did not generate LTM), were also enhanced by bryostatin to induce a consolidated memory (CM) that lasted at least 5 days. The standard positive 9-TE regime typically produced a CM lasting at least 6 days. Low concentrations of bryostatin (<0.5 ng/ml) elicited no demonstrable enhancement of CM from 9-TEs. However, animals exposed to bryostatin concentrations higher than 1.0 ng/ml exhibited no behavioral learning. Sharp-electrode intracellular recordings of type-B photoreceptors in the eyes from animals conditioned in vivo with bryostatin revealed changes in input resistance and an enhanced long-lasting depolarization (LLD) in response to light. Likewise, quantitative immunocytochemical measurements using an antibody specific for the PKC-activated Ca2+/GTP-binding protein calexcitin showed enhanced antibody labeling with bryostatin. Animals exposed to the PKC inhibitor bisindolylmaleimide-XI (Ro-32-0432) administered by immersion prior to 9-TE conditioning showed no training-induced changes with or without bryostatin exposure. However, if animals received bryostatin before Ro-32, the enhanced acquisition and demonstrated recall still occurred. Therefore, pathways responsible for the enhancement effects induced by bryostatin were putatively mediated by PKC. Overall, the data indicated that PKC activation occurred and calexcitin levels were raised during the acquisition phases of associative conditioning and memory initiation, and subsequently returned to baseline levels within 24 and 48 h, respectively. Therefore, the protracted recall measured by the testing regime used was probably due to bryostatin-induced changes during the acquisition and facilitated storage of memory, and not necessarily to enhanced recall of the stored memory when tested many days after training.
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Affiliation(s)
- A M Kuzirian
- Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA.
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31
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Affiliation(s)
- Mohammad R Zarrindast
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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32
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Shalin SC, Egli R, Birnbaum SG, Roth TL, Levenson JM, Sweatt JD. Signal transduction mechanisms in memory disorders. PROGRESS IN BRAIN RESEARCH 2006; 157:25-41. [PMID: 17167902 DOI: 10.1016/s0079-6123(06)57003-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This chapter explores some of the molecular events contributing to memory formation and how, when these events malfunction, disturbances in memory occur. After a brief discussion of signaling in the hippocampus, we will explore the topics of human mental retardation syndromes that involve disruption of these processes, including Angelman syndrome (AS), Neurofibromatosis 1 (NF1)-associated learning disorders, Coffin-Lowry syndrome (CLS), Rubinstein-Taybi syndrome (RTS), and Rett syndrome (RTT).
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Affiliation(s)
- Sara C Shalin
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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33
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Cammarota M, Bevilaqua LRM, Barros DM, Vianna MRM, Izquierdo LA, Medina JH, Izquierdo I. Retrieval and the extinction of memory. Cell Mol Neurobiol 2005; 25:465-74. [PMID: 16075375 DOI: 10.1007/s10571-005-4009-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Accepted: 08/03/2004] [Indexed: 11/28/2022]
Abstract
1. Memory is assessed by measuring retrieval which is often elicited by the solely presentation of the conditioned stimulus (CS). However, as known since Pavlov, presentation of the CS alone generates extinction. 2. One-trial avoidance (IA) is a much used conditioned fear paradigm in which the CS is the safe part of a training apparatus, the unconditioned stimulus (US) is a footshock and the conditioned response (CR) is to stay in the safe area. Retrieval of the memory for the step-down version of this task is measured in the absence of the US, as latency to step-down from the safe area (i.e., a platform). 3. Extinction of the IA response is installed at the moment of the first non-reinforced test session, as clearly shown by the fact that many drugs, including PKA, ERK and protein synthesis inhibitors as well as NMDA receptor antagonists, hinder extinction when infused into the hippocampus or the basolateral amygdala at the moment of the first test session but not later. 4. Some, but not all the molecular systems required for extinction are also activated by retrieval, further endorsing the hypothesis that although retrieval is necessary for the generation of extinction this last process constitutes a new learning secondary to the non-reinforced expression of the original trace.
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Affiliation(s)
- Martín Cammarota
- Centro de Memória, IPB, Pontificia Universidade Católica do Rio Grande do Sul (PUCRS), Av. Ipiranga 6690-2. Andar, 90610-000, Porto Alegre, RS, Brazil
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Schaeffer EL, Gattaz WF. Inhibition of calcium-independent phospholipase A2 activity in rat hippocampus impairs acquisition of short- and long-term memory. Psychopharmacology (Berl) 2005; 181:392-400. [PMID: 15830227 DOI: 10.1007/s00213-005-2256-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 02/14/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Phospholipase A(2) (PLA(2)) is a family of enzymes that cleave membrane phospholipids generating important lipid mediators in signal transduction. In rat hippocampal slices, both intracellular cytosolic Ca(2+)-dependent PLA(2) (cPLA(2)) and Ca(2+)-independent PLA(2) (iPLA(2)) have been implicated in mechanisms of synaptic plasticity underlying memory processes. In mice, intraperitoneal injections of a selective iPLA(2) inhibitor impaired spatial learning. Accordingly, reduced cPLA(2) and iPLA(2) activities were found in postmortem hippocampus of patients with Alzheimer's disease. OBJECTIVE This study investigates the effects of injections of PLA(2) inhibitors directly into rat hippocampus on the acquisition of short-term (STM) and long-term memory (LTM) of a one-trial step-down inhibitory avoidance (IA) task. METHODS Wistar rats were bilaterally implanted with cannulae in the CA1 region of the dorsal hippocampus. After surgery, the rats received bilateral injections of a vehicle, or of dual cPLA(2) and iPLA(2) inhibitors (MAFP or PACOCF(3)), or a selective iPLA(2) inhibitor (bromoenol lactone) before training in IA. The animals were tested 1.5 h (for STM) and 24 h (for LTM) after training. RESULTS Significant inhibition of iPLA(2) activity in rat hippocampus impaired acquisition of STM and LTM. Memory impairment did not result from neuronal death after iPLA(2) inhibition. Moreover, IA training per se increased significantly hippocampal PLA(2) activity. CONCLUSION The present results suggest a functional effect of hippocampal PLA(2) on the neurochemistry of memory acquisition and support the hypothesis that reduced PLA(2) activity may contribute to memory impairment in Alzheimer's disease.
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Affiliation(s)
- Evelin L Schaeffer
- Laboratory of Neuroscience (LIM-27), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, Brazil
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Pascale A, Amadio M, Scapagnini G, Lanni C, Racchi M, Provenzani A, Govoni S, Alkon DL, Quattrone A. Neuronal ELAV proteins enhance mRNA stability by a PKCalpha-dependent pathway. Proc Natl Acad Sci U S A 2005; 102:12065-70. [PMID: 16099831 PMCID: PMC1189326 DOI: 10.1073/pnas.0504702102] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
More than 1 in 20 human genes bear in the mRNA 3' UTR a specific motif called the adenine- and uridine-rich element (ARE), which posttranscriptionally determines its expression in response to cell environmental signals. ELAV (embryonic lethal abnormal vision) proteins are the only known ARE-binding factors that are able to stabilize the bound mRNAs, thereby positively controlling gene expression. Here, we show that in human neuroblastoma SH-SY5Y cells, neuron-specific ELAV (nELAV) proteins (HuB, HuC, and HuD) are up-regulated and redistributed by 15 min of treatment with the activators of PKC phorbol esters and bryostatin-1. PKC stimulation also induces nELAV proteins to colocalize with the translocated PKCalpha isozyme preferentially on the cytoskeleton, with a concomitant increase of nELAV threonine phosphorylation. The same treatment promotes stabilization of growth-associated protein 43 (GAP-43) mRNA, a well known nELAV target, and induces an early increase in GAP-43 protein concentration, again only in the cytoskeletal cell fraction. Genetic or pharmacological inactivation of PKCalpha abolishes nELAV protein cytoskeletal up-regulation, GAP-43 mRNA stabilization, and GAP-43 protein increase, demonstrating the primary role of this specific PKC isozyme in the cascade of nELAV recruitment. Finally, in vivo PKC activation is associated with an up-regulation of nELAV proteins in the hippocampal rat brain. These findings suggest a model for gene expression regulation by nELAV proteins through a PKCalpha-dependent pathway that is relevant for the cellular programs in which ARE-mediated control plays a pivotal role.
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Affiliation(s)
- Alessia Pascale
- Department of Experimental and Applied Pharmacology, University of Pavia, Via Taramelli 14, 27100 Pavia, Italy.
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Mandel S, Weinreb O, Amit T, Youdim MBH. Mechanism of neuroprotective action of the anti-Parkinson drug rasagiline and its derivatives. ACTA ACUST UNITED AC 2005; 48:379-87. [PMID: 15850677 DOI: 10.1016/j.brainresrev.2004.12.027] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 12/09/2004] [Indexed: 01/01/2023]
Abstract
The mitochondria are directly involved in cell survival and death. Drugs that protect mitochondria viability and prevent apoptotic cascade mechanisms involved in mitochondrial permeability transition pore (MPTp) will be cytoprotective. Rasagiline (N-propargyl-1R-aminoindan) is a novel, highly potent irreversible monoamine oxidase (MAO) B inhibitor, anti-Parkinson drug. Unlike selegiline, rasagiline is not derived from amphetamine, is not metabolized to neurotoxic l-methamphetamine derivative, nor does it have sympathomimetic activity. Rasagiline is effective as monotherapy or adjunct to L-dopa for patients with early and late Parkinson's disease (PD), and adverse events do not occur with greater frequency in subjects receiving rasagiline than those on placebo. Controlled studies indicate that it might have a disease-modifying effect in PD that may be related to neuroprotection. Its S-isomer, TVP1022, is a relatively inactive MAO inhibitor. However, both drugs have similar neuroprotective activities in neuronal cell cultures in response to various neurotoxins and in vivo (global ischemia, neurotrauma, head injury, anoxia, etc.), indicating that MAO inhibition is not a pre-requisite for neuroprotection. Structure activity studies have shown that the neuroprotective activity is associated with the propargyl moiety of rasagiline which protects mitochondrial viability and MPTp by activating Bcl-2 and protein kinase C (PKC), and down regulating pro-apoptotic FAS and Bax. Rasagiline and its derivatives also process amyloid precursor protein (APP) to the neuroprotective-neurotrophic soluble APP alpha (sAPPalpha) by PKC and MAP kinase-dependent activation of alpha-secretase. The neuroprotective activity of propargylamine has led us to develop novel bifunctional neuroprotective iron-chelating MAO-inhibiting drugs possessing propargyl moiety for the treatment of other neurodegenerative diseases.
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Affiliation(s)
- Silvia Mandel
- Eve Topf and NPF Centers of Excellence for Neurodegenerative Diseases Research, Israel
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Reznichenko L, Amit T, Youdim MBH, Mandel S. Green tea polyphenol (-)-epigallocatechin-3-gallate induces neurorescue of long-term serum-deprived PC12 cells and promotes neurite outgrowth. J Neurochem 2005; 93:1157-67. [PMID: 15934936 DOI: 10.1111/j.1471-4159.2005.03085.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Our previous studies have shown that the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) prevents neuronal cell death caused by several neurotoxins. The present study sought to determine the neuroprotective effect of EGCG when it is administered after the induction of cell damage ('neurorescue'). In an attempt to imitate a progressive mode of death, PC12 cells were initially subjected to serum-starvation conditions for a period of 1 or 3 days before administration of EGCG (0.1-10 microM) for up to 3 days. In spite of the high percentage of cell death, single or repetitive administration of EGCG (1 microM) significantly attenuated cell death. The neurorescue effect of EGCG was abolished by pre-treatment with the protein kinase C inhibitor GF109203X (2.5 microM), suggesting the involvement of the protein kinase C pathway in neurorescue by the drug. This is consistent with the rapid (15 min) translocation of the protein kinase C alpha isoform to the cell membrane in response to EGCG. The correlative neurite outgrowth activity of EGCG on PC12 cells may also contribute to its neurorescue effect. The present findings suggest that EGCG may have a positive impact on aging and neurodegenerative diseases to retard or perhaps even reverse the accelerated rate of neuronal degeneration.
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Affiliation(s)
- L Reznichenko
- Eve Topf and NPF Centers of Excellence for Neurodegenerative Diseases Research and Department of Pharmacology, Technion-Rappaport Family Faculty of Medicine, Haifa, Israel
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Mandel SA, Avramovich-Tirosh Y, Reznichenko L, Zheng H, Weinreb O, Amit T, Youdim MBH. Multifunctional Activities of Green Tea Catechins in Neuroprotection. Neurosignals 2005; 14:46-60. [PMID: 15956814 DOI: 10.1159/000085385] [Citation(s) in RCA: 262] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Accepted: 03/01/2005] [Indexed: 12/16/2022] Open
Abstract
Many lines of evidence suggest that oxidative stress resulting in reactive oxygen species (ROS) generation and inflammation play a pivotal role in the age-associated cognitive decline and neuronal loss in neurodegenerative diseases including Alzheimer's (AD), Parkinson's (PD) and Huntington's diseases. One cardinal chemical pathology observed in these disorders is the accumulation of iron at sites where the neurons die. The buildup of an iron gradient in conjunction with ROS (superoxide, hydroxyl radical and nitric oxide) are thought to constitute a major trigger in neuronal toxicity and demise in all these diseases. Thus, promising future treatment of neurodegenerative diseases and aging depends on availability of effective brain permeable, iron-chelatable/radical scavenger neuroprotective drugs that would prevent the progression of neurodegeneration. Tea flavonoids (catechins) have been reported to possess potent iron-chelating, radical-scavenging and anti-inflammatory activities and to protect neuronal death in a wide array of cellular and animal models of neurological diseases. Recent studies have indicated that in addition to the known antioxidant activity of catechins, other mechanisms such as modulation of signal transduction pathways, cell survival/death genes and mitochondrial function, contribute significantly to the induction of cell viability. This review will focus on the multifunctional properties of green tea and its major component (-)-epigallocatechin-3-gallate (EGCG) and their ability to induce neuroprotection and neurorescue in vitro and in vivo. In particular, their transitional metal (iron and copper) chelating property and inhibition of oxidative stress.
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Affiliation(s)
- Silvia A Mandel
- Eve Topf and USA National Parkinson Foundation Centers of Excellence for Neurodegenerative Diseases Research, Technion-Faculty of Medicine, Haifa, Israel
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Tayebi Meybodi K, Vakili Zarch A, Zarrindast MR, Djahanguiri B. Effects of ultra-low doses of morphine, naloxone and ethanol on morphine state-dependent memory of passive avoidance in mice. Behav Pharmacol 2005; 16:139-45. [PMID: 15864068 DOI: 10.1097/00008877-200505000-00002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This experiment examined and compared the effects of pre-test administration of morphine, naloxone and ethanol, at doses in the range of milligram/kg to those of nanogram/kg, on morphine state-dependent learning in a step-down passive avoidance task in mice. Morphine (5 mg/kg) administered before training impaired retention tested 24 hours later, but when the same dose of morphine was also administered before the test, the retention was significantly restored. Pre-training administration of 10 or 20 ng/kg (i.p.) of morphine had no effect, but when co-administered with the same drug at 5 mg/kg (s.c.), it prevented significantly the memory recall improvement after the administration of morphine (5 mg/kg, s.c.) alone. In a parallel experiment, naloxone (5 mg/kg) prevented the memory recall improvement by morphine. However, the effects of naloxone at doses in the range of ng/kg were opposite to those of milligram doses of the same drug. Pre-test administration of ethanol (1 mg/kg) improved memory recall and mimicked the effects of pre-test morphine administration. At doses in the nanogram range, the effects of ethanol were opposite those of mg/kg of the drug. A review of the literature indicates that, for several drugs and chemicals, the effects of nanogram doses are the opposite of the effects of milligrams, because different doses have different sites as well as mechanisms of actions. In conclusion, from the above results one may suggest that, in determination of the dose-response of at least some drugs, the study of the effects of doses much lower than two orders of magnitude of the minimum effective dose are warranted.
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Affiliation(s)
- K Tayebi Meybodi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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40
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Célérier A, Piérard C, Rachbauer D, Sarrieau A, Béracochéa D. Contextual and serial discriminations: a new learning paradigm to assess simultaneously the effects of acute stress on retrieval of flexible or stable information in mice. Learn Mem 2004; 11:196-204. [PMID: 15054135 PMCID: PMC379690 DOI: 10.1101/lm.65604] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The present study was aimed at simultaneously determining on the same subject, the effects of stress on retrieval of flexible (contextual or temporal) or stable (spatial) information. Three behavioral paradigms carried out in a four-hole board were designed as follows: (1) Simple Discrimination (SD), in which mice learned a single discrimination; (2) Contextual and Serial Discriminations (CSD), in which mice learned two successive discriminations on two different internal contexts; (3) Spatial Serial Discriminations (SSD), in which mice learned two successive discriminations on an identical internal context. The stressor (three inescapable electric footshocks) was delivered 5 min before retention, occurring 5 min or 24 h after acquisition. Results showed that this stressor increased plasmatic corticosterone levels and fear reactivity in an elevated-plus-maze, as compared with nonstressed mice. The stressor reversed the normal pattern of retrieval observed in nonstressed controls in the CSD task, this effect being context dependent, as it was not observed in the SSD task. Overall, our study shows that stress affected the retrieval of flexible and old information, but spared the retrieval of stable or recent ones. Therefore, these behavioral paradigms allow us to study simultaneously, on the same animal, the effects of stress on distinct forms of memory retrieval.
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Affiliation(s)
- Aurélie Célérier
- Laboratoire de Neurosciences Cognitives, Unite Mixte de Recherche Centre National Recherche Scientifique 5601, Bâtiment de Biologie Animale, 33405 Talence Cedex, France
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Jafari MR, Zarrindast MR, Djahanguiri B. Effects of different doses of glucose and insulin on morphine state-dependent memory of passive avoidance in mice. Psychopharmacology (Berl) 2004; 175:457-62. [PMID: 15042277 DOI: 10.1007/s00213-004-1841-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RATIONALE Behavioral effects of morphine, including its effect on memory, have been demonstrated to be influenced by glucose pretreatment. The measurement of step-down latency in passive avoidance has been used to study memory in laboratory animals. The pre-training injection of 5 mg/kg morphine impaired memory, which was restored when 24 h later the same dose of the drug was administered. OBJECTIVES To investigate the effects of glucose and insulin alone or in combination with morphine, on pre-test day, on memory recall in mice. METHODS The effects of different doses of glucose (50, 100, and 200 mg/kg, IP) and insulin (5, 10, and 20 IU/kg, IP) alone or in combination with morphine, have been studied in mice. The blood glucose level and locomotor activity of the animals were also measured. RESULTS Although the administration of glucose alone showed no effect on morphine-induced memory impairment, its co-administration with morphine resulted in a significant and dose-dependent memory enhancement compared with the effects of morphine administration alone. Like glucose, the administration of different doses of insulin alone produced no change in the memory, but when the drug was co-administered with morphine, it significantly reduced morphine-induced memory retrieval. The effect of insulin was the opposite of glucose. None of the animals subjected to insulin treatment showed convulsions. CONCLUSIONS Glucose is suggested to increase, on the test day, the morphine-induced memory enhancement by three different mechanisms: cholinergic or opioidergic modulations, or regulation of the ATP-dependent potassium channels.
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Affiliation(s)
- M R Jafari
- Department of Pharmacology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
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Cammarota M, Barros DM, Vianna MRM, Bevilaqua LRM, Coitinho A, Szapiro G, Izquierdo LA, Medina JH, Izquierdo I. The transition from memory retrieval to extinction. AN ACAD BRAS CIENC 2004; 76:573-82. [PMID: 15334255 DOI: 10.1590/s0001-37652004000300011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Memory is measured by measuring retrieval. Retrieval is often triggered by the conditioned stimulus (CS); however, as known since Pavlov, presentation of the CS alone generates extinction. One-trial avoidance (IA) is a much used conditioned fear paradigm in which the CS is the safe part of a training apparatus, the unconditioned stimulus (US) is a footshock and the conditioned response is to stay in the safe area. In IA, retrieval is measured without the US, as latency to step-down from the safe area (i.e., a platform). Extinction is installed at the moment of the first unreinforced test session, as clearly shown by the fact that many drugs, including PKA, ERK and protein synthesis inhibitors as well as NMDA receptor antagonists, hinder extinction when infused into the hippocampus or the basolateral amygdala at the moment of the first test session but not later. Some, but not all the molecular systems required for extinction are also activated by retrieval, further endorsing the hypothesis that although retrieval is behaviorally and biochemically necessary for the generation of extinction, this last process constitutes a new learning secondary to the unreinforced expression of the original trace.
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Affiliation(s)
- Martín Cammarota
- Centro de Memória, ICS, Departamento de Bioquímica, Universidade Federal Do Rio Grande Do Sul, 90035-003 Porto Alegre, RS, Brasil
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Vakili A, Tayebi K, Jafari MR, Zarrindast MR, Djahanguiri B. EFFECT OF ETHANOL ON MORPHINE STATE-DEPENDENT LEARNING IN THE MOUSE: INVOLVEMENT OF GABAERGIC, OPIOIDERGIC AND CHOLINERGIC SYSTEMS. Alcohol Alcohol 2004; 39:427-32. [PMID: 15289212 DOI: 10.1093/alcalc/agh084] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS We have studied the effect of acute administration of ethanol when it replaced morphine in step-down passive avoidance task on the test day and the effects of antagonists of GABAergic, opioidergic and cholinergic systems on ethanol actions. METHODS Morphine (5 mg/kg, s.c.) was administered as pre-training and 24 h later as pre-test drug, and the latencies were measured in mice. Ethanol (0.125, 0.25, 1 and 2 g/kg, i.p.) was administered instead of pre-test morphine. Antagonists of GABAergic (bicuculline 0.5, 1 and 2 mg/kg, i.p.), opioidergic (naloxone 0.06, 0.25 and 1 mg/kg, i.p.) and cholinergic (atropine 0.625 and 1.25 mg/kg, i.p. and mecamylamine 0.5, 1 and 2 mg/kg, i.p.) systems were co-administered with ethanol (0.25 g/kg, i.p.) on the test day. Locomotor activity was measured as well. RESULTS Pre-training morphine impaired the memory on the test day which was restored when the same dose of morphine was used as pre-test drug. All four doses of ethanol replaced pre-test morphine and enhanced the memory. This effect was prevented by all of the above antagonists. No significant changes were seen in the locomotor activity of the animals treated with ethanol or antagonists compared to the proper controls. CONCLUSIONS GABAergic, endogenous opioidergic and cholinergic systems are involved in the memory recall improvement by ethanol when it replaced morphine on the test day. A review of the literature suggests other possibilities such as the release of intermediate neurotransmitters.
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Affiliation(s)
- A Vakili
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Sato T, Tanaka KI, Teramoto T, Ohnishi Y, Hirate K, Irifune M, Nishikawa T. Facilitative effect of a novel AVP fragment analog, NC-1900, on memory retention and recall in mice. Peptides 2004; 25:1139-46. [PMID: 15245873 DOI: 10.1016/j.peptides.2004.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 03/31/2004] [Accepted: 04/01/2004] [Indexed: 11/16/2022]
Abstract
In order to determine the mechanism of action of a new AVP(4-9) analog, NC-1900, on memory processes, memory retention and retrieval tests were conducted in a step-through passive avoidance (PA) task in mice. The administration of NC-1900 facilitated memory retention and retrieval in the PA task through vasopressin1A (V1A) receptors but not V2 receptors. The effect of NC-1900 on memory retention test performance appeared to be due to activation of the protein kinase C (PKC) signaling pathway via V1A receptors; however, the modulation of PKC was not essential for the facilitative effect of the new peptide in the retrieval test. The facilitation of memory retrieval by NC-1900 may also be mediated by other non-PKC-dependent signaling pathways, such as the phospholipase C-inositol trisphosphate pathway.
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Affiliation(s)
- Tomoaki Sato
- Department of Applied Pharmacology, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka 8, 890-8544, Japan.
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Youdim MBH, Bar Am O, Yogev-Falach M, Weinreb O, Maruyama W, Naoi M, Amit T. Rasagiline: Neurodegeneration, neuroprotection, and mitochondrial permeability transition. J Neurosci Res 2004; 79:172-9. [PMID: 15573406 DOI: 10.1002/jnr.20350] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondria are involved directly in cell survival and death. The assumption has been made that drugs that protect mitochondrial viability and prevent apoptotic cascade-induced mitochondrial permeability transition pore (MPTp) opening will be cytoprotective. Rasagiline (N-propargyl-1R-aminoindan) is a novel, highly potent irreversible monoamine oxidase (MAO) B inhibitor anti-Parkinson drug. Unlike selegiline, it is not derived from amphetamine, and is not metabolized to neurotoxic L-methamphetamine derivative. In addition, it does not have sympathomimetic activity. Rasagiline is effective as monotherapy or adjunct to levodopa for patients with early and late Parkinson's disease (PD) and adverse events do not occur with greater frequency in subjects receiving rasagiline than in those on placebo. Phase III controlled studies indicate that it might have a disease-modifying effect in PD that may be related to its neuroprotective activity. Its S isomer, TVP1022, is more than 1,000 times less potent as an MAO inhibitor. Both drugs, however, have neuroprotective activity in neuronal cell cultures in response to various neurotoxins, and in vivo in response to global ischemia, neurotrauma, head injury, anoxia, etc., indicating that MAO inhibition is not a prerequisite for neuroprotection. Their neuroprotective effect has been demonstrated to be associated directly with the propargylamine moiety, which protects mitochondrial viability and MTPp by activating Bcl-2 and protein kinase C (PKC) and by downregulating the proapoptotic FAS and Bax protein families. Rasagiline and its derivatives also process amyloid precursor protein (APP) to the neuroprotective, neurotrophic, soluble APP alpha (sAPPalpha) by PKC- and MAP kinase-dependent activation of alpha-secretase. The identification of the propargylamine moiety as the neuroprotective component of rasagiline has led us to development of novel bifunctional anti-Alzheimer drugs (ladostigil) possessing cholinesterase and brain-selective MAO inhibitory activity and a similar neuroprotective mechanism of action.
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Affiliation(s)
- Moussa B H Youdim
- Eve Topf and USA National Parkinson Foundation Centers of Excellence for Neurodegenerative Diseases Research and Department of Pharmacology, Technion-Faculty of Medicine, 31096 Haifa, Israel.
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Cognitive strategy-specific increases in phosphorylated cAMP response element-binding protein and c-Fos in the hippocampus and dorsal striatum. J Neurosci 2003. [PMID: 12716964 DOI: 10.1523/jneurosci.23-08-03547.2003] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Extensive research has shown that the hippocampus and striatum have dissociable roles in memory and are necessary for "place" and "response" learning, respectively. In the present study, rats were trained on a cross maze task that could be solved by either a place or a response strategy, and the strategy used was determined by a probe trial. Phosphorylated cAMP response element-binding protein (pCREB) and c-Fos immunoreactivity (IR) were measured in the hippocampus and striatum either immediately or 1 hr after cross maze training. Immediately after training, pCREB-IR and c-Fos-IR were significantly higher in the hippocampus and striatum of trained rats than in control rats matched for motor activity, but the increase was independent of the strategy revealed at probe. One hour after training, however, pCREB-IR and c-Fos-IR were sustained in the hippocampal pyramidal and granule cell layers of place learners but returned to basal levels among response learners. In addition, pCREB-IR was sustained in the dorsomedial and dorsolateral striatum of response learners but returned to basal levels among place learners. There were no differences between place and response learners in c-Fos-IR in the striatum at either time point. The present results indicate that cross maze training causes an initial activation of transcription factors in both the hippocampus and striatum. Formation of memory for a place strategy, however, is related to sustained phosphorylation of CREB and expression of c-Fos for at least 1 hr in the hippocampus, whereas formation of memory for a response strategy is related to phosphorylation of CREB in the striatum.
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Bevilaqua LRM, Kerr DS, Medina JH, Izquierdo I, Cammarota M. Inhibition of hippocampal Jun N-terminal kinase enhances short-term memory but blocks long-term memory formation and retrieval of an inhibitory avoidance task. Eur J Neurosci 2003; 17:897-902. [PMID: 12603281 DOI: 10.1046/j.1460-9568.2003.02524.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Learning initiates a series of plastic events the occurrence of which are required for the storage of information related to the training experience. Several lines of evidence indicate that, in the rat hippocampus, different members of the family of mitogen-activated protein kinases (MAPK) play a key role in the onset of such plastic events. Using SP600125, the newly developed inhibitor of the MAPK c-Jun amino-terminal kinase (JNK), we show a direct involvement of this protein kinase in mnemonic processes. The intra-CA1 infusion of SP600125, at a dose that in naïve animals significantly reduced the phosphorylation levels of c-Jun without affecting the activity of ERK1/2 or p38 MAPK, enhanced short-term memory (STM) but blocked long-term memory (LTM) formation and retrieval of an inhibitory avoidance learning task. No action of this drug on locomotor/exploratory activity or general anxiety state could be detected. The significance of these results is discussed in the context of others describing the independence of LTM from STM.
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Affiliation(s)
- Lia R M Bevilaqua
- Centro de Memória, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Ramiro Barcellos 2600-Anexo-Porto Alegre, RS 90035-003, Brazil
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48
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Olariu A, Yamada K, Mamiya T, Hefco V, Nabeshima T. Memory impairment induced by chronic intracerebroventricular infusion of beta-amyloid (1-40) involves downregulation of protein kinase C. Brain Res 2002; 957:278-86. [PMID: 12445970 DOI: 10.1016/s0006-8993(02)03608-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Signaling pathways underlying the cognitive deficit of the Alzheimer's disease (AD) are not completely understood. Protein kinase C (PKC), a major neuronal protein plays a critical role in cellular signal transduction and it is known to be subjected to modulation in AD. We showed previously that, chronic infusion of beta-amyloid (1-40) into rat cerebroventricle leads to deficit in spatial and non-spatial memory formation. As an attempt to identify the cellular correlates of the memory deficit, in the present study we investigated the PKC activation in different brain areas. Chronic infusion of beta-amyloid (1-40) for 14 days into the rat cerebroventricle decreased the activity of soluble protein kinase C (PKC) in the hippocampus. Subcellular translocation of PKC to membrane fraction in hippocampal slices of rats treated with beta-amyloid (1-40) was completely abolished under acute stimulation with 0.5 microM phorbol-dibutyrate (PDBu). We also reported a decreased affinity (k(D)) for PDBu binding in the hippocampus, cerebral cortex and striatum. The total number of binding sites for PDBu (B(max)) was increased, in the three brain areas analyzed on the day 14, but the changes were not statistically significant. Our data indicate that chronic accumulation of beta-amyloid (1-40) into the rat brain reduced activation of PKC, effect that would substantially contribute to the memory deficit found in these animals.
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Affiliation(s)
- Ana Olariu
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, 65 Tsuruma-cho, Showa-ku, Nagoya, Japan
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Szapiro G, Galante JM, Barros DM, Levi de Stein M, Vianna MRM, Izquierdo LA, Izquierdo I, Medina JH. Molecular mechanisms of memory retrieval. Neurochem Res 2002; 27:1491-8. [PMID: 12512953 DOI: 10.1023/a:1021648405461] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Memory retrieval is a fundamental component or stage of memory processing. In fact, retrieval is the only possible measure of memory. The ability to recall past events is a major determinant of survival strategies in all species and is of paramount importance in determining our uniqueness as individuals. Most biological studies of memory using brain lesion and/or gene manipulation techniques cannot distinguish between effects on the molecular mechanisms of the encoding or consolidation of memories and those responsible for their retrieval from storage. Here we examine recent findings indicating the major molecular steps involved in memory retrieval in selected brain regions of the mammalian brain. Together the findings strongly suggest that memory formation and retrieval may share some molecular mechanisms in the hippocampus and that retrieval initiates extinction requiring activation of several signaling cascades and protein synthesis.
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Affiliation(s)
- German Szapiro
- Instituto de Biologia Celular y Neurociencias, Facultad de Medicina, UBA, Paraguay 2155, piso 3, 1121 Buenos Aires, Argentina
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50
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Izquierdo I, Vianna MR, Izquierdo LA, Barros DM, Szapiro G, Coitinho AS, Muller L, Cammarota M, Bevilaqua LR, Medina JH. Memory retrieval and its lasting consequences. Neurotox Res 2002; 4:573-593. [PMID: 12754168 DOI: 10.1080/10298420290031441] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Many, if not all psychiatric diseases are accompanied by memory disturbances, in particular, the dementias, schizophrenia, and, to an extent, mood disorders. Anxiety and stress, on the other hand, cause important alterations of memory, particularly its retrieval. Here we discuss several new findings on the basic mechanisms of consolidation, retrieval and extinction of a prototype form of episodic memory in the rat: conditioned fear. The findings point the way for investigations on the pathology of these aspects of memory in health and disease. Emphasis is placed on the parallel processing of retrieval in several cortical areas, on the links between retrieval and the onset of extinction, on the fact that extinction involves new learning requiring gene expression, and on the differences between the retrieval of recent or remote long-term memories.
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Affiliation(s)
- Iván Izquierdo
- Departamento de Bioquímica, Centro de Memoria, Instituto de Ciencias Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brasil
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