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Ueno H, Takahashi Y, Murakami S, Wani K, Miyazaki T, Matsumoto Y, Okamoto M, Ishihara T. Comprehensive behavioral study of C57BL/6.KOR-ApoE shl mice. Transl Neurosci 2023; 14:20220284. [PMID: 37396111 PMCID: PMC10314129 DOI: 10.1515/tnsci-2022-0284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 07/04/2023] Open
Abstract
Background Apolipoprotein E (ApoE) is associated with Alzheimer's disease (AD) and cognitive dysfunction in elderly individuals. There have been extensive studies on behavioral abnormalities in ApoE-deficient (Apoeshl) mice, which have been described as AD mouse models. Spontaneously hyperlipidemic mice were discovered in 1999 as ApoE-deficient mice due to ApoE gene mutations. However, behavioral abnormalities in commercially available Apoeshl mice remain unclear. Accordingly, we aimed to investigate the behavioral abnormalities of Apoeshl mice. Results Apoeshl mice showed decreased motor skill learning and increased anxiety-like behavior toward heights. Apoeshl mice did not show abnormal behavior in the Y-maze test, open-field test, light/dark transition test, and passive avoidance test. Conclusion Our findings suggest the utility of Apoeshl mice in investigating the function of ApoE in the central nervous system.
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Affiliation(s)
- Hiroshi Ueno
- Department of Medical Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama, 701-0193, Japan
| | - Yu Takahashi
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Shinji Murakami
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Kenta Wani
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Tetsuji Miyazaki
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Yosuke Matsumoto
- Department of Neuropsychiatry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan
| | - Motoi Okamoto
- Department of Medical Technology, Graduate School of Health Sciences, Okayama University, Okayama, 700-8558, Japan
| | - Takeshi Ishihara
- Department of Psychiatry, Kawasaki Medical School, Kurashiki, 701-0192, Japan
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OUP accepted manuscript. Brain 2022; 145:2250-2275. [DOI: 10.1093/brain/awac096] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 01/21/2022] [Accepted: 01/23/2022] [Indexed: 11/13/2022] Open
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de Bem AF, Krolow R, Farias HR, de Rezende VL, Gelain DP, Moreira JCF, Duarte JMDN, de Oliveira J. Animal Models of Metabolic Disorders in the Study of Neurodegenerative Diseases: An Overview. Front Neurosci 2021; 14:604150. [PMID: 33536868 PMCID: PMC7848140 DOI: 10.3389/fnins.2020.604150] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/24/2020] [Indexed: 12/21/2022] Open
Abstract
The incidence of metabolic disorders, as well as of neurodegenerative diseases—mainly the sporadic forms of Alzheimer’s and Parkinson’s disease—are increasing worldwide. Notably, obesity, diabetes, and hypercholesterolemia have been indicated as early risk factors for sporadic forms of Alzheimer’s and Parkinson’s disease. These conditions share a range of molecular and cellular features, including protein aggregation, oxidative stress, neuroinflammation, and blood-brain barrier dysfunction, all of which contribute to neuronal death and cognitive impairment. Rodent models of obesity, diabetes, and hypercholesterolemia exhibit all the hallmarks of these degenerative diseases, and represent an interesting approach to the study of the phenotypic features and pathogenic mechanisms of neurodegenerative disorders. We review the main pathological aspects of Alzheimer’s and Parkinson’s disease as summarized in rodent models of obesity, diabetes, and hypercholesterolemia.
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Affiliation(s)
- Andreza Fabro de Bem
- Department of Physiological Sciences, Institute of Biology, University of Brasilia, Brazilia, Brazil
| | - Rachel Krolow
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Hémelin Resende Farias
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Victória Linden de Rezende
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Daniel Pens Gelain
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - José Cláudio Fonseca Moreira
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - João Miguel das Neves Duarte
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden.,Wallenberg Centre for Molecular Medicine, Faculty of Medicine, Lund University, Lund, Sweden
| | - Jade de Oliveira
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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Jamal M, Ito A, Tanaka N, Miki T, Takakura A, Suzuki S, Ameno K, Kinoshita H. The Role of Apolipoprotein E and Ethanol Exposure in Age-Related Changes in Choline Acetyltransferase and Brain-Derived Neurotrophic Factor Expression in the Mouse Hippocampus. J Mol Neurosci 2018; 65:84-92. [PMID: 29717403 DOI: 10.1007/s12031-018-1074-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/20/2018] [Indexed: 12/17/2022]
Abstract
Disruption of apolipoprotein E (APOE) is responsible for age-dependent neurodegeneration and cognitive impairment. Elderly individuals are more sensitive than young individuals to the effects of ethanol (EtOH), particularly those affecting cognition. We investigated the role of APOE deficiency and EtOH exposure on age-dependent alterations in choline acetyltransferase (ChAT) and brain-derived neurotrophic factor (BDNF) mRNA and protein expression in the mouse hippocampus. Three-month-old (young) and 12-month-old (aged) ApoE-knockout (ApoE-KO) and wild-type (WT) mice were treated with saline or 2 g/kg EtOH, and the bilateral hippocampus was collected after 60 min for real-time PCR and western blotting analyses. ChAT (P < 0.01) and BDNF (P < 0.01) expression were significantly decreased in both young and aged saline- and EtOH-treated ApoE-KO mice versus young and aged saline- and EtOH-treated WT mice. Aged saline- and EtOH-treated ApoE-KO mice exhibited greater differences in ChAT and BDNF expression (P < 0.01) than young saline- and EtOH-treated ApoE-KO mice. Aged EtOH-treated WT mice also exhibited larger decreases in BDNF expression (P < 0.01)-but not in ChAT expression-than young EtOH-treated WT mice. EtOH decreased ChAT and BDNF expression in both young (P < 0.01) and aged (P < 0.01) ApoE-KO mice versus EtOH-free ApoE-KO mice of the same age. EtOH also decreased BDNF expression in aged (P < 0.01) WT mice versus EtOH-free aged WT mice. In summary, these results suggest that APOE deficiency and EtOH exposure cause age-dependent decreases in ChAT and BDNF in the hippocampus. Importantly, the decreases in ChAT and BDNF were greater in aged EtOH-treated mice, particularly those lacking APOE, raising the possibility that APOE-deficient individuals who consume alcohol may be at greater risk of memory deficit.
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Affiliation(s)
- Mostofa Jamal
- Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan.
| | - Asuka Ito
- Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan
| | - Naoko Tanaka
- Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan
| | - Takanori Miki
- Department of Anatomy and Neurobiology, Faculty of Medicine, Kagawa University, Kita, Japan
| | - Ayaka Takakura
- Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan
| | - Shingo Suzuki
- Department of Anatomy and Neurobiology, Faculty of Medicine, Kagawa University, Kita, Japan
| | - Kiyoshi Ameno
- Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan
| | - Hiroshi Kinoshita
- Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa, 761-0793, Japan
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Age-Related Changes in the Behavior of Apolipoprotein E Knockout Mice. Behav Sci (Basel) 2018; 8:bs8030033. [PMID: 29510495 PMCID: PMC5867486 DOI: 10.3390/bs8030033] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/21/2018] [Accepted: 02/26/2018] [Indexed: 12/16/2022] Open
Abstract
The knockout mouse model, B6.129P2-Apoetm1Unc is homozygotic for the Apolipoprotein E (ApoE) deletion; thus, it is capable of developing hyperlipidemia and atherosclerosis but ApoE is also a lipid-transport protein abundantly expressed in most neurons in the central nervous system, so these animals could also be models of neurodegenerative diseases. The aim of this study was to determine age-related changes in spontaneous behavior and in learning and memory of Apolipoprotein E knockout mice. Spontaneous behavioral measurements included sleeping pattern, motor coordination and balance by rotarod and open field activity, whereas learning and memory tests included forced alternation in Y-maze, novel object recognition and passive avoidance conditioning. Significant behavioral differences between aged knockout mice and age-matched wild type strain, C57Bl/6 were found in all the behavioral tests, except for the rotarod test. Genetically’ modified mice exhibited less huddling contact during sleeping, decreased locomotor activity in novel environments and in learning and memory deficits. These results are consistent with the cognitive impairment and memory loss seen as the earliest clinical symptoms in neurodegenerative disorders such as Alzheimer’s disease. The ApoE knockout mice might therefore be an appropriate model for studying the underlying mechanisms involved in behavioral changes caused by neurodegenerative diseases as well as for evaluating new therapies for these pathologies.
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Gratwicke J, Kahan J, Zrinzo L, Hariz M, Limousin P, Foltynie T, Jahanshahi M. The nucleus basalis of Meynert: A new target for deep brain stimulation in dementia? Neurosci Biobehav Rev 2013; 37:2676-88. [DOI: 10.1016/j.neubiorev.2013.09.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
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The Influence of Apolipoprotein E Epsilon4 Polymorphism on qEEG Profiles in Healthy Young Females: A Resting EEG Study. Brain Topogr 2012; 25:431-42. [DOI: 10.1007/s10548-012-0229-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 04/23/2012] [Indexed: 12/23/2022]
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8
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Terry AV, Callahan PM, Hall B, Webster SJ. Alzheimer's disease and age-related memory decline (preclinical). Pharmacol Biochem Behav 2011; 99:190-210. [PMID: 21315756 DOI: 10.1016/j.pbb.2011.02.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 01/21/2011] [Accepted: 02/01/2011] [Indexed: 01/05/2023]
Abstract
An unfortunate result of the rapid rise in geriatric populations worldwide is the increasing prevalence of age-related cognitive disorders such as Alzheimer's disease (AD). AD is a devastating neurodegenerative illness that is characterized by a profound impairment of cognitive function, marked physical disability, and an enormous economic burden on the afflicted individual, caregivers, and society in general. The rise in elderly populations is also resulting in an increase in individuals with related (potentially treatable) conditions such as "Mild Cognitive Impairment" (MCI) which is characterized by a less severe (but abnormal) level of cognitive impairment and a high-risk for developing dementia. Even in the absence of a diagnosable disorder of cognition (e.g., AD and MCI), the perception of increased forgetfulness and declining mental function is a clear source of apprehension in the elderly. This is a valid concern given that even a modest impairment of cognitive function is likely to be associated with significant disability in a rapidly evolving, technology-based society. Unfortunately, the currently available therapies designed to improve cognition (i.e., for AD and other forms of dementia) are limited by modest efficacy and adverse side effects, and their effects on cognitive function are not sustained over time. Accordingly, it is incumbent on the scientific community to develop safer and more effective therapies that improve and/or sustain cognitive function in the elderly allowing them to remain mentally active and productive for as long as possible. As diagnostic criteria for memory disorders evolve, the demand for pro-cognitive therapeutic agents is likely to surpass AD and dementia to include MCI and potentially even less severe forms of memory decline. The purpose of this review is to provide an overview of the contemporary therapeutic targets and preclinical pharmacologic approaches (with representative drug examples) designed to enhance memory function.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology and Small Animal Behavior Core, Medical College of Georgia, Augusta, GA 30912, USA.
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Bihaqi SW, Sharma M, Singh AP, Tiwari M. Neuroprotective role of Convolvulus pluricaulis on aluminium induced neurotoxicity in rat brain. JOURNAL OF ETHNOPHARMACOLOGY 2009; 124:409-415. [PMID: 19505562 DOI: 10.1016/j.jep.2009.05.038] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2009] [Revised: 05/19/2009] [Accepted: 05/29/2009] [Indexed: 05/27/2023]
Abstract
AIM OF THE STUDY Convolvulus pluricaulis (Convolvulaceae) has long been used as traditional herbal medicine in India as nerve tonic. We investigated neuroprotective effects of aqueous extract from Convolvulus pluricaulis (CP) against aluminium chloride induced neurotoxicity in rat cerebral cortex. MATERIAL, METHOD AND RESULT Daily administration of CP (150 mg/kg) for 3 months along with aluminium chloride (50 mg/kg) decreased the elevated enzymatic activity of acetylcholine esterase and also inhibited the decline in Na(+)/K(+)ATPase activity which resulted from aluminium intake. Beside, preventing accumulation of lipid and protein damage, changes in the levels of endogenous antioxidant enzymes associated with aluminium administration were also rectified. Oral administration of CP preserved the mRNA levels of muscarinic receptor 1 (M1 receptor), choline acetyl transferase (ChAT) and Nerve Growth Factor-Tyrosine kinase A receptor (NGF-TrkA). It also ameliorated the upregulated protein expression of cyclin dependent kinase5 (Cdk5) induced by aluminium. The potential of CPE to inhibit aluminium induced toxicity was compared with rivastigmine tartrate (1mg/kg), which was taken as standard. The potential of the extract to prevent aluminium-induced neurotoxicity was also reflected at the microscopic level, indicative of its neuroprotective effects. CONCLUSION Convolvulus pluricaulis possesses neuroprotective potential, thus validating its use in alleviating toxic effects of aluminium.
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Affiliation(s)
- Syed Waseem Bihaqi
- Dr B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
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Shenk JC, Liu J, Fischbach K, Xu K, Puchowicz M, Obrenovich ME, Gasimov E, Alvarez LM, Ames BN, Lamanna JC, Aliev G. The effect of acetyl-L-carnitine and R-alpha-lipoic acid treatment in ApoE4 mouse as a model of human Alzheimer's disease. J Neurol Sci 2009; 283:199-206. [PMID: 19342064 DOI: 10.1016/j.jns.2009.03.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We measured age-dependent effects of human ApoE4 on cerebral blood flow (CBF) using ApoE4 transgenic mice compared to age-matched wild-type (WT) mice by use of [(14)C] iodoantipyrene autoradiography. ApoE4 associated factors reduce CBF gradually to create brain hypoperfusion when compared to WT, and the differences in CBF are greatest as animals age from 6-weeks to 12-months. Transmission electron microscopy with colloidal gold immunocytochemistry showed structural damage in young and aged microvessel endothelium of ApoE4 animals extended to the cytoplasm of perivascular cells, perivascular nerve terminals and hippocampal neurons and glial cells. These abnormalities coexist with mitochondrial structural alteration and mitochondrial DNA overproliferation and/or deletion in all brain cellular compartments. Spatial memory and temporal memory tests showed a trend in improving cognitive function in ApoE4 mice fed selective mitochondrial antioxidants acetyl-l-carnitine and R-alpha-lipoic acid. Our findings indicate that ApoE4 genotype-induced mitochondrial changes and associated structural damage may explain age-dependent pathology seen in AD, indicating potential for novel treatment strategies in the near future.
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Affiliation(s)
- Justin C Shenk
- Department of Biology and Electron Microscopy Research Center, University of Texas at San Antonio, San Antonio, TX 78249, USA
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Miasnikov AA, Chen JC, Weinberger NM. Behavioral memory induced by stimulation of the nucleus basalis: effects of contingency reversal. Neurobiol Learn Mem 2009; 91:298-309. [PMID: 19168141 PMCID: PMC2896312 DOI: 10.1016/j.nlm.2008.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/27/2008] [Accepted: 12/24/2008] [Indexed: 11/18/2022]
Abstract
Specific behavioral associative memory induced by stimulation of the cortically-projecting cholinergic nucleus basalis (NB) is dependent on intrinsic acetylcholine and shares with natural memory such features as associativity, specificity, rapid formation, consolidation and long-term retention. Herein, we examined extinction and the effects of stimulus pre-exposure. Two groups of adult male rats (n=4 each) were first tested for behavioral responses (disruption of ongoing respiration) to tones (1-15 kHz), constituting a pre-training behavioral frequency generalization gradient (BFGG). They next received a first session of training, 200 trials of a tone (8.00 kHz, 70 dB, 2 s) either paired with electrical stimulation of the NB (100 Hz, 0.2 s, approximately 67 microA, NBstm) (group IP) or unpaired (group IU). Twenty-four hours later, they were tested for behavioral memory by obtaining post-training BFGGs. Then the contingencies were reversed yet another 24 h later; the IP group received tone and NBstm unpaired and the IU group received them paired. A final set of generalization gradients was obtained the next day. All stimuli were presented with subjects under state control indexed by regular respiration. Tested 24 h post-initial training, the IP group developed specific associative behavioral memory indicated by increased responses only to CS-band frequencies, while the IU group did not. After subsequent training with unpaired stimuli, the IP group exhibited experimental extinction. Furthermore, after initial exposure to the CS and NBstm unpaired, the IU group exhibited a tendency toward reduced conditioning to CS/NBstm pairing and a significant increase in latency of conditioned responses. The present findings provide additional support for the hypothesis that engagement of the NB is sufficient to induce natural associative memory and suggest that activation of the NB may be a normal component in the formation of natural associative memory.
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Affiliation(s)
- Alexandre A. Miasnikov
- Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, United States
| | - Jemmy C. Chen
- Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, United States
| | - Norman M. Weinberger
- Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, United States
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Siegel JA, Benice TS, Van Meer P, Park BS, Raber J. Acetylcholine receptor and behavioral deficits in mice lacking apolipoprotein E. Neurobiol Aging 2009; 32:75-84. [PMID: 19178986 DOI: 10.1016/j.neurobiolaging.2008.12.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 11/11/2008] [Accepted: 12/09/2008] [Indexed: 12/01/2022]
Abstract
Apolipoprotein E (apoE) is involved in the risk to develop sporadic Alzheimer's disease (AD). Since impaired central acetylcholine (ACh) function is a hallmark of AD, apoE may influence ACh function by modulating muscarinic ACh receptors (mAChRs). To test this hypothesis, mAChR binding was measured in mice lacking apoE and wild type C57BL/6J mice. Mice were also tested on the pre-pulse inhibition, delay eyeblink classical conditioning, and 5-choice serial reaction time tasks (5-SRTT), which are all modulated by ACh transmission. Mice were also given scopolamine to challenge central mAChR function. Compared to wild type mice, mice lacking apoE had reduced number of cortical and hippocampal mAChRs. Scopolamine had a small effect on delay eyeblink classical conditioning in wild type mice but a large effect in mice lacking apoE. Mice lacking apoE were also unable to acquire performance on the 5-SRTT. These results support a role for apoE in ACh function and suggest that modulation of cortical and hippocampal mAChRs might contribute to genotype differences in scopolamine sensitivity and task acquisition. Impaired apoE functioning may result in cholinergic deficits that contribute to the cognitive impairments seen in AD.
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Affiliation(s)
- Jessica A Siegel
- Department of Behavioral Neuroscience, Oregon Health & Science University, 8131 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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Abstract
It is widely accepted that cholinergic activity at muscarinic receptors is required to maintain cognitive functions, including learning and memory. Memory domains are especially impaired in schizophrenia, which may explain difficulties in psychosocial rehabilitation of individuals with this illness. However, little is known about the mechanism of this impairment. To understand our current knowledge, we reviewed the literature since 1990 via a PubMed search for the terms "muscarinic", "schizophrenia", "cognition", "memory", "learning", and "agonist" in combination. We found 89 basic science/laboratory studies, case reports/series, case-control studies, cross-sectional studies, standardized controlled animal trials, standardized controlled human trials, and reviews. Although further research is required to fully understand the neuropharmacology of the cholinergic system in cognitive function in schizophrenia, we have examined the data currently available. In general, these data suggest that agonist activity at acetylcholine muscarinic type 1 (M1) receptors would enhance memory and learning in schizophrenia. We present an overview of likely side effects of muscarinic agonists. We outline the anticholinergic activity of several available antipsychotics and review the available M1 muscarinic agonists.
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Miasnikov AA, Chen JC, Weinberger NM. Specific auditory memory induced by nucleus basalis stimulation depends on intrinsic acetylcholine. Neurobiol Learn Mem 2008; 90:443-54. [PMID: 18573347 PMCID: PMC2556567 DOI: 10.1016/j.nlm.2008.05.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/23/2008] [Accepted: 05/27/2008] [Indexed: 10/21/2022]
Abstract
Although the cholinergic system has long been implicated in the formation of memory, there had been no direct demonstration that activation of this system can actually induce specific behavioral memory. We have evaluated the "cholinergic-memory" hypothesis by pairing a tone with stimulation of the nucleus basalis (NB), which provides acetylcholine to the cerebral cortex. We found that such pairing induces behaviorally-validated auditory memory. NB-induced memory has the key features of natural memory: it is associative, highly-specific and rapidly induced. Moreover, the level of NB stimulation controls the amount of detail in memory about the tonal conditioned stimulus. While consistent with the hypothesis that properly-timed release of acetylcholine (ACh) during natural learning is sufficient to induce memory, pharmacological evidence has been lacking. This study asked whether scopolamine, a muscarinic antagonist, impairs or prevents the formation of NB-induced memory. Adult male rats were first tested for responses (disruption of ongoing respiration) to tones (1-15 kHz), constituting a pre-training behavioral frequency generalization gradient (BFGG). Then, they received a single session of 200 trials of a tone (8.00 kHz, 70 dB, 2 s) paired with electrical stimulation of the NB (100 Hz, 0.2 s). Immediately after training, they received either scopolamine (1.0 mg/kg, i.p.) or saline. Twenty-four hours later, they were tested for specific memory by obtaining post-training BFGGs. The saline group developed CS-specific memory, manifested by maximum increase in response specific to the CS frequency band. In contrast, the scopolamine group exhibited no such memory. These findings indicate that NB-induced specific associative behavioral memory requires the action of intrinsic acetylcholine at muscarinic receptors, and supports the hypothesis that natural memory formation engages the nucleus basalis and muscarinic receptors.
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Affiliation(s)
- Alexandre A Miasnikov
- Center for the Neurobiology of Learning and Memory, 309 Qureshey Research Laboratory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, USA
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Blokland A, Boess F. Use of behavioural and long-term potentiation models in the development of memory-improving drugs. Expert Opin Drug Discov 2008; 3:1067-80. [DOI: 10.1517/17460441.3.9.1067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Veinbergs I, Mallory M, Sagara Y, Masliah E. Vitamin E supplementation prevents spatial learning deficits and dendritic alterations in aged apolipoproteinE-deficient mice. Eur J Neurosci 2008. [DOI: 10.1111/j.1460-9568.2000.01308.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Miasnikov AA, Chen JC, Gross N, Poytress BS, Weinberger NM. Motivationally neutral stimulation of the nucleus basalis induces specific behavioral memory. Neurobiol Learn Mem 2008; 90:125-37. [PMID: 18343695 PMCID: PMC2496874 DOI: 10.1016/j.nlm.2008.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 02/05/2008] [Accepted: 02/05/2008] [Indexed: 11/28/2022]
Abstract
The cholinergic system has been implicated in learning and memory. The nucleus basalis (NB) provides acetylcholine (ACh) to the cerebral cortex. Pairing a tone with NB stimulation (NBstm) to alter cortical state induces both associative specific tuning plasticity in the primary auditory cortex (A1) and associative specific auditory behavioral memory. NB-induced memory has major features of natural memory that is induced by pairing a tone with motivational reinforcers, e.g., food or shock, suggesting that the cholinergic system may be a "final common pathway" whose activation promotes memory storage. Alternatively, NB stimulation might itself be motivationally significant, either rewarding or punishing. To investigate these alternatives, adult male rats (n=7) first formed a specific NB-induced memory (CS=8.0kHz, 2.0s paired with NBstm, ISI=1.8s, 200 trials), validated by post-training (24h) frequency generalization gradients (1-15kHz) of respiration interruption that were specific to the CS frequency. Thereafter, they received the same level of NBstm that had induced memory, while confined to one quadrant of an arena, and later tested for place-preference, i.e., avoidance or seeking of the quadrant of NBstm. This NBstm group exhibited neither preference for nor against the stimulated quadrant, compared to sham-operated subjects (n=7). The findings indicate that specific associative memory can be induced by direct activation of the NB without detectable motivational effects of NB stimulation. These results are concordant with a memory-promoting role for the nucleus basalis that places it "downstream" of motivational systems, which activate it to initiate the storage of the current state of its cholinergic targets.
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Affiliation(s)
- Alexandre A Miasnikov
- Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800, USA
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McDonald SR, Forster MJ. Lifelong vitamin E intake retards age-associated decline of spatial learning ability in apoE-deficient mice. AGE (DORDRECHT, NETHERLANDS) 2005; 27:5-16. [PMID: 23598599 PMCID: PMC3456095 DOI: 10.1007/s11357-005-4003-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Accepted: 03/11/2005] [Indexed: 05/08/2023]
Abstract
The potential for lifelong vitamin E supplementation to delay age-associated cognitive decline was tested in apoE-deficient and wild-type C57BL/6 mice. Beginning at eight weeks of age, the mice were maintained on a control diet or diets supplemented with dl-α-tocopheryl acetate yielding approximate daily intakes of either 20 or 200 mg/kg body weight. When 6 or 18 months of age, cognitive functioning of the mice was assessed using swim maze and discriminated avoidance testing procedures. For the mice maintained on control diets, the age-related declines in swim maze performance were relatively larger in apoE-deficient mice when compared with wild-type. On the other hand, age-associated declines in learning and working memory for discriminated avoidance were similar in the two genotypes. The 200-mg/kg dose of vitamin E prevented the accelerated decline in spatial learning apparent in 18-month-old apoE-deficient mice, but had no equivalent effect on performance declines attributable to normal aging in the wild-type mice. Vitamin E supplementation failed to prevent age-related impairments in learning and memory for discriminated avoidance observed in both the wild-type and apoE-deficient mice. The current findings are consistent with the hypothesis that apoE deficiency confers an accelerated, though probably selective, loss of brain function with age. This loss of function would appear to involve pathogenic oxidative mechanisms that can be prevented or offset by antioxidant supplementation.
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Affiliation(s)
- Shelley R. McDonald
- Department of Pharmacology and Neuroscience and Institute for Aging and Alzheimer’s Disease Research, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107 USA
| | - Michael J. Forster
- Department of Pharmacology and Neuroscience and Institute for Aging and Alzheimer’s Disease Research, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107 USA
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107 USA
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20
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Everett AW, Ernst EJ. Increased quantal size in transmission at slow but not fast neuromuscular synapses of apolipoprotein E deficient mice. Exp Neurol 2004; 185:290-6. [PMID: 14736510 DOI: 10.1016/j.expneurol.2003.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Uncertainties from the literature concerning the role of apolipoprotein E (apoE) in central cholinergic function prompted us to investigate what effect apoE may have on transmission at the neuromuscular junction. Both spontaneous and evoked release were measured in isolated extensor digitorum longus (edl) and soleus muscles from both wild-type and apoE-deficient mice. Miniature endplate and nerve-evoked endplate potentials (MEPPs and EPPs, respectively) were indistinguishable in edl muscles in both groups of mice; however, MEPP amplitudes in soleus muscles were significantly larger (by an average of 23%) in apoE-deficient mice compared with 5- to 7-week-old age-matched wild-type mice. The EPP amplitudes were also larger in soleus muscles in the mutant mice, but this was a reflection of the larger quantal size in this muscle because quantal content, determined from the ratio of the average EPP amplitude to average MEPP amplitude, was unchanged from normal in the mutant mice. The MEPP frequency and the percent of nerve stimulations failing to produce an EPP were unchanged from normal in both muscle types in the mutant mice. The difference in quantal size in soleus muscle transmission between mutant and wild-type mice was abolished in the presence of neostigmine, an acetylcholinesterase inhibitor. The results suggest that apoE normally associates with acetylcholinesterase in the synaptic cleft of slow muscles, modulating the activity of the enzyme and therefore quantal size.
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Affiliation(s)
- A W Everett
- Physiology, M311, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley 6009, Australia.
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21
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Experience-Dependent Response Plasticity in the Auditory Cortex: Issues, Characteristics, Mechanisms, and Functions. PLASTICITY OF THE AUDITORY SYSTEM 2004. [DOI: 10.1007/978-1-4757-4219-0_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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22
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Fisher A, Brandeis R, Haring R, Bar-Ner N, Kliger-Spatz M, Natan N, Sonego H, Marcovitch I, Pittel Z. Impact of muscarinic agonists for successful therapy of Alzheimer's disease. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2003:189-202. [PMID: 12456063 DOI: 10.1007/978-3-7091-6139-5_18] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
The M1 muscarinic agonists AF102B, AF150(S) & AF267B--i) restored cognitive impairments in several animal models for AD with an excellent safety margin; ii) elevated alpha-APPs levels; iii) attenuated vicious cycles induced by A beta, and inhibited A beta- and oxidative stress-induced apoptosis; and iv) decreased tau hyperphosphorylation. AF150(S) and AF267B were more effectve than rivastigmine and nicotine in restoring memory impairments in mice with small hippocampi. In apolipoprotein E-knockout mice, AF150(S) restored cognitive impairments and cholinergic hypofunction and decreased tau hyperphosphorylation. In aged microcebes, AF150(S) restored cognitive and behavioral impairments and decreased tau hyperphosphorylation, paired helical filaments and astrogliosis. In rabbits, AF267B & AF150(S) decreased CSF A beta(1-42 & 1-40), while AF102B reduced A beta(1-40). Finally AF102B decreased CSF A beta(total) in AD patients. Taken together, M1 agonists may represent a unique therapy in AD due to their beneficial effects on three major hallmarks of AD--cholinergic hypofunction, A beta and tau protein hyperphosphorylation.
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Affiliation(s)
- A Fisher
- Israel Institute for Biological Research, Ness-Ziona, Israel.
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23
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Champagne D, Dupuy JB, Rochford J, Poirier J. Apolipoprotein E knockout mice display procedural deficits in the Morris water maze: analysis of learning strategies in three versions of the task. Neuroscience 2002; 114:641-54. [PMID: 12220566 DOI: 10.1016/s0306-4522(02)00313-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Apolipoprotein E knockout (apoEKO) mice have been shown to be impaired in the spatial Morris water maze (MWM). However, several groups failed to replicate this finding. One reason for this inconsistency may stem from variations in the experimental protocols and environment between laboratories. In the present study, we have tested if age and variations in protocol implementation that specifically affect salience of the visual extramaze cues influence performance and navigational strategies in the MWM. We tested three- and 12-month-old apoEKO and wild type mice in three versions of the MWM differing on the availability of visual extramaze cues: (1) salient cues, (2) diffuse cues, and (3) absence of cues. Our results show that the presence of salient cues enhances acquisition performance of wild type, but not apoEKO mice in the MWM. This effect was restricted to the acquisition phase since apoEKO mice reached a level of performance that was comparable to that of controls toward the end of the task. No significant differences were detected between apoEKO and controls in either the diffuse cues or absence of cues paradigms. Thigmotaxic tendencies were observed in apoEKO mice and correlated high latency scores. Thigmotaxis may have interfered with the initial ability to engage in a proficient navigational strategy. These findings suggest that, in contrast to what has been proposed in the past, apoEKO mice appear not to be impaired in spatial memory per se but are deficient in a procedural component of the MWM. Furthermore, the procedural deficit and corresponding thigmotaxic tendencies of apoEKO mice appeared to increase with age. Taken together, these findings confirm our hypothesis that age and variations in experimental protocols can influence MWM performances.
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Affiliation(s)
- D Champagne
- Douglas Hospital Research Centre, Department of Neurology and Neurosurgery, McGill University, Verdun, QC, Canada
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Parasuraman R, Greenwood PM, Sunderland T. The apolipoprotein E gene, attention, and brain function. Neuropsychology 2002. [PMID: 11949718 DOI: 10.1037//0894-4105.16.2.254] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The epsilon4 allele of the apolipoprotein E (ApoE) gene is associated with alterations in brain function and is a risk factor for Alzheimer's disease (AD). Changes in components of visuospatial attention with ApoE-epsilon4, aging, and AD are described. Healthy middle-aged adults without dementia who have the ApoE-epsilon4 gene show deficits in spatial attention and working memory that are qualitatively similar to those seen in clinically diagnosed AD patients. The findings support an association between ApoE polymorphism and specific components of visuospatial attention. Molecular mechanisms that may mediate the ApoE-attention link by modulating cholinergic neurotransmission to the posterior parietal cortex are discussed. Studies of attention and brain function in ApoE-epsilon4 carriers without dementia can advance knowledge of the genetics of visual attention, may enhance understanding of the preclinical phase of AD, and may lead to better methods for early AD detection.
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Affiliation(s)
- Raja Parasuraman
- Cognitive Science Laboratory, Catholic University of America, Washington, DC 20064, USA.
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25
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Lin K, Wang D, Sadée W. Serum response factor activation by muscarinic receptors via RhoA. Novel pathway specific to M1 subtype involving calmodulin, calcineurin, and Pyk2. J Biol Chem 2002; 277:40789-98. [PMID: 12200418 DOI: 10.1074/jbc.m202745200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The muscarinic cholinergic receptor (mAChR) subtypes share high sequence similarity except in their third intracellular loop and COOH terminus, domains thought to be involved in signal transduction. Subtypes M1, M3, and M5 couple mainly through Galpha(q/11), and M2 and M4 couple mainly through Galpha(i/o). Whether subtypes within each of these two groups differ in their signaling pathways remains to be resolved. This study focused on nuclear signaling pathways leading to activation of the transcription factor, serum response factor (SRF). Genes encoding M1, M2, and M3 were co-expressed in Jurkat T lymphocytes with a reporter gene driven by a mutant serum response element, SRE.L, which responds to SRF activation. We show that only M1 mAChR activated SRF through a pathway involving the small GTPase RhoA, with no response observed for M2 and M3. Transfection of GTPase-deficient Galpha subunits (GalphaQL; constitutively active form) demonstrated that SRF was activated by Galpha(13)QL but only marginally by Galpha(q)QL and Galpha(12)QL in Jurkat cells. Yet transfection of regulator of G protein-signaling protein, RGS2 and RGS4, which inhibit Galpha(q/11) activity, indicated that Galpha(q/11) and Ca(2+) mobilization were required for SRF activation by M1. Calmodulin inhibitors suppressed the M1 and the Galpha(13)QL pathways, acting both upstream and downstream of RhoA. However, calcineurin inhibitors and the tyrosine kinase inhibitor genistein selectively suppressed SRF activation by M1, but not by Galpha(13)QL, indicating the presence of separate pathways. The calmodulin-dependent tyrosine kinase Pyk2 was also activated by M1 but not M3, and Pyk2 appears also to play a role in M1-SRF activation, as judged by experiments with two dominant-negative Pyk2 mutants. These results reveal a novel calmodulin-dependent RhoA-SRF signaling pathway unique to the M1 mAChR subtype.
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Affiliation(s)
- Kedan Lin
- Departments of Biopharmaceutical Sciences and Pharmaceutical Chemistry, University of California, San Francisco, CA 94143-0446, USA
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26
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Fodero LR, Small DH. Cholinergic abnormalities in Alzheimer's disease: are there new targets for drug development? Drug Dev Res 2002. [DOI: 10.1002/ddr.10089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Vesey R, Birrell JM, Bolton C, Chipperfield RS, Blackwell AD, Dening TR, Sahakian BJ. Cholinergic nicotinic systems in Alzheimer's disease: prospects for pharmacological intervention. CNS Drugs 2002; 16:485-500. [PMID: 12056923 DOI: 10.2165/00023210-200216070-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Within the last few years, research into the cause and progression of Alzheimer's disease has made significant advances. Although there is still no preventative treatment or cure for this neurodegenerative illness, the development of drugs that may alleviate some of the cognitive symptoms associated with it is advancing. Cholinesterase inhibitors are at present the most effective form of treatment and have shown significant overall response rates in clinical trials. However, although some patients show substantial improvement when treated with this class of drugs, there is considerable variability in the amount of benefit gained in different individuals in terms of their cognitive and behavioural functioning. Furthermore, unfortunately some patients gain little or no benefit from these drugs. It would therefore be of great advantage to explore alternative therapeutic possibilities. This article reviews the potential involvement of the nicotinic cholinergic system in Alzheimer's disease and discusses the possibility of nicotinic pharmacotherapy. Substantial evidence indicates the involvement of the nicotinic cholinergic system in the pathology of Alzheimer's disease. Drugs targeting these sites may not only have a positive effect on cognitive function, but also have additional therapeutic benefits in terms of restoring the hypoactivity in the excitatory amino acid pyramidal system and even slowing the emergence of Alzheimer's disease pathology. The conclusion of this review is that nicotinic treatments are an important potential source of new therapeutic interventions in Alzheimer's disease.
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Affiliation(s)
- Robyn Vesey
- Department of Psychiatry, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge, UK
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28
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Fisher A, Brandeis R, Bar-Ner RHN, Kliger-Spatz M, Natan N, Sonego H, Marcovitch I, Pittel Z. AF150(S) and AF267B: M1 muscarinic agonists as innovative therapies for Alzheimer's disease. J Mol Neurosci 2002; 19:145-53. [PMID: 12212772 DOI: 10.1007/s12031-002-0025-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The M1 muscarinic agonists AF102B (Cevimeline, EVOXACTM: prescribed in USA and Japan for Sjogren's Syndrome), AF150(S) and AF267B--1) are neurotrophic and synergistic with neurotrophins such as nerve growth factor and epidermal growth factor; 2) elevate the non-amyloidogenic amyloid precursor protein (alpha-APPs) in vitro and decrease beta-amyloid (A beta) levels in vitro and in vivo; and 3) inhibit A beta- and oxidative-stress-induced cell death and apoptosis in PC12 cells transfected with the M1 muscarinic receptor. These effects can be combined with the beneficial effects of these compounds on some other major hallmarks of Alzheimer's disease (AD) (e.g. tau hyperphosphorylation and paired helical filaments [PHF]; and loss of cholinergic function conducive to cognitive impairments.) These drugs restored cognitive impairments in several animal models for AD, mimicking different aspects of AD, with a high safety margin (e.g. AF150[S] >1500 and AF267B >4500). Notably, these compounds show a high bioavailability and a remarkable preference for the brain vs. plasma following p.o. administration. In mice with small hippocampi, unlike rivastigmine and nicotine, AF150(S) and AF267B restored cognitive impairments also on escape latency in a Morris water maze paradigm in reversal learning. Furthermore, in aged and cognitively impaired microcebes (a natural animal model that mimics AD pathology and cognitive impairments), prolonged treatment with AF150(S) restored cognitive and behavioral impairments and decreased tau hyperphosphorylation, PHF and astrogliosis. Our M1 agonists, alone or in polypharmacy, may present a unique therapy in AD due to their beneficial effects on major hallmarks of AD.
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29
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Parasuraman R, Greenwood PM, Sunderland T. The apolipoprotein E gene, attention, and brain function. Neuropsychology 2002; 16:254-74. [PMID: 11949718 PMCID: PMC1350934 DOI: 10.1037/0894-4105.16.2.254] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The epsilon4 allele of the apolipoprotein E (ApoE) gene is associated with alterations in brain function and is a risk factor for Alzheimer's disease (AD). Changes in components of visuospatial attention with ApoE-epsilon4, aging, and AD are described. Healthy middle-aged adults without dementia who have the ApoE-epsilon4 gene show deficits in spatial attention and working memory that are qualitatively similar to those seen in clinically diagnosed AD patients. The findings support an association between ApoE polymorphism and specific components of visuospatial attention. Molecular mechanisms that may mediate the ApoE-attention link by modulating cholinergic neurotransmission to the posterior parietal cortex are discussed. Studies of attention and brain function in ApoE-epsilon4 carriers without dementia can advance knowledge of the genetics of visual attention, may enhance understanding of the preclinical phase of AD, and may lead to better methods for early AD detection.
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Affiliation(s)
- Raja Parasuraman
- Cognitive Science Laboratory, Catholic University of America, Washington, DC 20064, USA.
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30
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Grootendorst J, de Kloet ER, Dalm S, Oitzl MS. Reversal of cognitive deficit of apolipoprotein E knockout mice after repeated exposure to a common environmental experience. Neuroscience 2002; 108:237-47. [PMID: 11734357 DOI: 10.1016/s0306-4522(01)00412-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study tests the hypothesis that a history of common stressful experiences further promotes the cognitive deficit of apolipoprotein E (apoE)-knockout mice, an animal model to study aspects of Alzheimer's disease. In experiment 1, apoE-knockout and wild-type mice were repeatedly subjected to an environmental challenge (i.e. exposure to rats) and the effect was monitored on Morris water maze performance. Naive apoE-knockout mice were impaired, but surprisingly after rat stress their water maze performance improved and switched to a goal-directed search strategy. Rat stress induced in wild-type mice spatial learning deficits and an inefficient search strategy. Swim ability was not affected by rat stress and under basal conditions measures for locomotion and anxiety were similar for both genotypes. In experiments 2 and 3, we found that the rat stress paradigm attenuated the elevation of basal and stress-induced corticosterone concentrations in the apoE-knockout mice towards concentrations observed in wild-type mice. The expression of hippocampal mineralocorticoid and glucocorticoid receptor mRNA was similar in both genotypes, but in response to rat stress, the level of glucocorticoid receptor mRNA increased selectively in the CA1 pyramidal field. In conclusion, repeated exposure to a common environmental experience did abolish and reverse the difference in cognitive performance and corticosterone concentrations of apoE-knockout and wild-type mice.
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MESH Headings
- Adrenal Cortex Hormones/blood
- Alzheimer Disease/metabolism
- Alzheimer Disease/pathology
- Alzheimer Disease/physiopathology
- Animals
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Behavior, Animal/physiology
- Cognition Disorders/genetics
- Cognition Disorders/metabolism
- Conditioning, Psychological/physiology
- Environment, Controlled
- Female
- Glucocorticoids/blood
- Hippocampus/metabolism
- Hippocampus/pathology
- Hippocampus/physiopathology
- Male
- Maze Learning/physiology
- Mice
- Mice, Knockout
- Mineralocorticoids/blood
- Neurons/metabolism
- Neurons/pathology
- RNA, Messenger/metabolism
- Rats
- Receptors, Steroid/genetics
- Receptors, Steroid/metabolism
- Recovery of Function/genetics
- Stress, Physiological/genetics
- Stress, Physiological/metabolism
- Stress, Physiological/pathology
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Affiliation(s)
- J Grootendorst
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research and Leiden University Medical Centre, University of Leiden, P.O. Box 9503, 2300 RA Leiden, The Netherlands
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Fein A, Magid N, Savion S, Orenstein H, Shepshelovich J, Ornoy A, Torchinsky A, Toder V. Diabetes teratogenicity in mice is accompanied with distorted expression of TGF-beta2 in the uterus. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 2002; 22:59-71. [PMID: 11754388 DOI: 10.1002/tcm.1039] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Early embryonic deaths as well as malformed newborns are among complications of the diabetic pregnancy. Cytokines and growth factors operating in the embryonic vicinity are found to be among factors that determine the sensitivity of embryos to external and internal detrimental stimuli, including diabetes. Transforming Growth Factor-beta2 (TGF-beta2) has been shown to be essential for embryonic development and survival. In the present work, we evaluated the pattern of TGF-beta2 expression in the uterus of streptozotocin-induced diabetic mice, demonstrating a decreased reproductive performance and elevated percentage of litters with severely malformed fetuses. Since stimulation of the maternal immune system was found to increase the resistance of mouse embryos to the teratogenic effect of diabetes, the effect of immunopotentiation on the expression of the cytokine was also investigated. TGF-beta2 expression was studied at the mRNA level by using the in situ hybridization technique and at the protein level by using the immunohistochemical analysis. A clear decrease in TGF-beta2 mRNA expression in the uterus of diabetic mice was observed at examined time points: days 1, 5, and 9 of pregnancy. Also, an evident reduction in TGF-beta2, the protein expression in the uterus of diabetic mice, was demonstrated at these time points. Maternal immunopotentiation that improved the reproductive performance of diabetic mice and reduced the number of the litters with malformed fetuses was also accompanied by a clear increase in the level of TGF-beta2 mRNA expression in the pregnant uteri. The above results clearly demonstrate that the embryotoxic effect of diabetes is accompanied by an alteration of TGF-beta2 expression. Immunopotentiation that was shown to improve the reproductive performance of the diabetic mice was accompanied by a partial normalization of TGF-beta2 expression in embryonic vicinity.
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Affiliation(s)
- A Fein
- Department of Embryology and Teratology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Ikonen S, Tanila H. Effects of metrifonate on the hippocampal theta rhythm of freely moving intact and MS-lesioned mice. Pharmacol Biochem Behav 2001; 69:165-72. [PMID: 11420082 DOI: 10.1016/s0091-3057(01)00495-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Changes in hippocampal electroencephalogram (EEG) have been suggested to be closely associated with spatial learning ability. Spatial learning can be improved in medial septal (MS)-lesioned mice by metrifonate, a cholinesterase inhibitor. We designed this study to investigate the effects of metrifonate on the hippocampal theta oscillation of intact and MS-lesioned mice. Intact and MS-lesioned C57BL mice were treated with acute injections of metrifonate (doses: 15, 50 and 100 mg/kg ip). These included a dose that considerably improved spatial memory of MS-lesioned mice in our earlier study. In addition, subtype selective muscarinic agents, BIBN-99, AF267B and AF150(S) were used. Recordings of hippocampal theta during movement and awake immobility revealed a dramatic reduction of theta in the lesioned animals. Metrifonate induced prominent changes in the EEG of intact mice, but not of MS-lesioned mice. The effect of metrifonate was not mimicked by two selective M(1)-agonists and was augmented by a combined injection of a selective M(2)-antagonist. These data suggest that improved spatial learning by the cholinesterase inhibitor metrifonate is unrelated to its effects on the hippocampal EEG. These two effects may be mediated through different muscarinic receptor subtypes.
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Affiliation(s)
- S Ikonen
- Department of Neuroscience and Neurology and the University Hospital, University of Kuopio, P.O. Box 1627, 70211, Kuopio, Finland
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Fisher A, Michaelson DM, Brandeis R, Haring R, Chapman S, Pittel Z. M1 muscarinic agonists as potential disease-modifying agents in Alzheimer's disease. Rationale and perspectives. Ann N Y Acad Sci 2001; 920:315-20. [PMID: 11193170 DOI: 10.1111/j.1749-6632.2000.tb06941.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A cholinergic hypofunction in Alzheimer's disease (AD) may lead to formation of beta-amyloids that might impair the coupling of M1 muscarinic ACh receptors (mAChRs) with G proteins. This disruption in coupling can lead to decreased signal transduction, to a reduction in levels of trophic amyloid precursor proteins (APPs), and to generation of more beta-amyloids that can also suppress ACh synthesis and release, aggravating further the cholinergic deficiency. These "vicious cycles," a presynaptic and a postsynaptic one, may be inhibited, in principle, by M1 selective agonists. Such properties can be detected in the functionally selective M1 agonists from the AF series [e.g., project drugs, AF102B, AF150(S)]. These M1 agonists promote the nonamyloidogenic APP processing pathways and decrease tau protein phosphorylation. The effects on tau proteins suggest a link between M1 mAChR-mediated signal transduction system(s) and the neuronal cytoskeleton via regulation of phosphorylation of tau microtubule-associated protein. This may indicate a dual role for M1 agonists: as inhibitors of two "vicious cycles," one induced by beta-amyloids, and the other due to overactivation of certain kinases (e.g., glycogen synthase kinase-3, GSK-3) or downregulation of phosphatases, respectively. Prolonged administration of AF150(S) in apolipoprotein E-knockout mice restored cognitive impairments, cholinergic hypofunction, and tau hyperphosphorylation, and unveiled a high-affinity binding site to M1 mAChRs. Except M1 agonists, there are no reports of compounds having such combined effects, for example, amelioration of cognition dysfunction and beneficial modulation of APPs together with tau phosphorylation. This unique property of M1 agonists to alter different aspects of AD pathogenesis could represent the most remarkable, yet unexplored, clinical value of such compounds.
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Affiliation(s)
- A Fisher
- Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100, Israel.
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34
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Veinbergs I, Mallory M, Sagara Y, Masliah E. Vitamin E supplementation prevents spatial learning deficits and dendritic alterations in aged apolipoproteinE-deficient mice. Eur J Neurosci 2000. [DOI: 10.1046/j.1460-9568.2000.01308.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Iwata N, Kozuka M, Hara T, Kanek T, Tonohiro T, Sugimoto M, Niitsu Y, Kondo Y, Yamamoto T, Sakai J, Nagano M. Activation of cerebral function by CS-932, a functionally selective M1 partial agonist: neurochemical characterization and pharmacological studies. JAPANESE JOURNAL OF PHARMACOLOGY 2000; 84:266-80. [PMID: 11138727 DOI: 10.1254/jjp.84.266] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A newly synthesized agonist for muscarinic acetylcholine (ACh) receptors CS-932, (R)-3-(3-iso-xazoloxy)-1-azabicyclo-[2.2.2]octane hydrochloride, showed a relatively higher affinity for M1 than M2 receptors expressed in Chinese hamster ovary (CHO)-cells in comparison with ACh. CS-932 elevated the intracellular Ca2+ level only in M1-CHO cells, although ACh increased the level in both M1- and M3-CHO cells. CS-932 and ACh reduced forskolin-stimulated accumulation of cAMP in M2-CHO cells by 20% and 80%, respectively. This neurochemical profile of CS-932 indicates that the compound can activate M1-receptor-mediated functions selectively. CS-932 increased firing of cholinoceptive neurons in rat hippocampal slices, and this excitation was antagonized by pirenzepine, but not by AF-DX 116. CS-932 increased awake and decreased slow wave sleep episodes of daytime EEG in free-moving rats. It counteracted scopolamine-induced slow waves in rat cortical EEG. CS-932 also increased the power of alpha- and beta-waves, but decreased delta-wave of the cortical EEG in anesthetized monkeys. It ameliorated scopolamine-induced impairment of working memory in rats. Orally administered CS-932 had the best penetration into the brain among the muscarinic agonists tested and caused the least salivary secretion among the cholinomimetics examined. These results indicate that CS-932 has potential as a cognitive enhancer with fewer side effects in therapy for Alzheimer disease.
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Affiliation(s)
- N Iwata
- Neuroscience and Immunology Research Laboratories, Sankyo Co., Ltd., Tokyo, Japan
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Greenwood PM, Sunderland T, Friz JL, Parasuraman R. Genetics and visual attention: selective deficits in healthy adult carriers of the epsilon 4 allele of the apolipoprotein E gene. Proc Natl Acad Sci U S A 2000; 97:11661-6. [PMID: 11027364 PMCID: PMC17257 DOI: 10.1073/pnas.97.21.11661] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2000] [Indexed: 11/18/2022] Open
Abstract
The epsilon4 allele of the apolipoprotein E (APOE) gene is associated with altered brain physiology in healthy adults before old age, but concomitant deficits in cognition on standardized tests of cognitive function have not been consistently demonstrated. We hypothesized that sensitive and specific assessment of basic attentional functions that underlie complex cognition would reveal evidence of impairment in otherwise asymptomatic individuals. We found that as early as middle age, nondemented carriers of the varepsilon4 allele of the APOE gene showed deficits when visual attention was spatially directed by cues in tasks of visual discrimination and visual search, in comparison to those without the epsilon4 allele (epsilon2 and epsilon3 carriers). Two component attentional operations were selectively affected: (i) shifting spatial attention following invalid location cues, and (ii) adjusting the spatial scale of attention during visual search. These changes occurred only in the presence of the epsilon4 allele and without decline in other aspects of attention (vigilance), memory, or general cognition. The results show that specific components of visual attention are affected by APOE genotype and that the course of cognitive aging is subject to selective alteration by a genetic trait.
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Affiliation(s)
- P M Greenwood
- Cognitive Science Laboratory, Catholic University of America, Washington, DC 20064, USA
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Fisher A. Therapeutic strategies in Alzheimer's disease: M1 muscarinic agonists. JAPANESE JOURNAL OF PHARMACOLOGY 2000; 84:101-12. [PMID: 11128032 DOI: 10.1254/jjp.84.101] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The cholinergic hypofunction in Alzheimer's disease (AD) appears to be linked with two other major hallmarks of this disease, beta-amyloid and hyperphosphorylated tau protein. Formation of beta-amyloids might impair the coupling of M1 muscarinic acetylcholine receptors (mAChR) with G-proteins. This can lead to decreased signal transduction, a decrease of trophic and non-amyloidogenic amyloid precursor protein (APPs) and generation of more beta-amyloids, aggravating further the cholinergic deficiency. This review is an attempt to explore the M1 mAChR regulation of beta-amyloid metabolism, tau hyperphosphorylation and cognitive functions. The therapeutic potential of M1-selective muscarinic agonists including AF102B, AF150(S), AF267B (the AF series) is evaluated and compared, when possible, with several FDA-approved acetylcholinesterase inhibitors. These M1 agonists can elevate APPs, decrease tau protein phosphorylation/hyperphosphorylation in vitro and in vivo and restore cognitive impairments in several animal models for AD. Except for the M1 agonists, no other compounds were reported yet with combined effects; e.g., amelioration of cognition dysfunction and beneficial modulation of APPs/beta-amyloid together with tau hyperphosphorylation/phosphorylation. This property of M1 agonists to alter different aspects associated with AD pathogenesis could represent the most remarkable clinical value of such drugs.
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Affiliation(s)
- A Fisher
- Israel Institute for Biological Research, Ness-Ziona.
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38
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Abstract
The treatment of Alzheimer's disease attempts to correct cholinergic deficiency in the brain. In addition to the established, but restricted, efficacy of acetylcholinesterase inhibitors, attempts are being made to develop agents which will stimulate muscarinic receptors directly. This approach is logical and was found efficacious in several animal models of the disease; however none of these agents succeeded in clinical studies. Several reasons might account for this failure, which are discussed, as well as the prospects for the future.
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Affiliation(s)
- A D Korczyn
- Sieratzki Chair of Neurology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Israel.
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Chapman S, Sabo T, Roses AD, Michaelson DM. Reversal of presynaptic deficits of apolipoprotein E-deficient mice in human apolipoprotein E transgenic mice. Neuroscience 2000; 97:419-24. [PMID: 10828524 DOI: 10.1016/s0306-4522(00)00087-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Apolipoprotein E genotype is an important risk factor of Alzheimer's disease, which is associated with the degeneration of distinct brain neuronal systems. In the present study we employed apolipoprotein E-deficient mice and human apolipoprotein E3 and apolipoprotein E4 transgenic mice on a null mouse apolipoprotein E background, to examine the extent to which distinct brain neuronal systems are affected by apolipoprotein E and the isoform specificity of this effect. This was pursued by histological and autoradiographic measurements utilizing neuron specific presynaptic markers. The results thus obtained revealed significant reductions in the levels of brain cholinergic and noradrenergic nerve terminals in young apolipoprotein E-deficient mice and no changes in brain dopaminergic nerve terminals. These cholinergic and noradrenergic presynaptic derangements were ameliorated similarly in human apolipoprotein E3 and apolipoprotein E4 transgenic mice. In the case of the cholinergic system, this resulted in complete reversal of the presynaptic deficits, whereas in the case of the noradrenergic neurons the amelioration was partial. These findings suggest that brain cholinergic and noradrenergic neurons are markedly more dependent on brain apolipoprotein E than brain dopaminergic neurons and that the isoform specificity of these effects is not apparent at a young age under non-challenged conditions.
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Affiliation(s)
- S Chapman
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Ramat Aviv, Israel
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Puoliväli J, Miettinen R, Pradier L, Riekkinen P. Apolipoprotein E-deficient mice are not more susceptible to the biochemical and memory deficits induced by nucleus basalis lesion. Neuroscience 2000; 96:291-7. [PMID: 10683569 DOI: 10.1016/s0306-4522(99)00545-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We investigated whether the nucleus basalis lesion induced by quisqualic acid was associated with a more severe impairment of spatial navigation in a water maze, a greater reduction in frontal choline acetyltransferase activity and decrease in the number of choline acetyltransferase-positive neurons in the nucleus basalis in apolipoprotein E-deficient mice than in control mice. We also studied the effect of ageing on water maze spatial navigation and cortical choline acetyltransferase activity in 16-month-old control and apolipoprotein E-deficient mice. We found that the lesion decreased choline acetyltransferase-positive neurons in the nucleus basalis and frontal choline acetyltransferase activity equally in control and apolipoprotein E-deficient mice. The nucleus basalis lesion had no effect on the initial acquisition in the water maze in control and apolipoprotein E-deficient mice after 25 or 106 days of recovery. However, the nucleus basalis lesion impaired the reversal learning in the water maze similarly in both strains after 25 days of recovery, but had no effect after 106 days of recovery. Finally, water maze spatial navigation and cortical choline acetyltransferase activity were similar in old control and apolipoprotein E-deficient mice. These results suggest that young and old apolipoprotein E-deficient mice do not have impairments in cholinergic activity or spatial navigation. Furthermore, apolipoprotein E deficiency does not increase the sensitivity to cholinergic and spatial navigation deficits induced by lesioning of the nucleus basalis with an excitatory amino acid and does not slow down the behavioral recovery.
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Affiliation(s)
- J Puoliväli
- Department of Neuroscience and Neurology, University of Kuopio and Kuopio University Hospital, P.O. Box 1627, FIN-70211, Kuopio, Finland.
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41
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Hellström-Lindahl E. Modulation of beta-amyloid precursor protein processing and tau phosphorylation by acetylcholine receptors. Eur J Pharmacol 2000; 393:255-63. [PMID: 10771022 DOI: 10.1016/s0014-2999(00)00028-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurofibrillary lesions and senile plaques that are composed mainly of hyperphosphorylated tau protein and the amyloid-beta peptide derived from the amyloid precursor protein, respectively, are classical hallmarks of Alzheimer's disease. A number of studies strongly suggests that amyloid-beta formation and amyloid depositions are linked to the pathogenesis of Alzheimer's disease. Recent findings suggest that very low concentrations of the amyloid-beta can inhibit various cholinergic neurotransmitter functions independently of apparent neurotoxicity. Many factors have been shown to influence the processing of amyloid precursor protein, including activation of muscarinic and nicotinic receptors. This review focus on some recent studies concerning the regulation of amyloid precursor protein processing and modulation of tau phosphorylation by acetylcholine receptor stimulation and how cholinergic deficits and amyloid-beta might be related to one another.
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Affiliation(s)
- E Hellström-Lindahl
- Department of Clinical Neuroscience, Occupational Therapy and Elderly Care Research, Division of Molecular Neuropharmacology, Karolinska Institutet, Huddinge University Hospital, Sweden.
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Gozes I, Bassan M, Zamostiano R, Pinhasov A, Davidson A, Giladi E, Perl O, Glazner GW, Brenneman DE. A novel signaling molecule for neuropeptide action: activity-dependent neuroprotective protein. Ann N Y Acad Sci 2000; 897:125-35. [PMID: 10676441 DOI: 10.1111/j.1749-6632.1999.tb07884.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complete coding sequence of a novel protein (828 amino acids, pI 5.99), a potential new mediator of vasoactive intestinal peptide (VIP) activity was recently revealed. The expression of this molecule, activity-dependent neuroprotective protein (ADNP), was augmented in the presence of VIP, in cerebral cortical astrocytes. The mRNA transcripts encoding ADNP were enriched in the mouse hippocampus and cerebellum. The protein deduced sequence contained the following: (1) a unique peptide, NAPVSIPQ, sharing structural and immunological homologies with the previously reported, activity-dependent neurotrophic factor (ADNF) and exhibiting neuroprotection in vitro and in vivo; (2) a glutaredoxin active site; and (3) a classical zinc binding domain. Comparative studies suggested that the peptide, NAPVSIPQ (NAP), was more efficacious than peptides derived from ADNF. ADNP, a potential mediator of VIP-associated neuronal survival, and the new peptide, a potential lead compound for drug design, are discussed below.
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Affiliation(s)
- I Gozes
- Department of Clinical Biochemistry, Sackler School of Medicine, Tel Aviv University, Israel.
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Hypothalamic-pituitary-adrenal dysfunction in Apoe(-/-) mice: possible role in behavioral and metabolic alterations. J Neurosci 2000. [PMID: 10684907 DOI: 10.1523/jneurosci.20-05-02064.2000] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Several neurological diseases are frequently accompanied by dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates the secretion of glucocorticoids (GCs), which play important roles in diverse brain functions, including cognition, emotion, and feeding. Under physiological conditions, GCs are adaptive and beneficial; however, prolonged elevations in GC levels may contribute to neurodegeneration and brain dysfunction. In the current study, we demonstrate that apolipoprotein E (apoE) deficiency results in age-dependent dysregulation of the HPA axis through a mechanism affecting primarily the adrenal gland. Apoe(-/-) mice, which develop neurodegenerative alterations as they age, had an age-dependent increase in basal adrenal corticosterone content and abnormally increased plasma corticosterone levels after restraint stress, whereas their plasma and pituitary adrenocorticotropin levels were either unchanged or lower than those in controls. HPA axis dysregulation was associated with behavioral and metabolic alterations. When anxiety levels were assessed in the elevated plus maze, Apoe(-/-) mice showed more anxiety than wild-type controls. Apoe(-/-) mice also showed reduced activity in the open field. Finally, Apoe(-/-) mice showed age-dependent increases in food and water intake, stomach and body weights, and decreases in brown and white adipose tissues. These results support a key role for apoE in the tonic inhibition of steroidogenesis and HPA axis activity and have important implications for the behavioral analysis of Apoe(-/-) mice.
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Puoliväli J, Pradier L, Riekkinen P. Impaired recovery of noradrenaline levels in apolipoprotein E-deficient mice after N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine lesion. Neuroscience 2000; 95:353-8. [PMID: 10658614 DOI: 10.1016/s0306-4522(99)00448-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We investigated the effect of the noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) (1 or 3 x 50 mg/kg, intraperitoneally), on hippocampal, cortical and cerebellar noradrenaline levels after recovery of one, five and 11 months in control and apolipoprotein E-deficient mice. Apolipoprotein E-deficient mice had lower hippocampal noradrenaline levels than control mice. DSP-4-lesioned control mice had a more extensive recovery of hippocampal and cortical noradrenaline levels than DSP-4-lesioned apoE-deficient mice after five months' survival. Furthermore, the hippocampal noradrenaline levels after five and 11 months and cortical noradrenaline levels after five months of recovery had slightly recovered in control but not in apolipoprotein E-deficient mice treated with a single dose of DSP-4 compared with mice treated with three doses of DSP-4. These results show that apolipoprotein E-deficient mice have impaired recovery capacity in their locus coeruleus neurons.
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Affiliation(s)
- J Puoliväli
- Department of Neuroscience and Neurology, University of Kuopio and Kuopio University Hospital, Finland
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45
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46
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Arnon R, Silman I, Tarrab-Hazdai R. Acetylcholinesterase of Schistosoma mansoni--functional correlates. Contributed in honor of Professor Hans Neurath's 90th birthday. Protein Sci 1999; 8:2553-61. [PMID: 10631970 PMCID: PMC2144239 DOI: 10.1110/ps.8.12.2553] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Acetylcholinesterase (AChE) is an enzyme broadly distributed in many species, including parasites. It occurs in multiple molecular forms that differ in their quaternary structure and mode of anchoring to the cell surface. This review summarizes biochemical and immunological investigations carried out in our laboratories on AChE of the helmint, Schistosoma mansoni. AChE appears in S. mansoni in two principal molecular forms, both globular, with sedimentation coefficients of approximately 6.5 and 8 S. On the basis of their substrate specificity and sensitivity to inhibitors, both are "true" acetylcholinesterases. Approximately half of the AChE activity of S. mansoni is located on the outer surface of the parasite, attached to the tegumental membrane via a covalently attached glycosylphosphatidylinositol anchor. The remainder is located within the parasite, mainly associated with muscle tissue. Whereas the internal enzyme is most likely involved in termination of neurotransmission at cholinergic synapses, the role of the surface enzyme remains to be established; there are, however, indications that it is involved in signal transduction. The two forms of AChE differ in their heparin-binding properties, only the internal 8 S form of the AChE being retained on a heparin column. The two forms differ also in their immunological specificity, since they are selectively recognized by different monoclonal antibodies. Polyclonal antibodies raised against S. mansoni AChE purified by affinity chromatography are specific for the parasite AChE, reacting with both molecular forms, but do not recognize AChE from other species. They interact with the surface-localized enzyme on the intact organism, and produce almost total complement-dependent killing of the parasite. S. mansoni AChE is thus demonstrated to be a functional protein, involved in multifaceted activities, which can serve as a suitable candidate for diagnostic purposes, vaccine development, and drug design.
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Affiliation(s)
- R Arnon
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel.
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47
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Affiliation(s)
- I Veinbergs
- Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla 92093-0624, USA
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48
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Veinbergs I, Mante M, Jung MW, Van Uden E, Masliah E. Synaptotagmin and synaptic transmission alterations in apolipoprotein E-deficient mice. Prog Neuropsychopharmacol Biol Psychiatry 1999; 23:519-31. [PMID: 10378234 DOI: 10.1016/s0278-5846(99)00013-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
1. Aged apoE-deficient mice and age-matched controls were tested for cognitive alterations in the Morris water maze. 2. Water maze results were correlated with in vivo electrophysiology and expression of the synaptic protein synaptotagmin (p65). 3. Compared to age-matched controls, apolipoprotein E-deficient mice displayed significant performance impairment accompanied by in vivo electrophysiological alterations in the dentate gyrus. 4. Apolipoprotein E-deficient mice also showed a significant increase in the synaptic protein, synaptotagmin, a synaptic calcium sensor involved in neurotransmitter release. 5. Cognitive impairments in these animals may be associated with decreased synaptic excitability in hippocampal neurons and the regulatory role of apolipoprotein E in synaptic function might be mediated by modulation of the expression of calcium sensor proteins.
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49
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Connors WL, Ruzicka J. Flow injection microscopy for the study of intracellular calcium mobilization by muscarinic agonists. Anal Biochem 1999; 268:377-82. [PMID: 10075829 DOI: 10.1006/abio.1998.3073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study of cellular response to chemical agonists is essential in understanding the complex functions mediated by cell surface receptors. Flow injection microscopy has been used with the CHO-M1-WT3 cell line and the fluorescent Ca2+ indicator Fura-2-AM to monitor mobilization of internal Ca2+. Repeated stimulation of cells mounted in an inverted radial flow chamber allows the direct comparison of relative intracellular Ca2+ mobilization with respect to agonist dose. The process of determining dose-response relationships is simplified since an entire dose-response curve can be constructed from a distinct set of cells. Use of flow injection lends precision to the application and removal of agonists while allowing cellular activity to be monitored throughout the stimulation and recovery processes. In this work, dose-response curves have been constructed for the muscarinic agonists carbachol, acetylcholine, and pilocarpine resulting in EC50 values of 1.7 microM, 56 nM, and 6.8 microM, respectively.
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Affiliation(s)
- W L Connors
- Department of Chemistry, University of Washington, Seattle, Washington, 98195, USA
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50
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Abstract
A transgenic mouse model for Alzheimer's disease (AD) should mimic the age-dependent accumulation of beta-amyloid plaques, neurofibrillary tangles, neuronal cell death as well as display memory loss and behavioral deficits. Age-dependent accumulation of A beta deposits in mouse brain has been achieved in mice overexpressing mutant alleles of the amyloid precursor protein (APP). In contrast, mice bearing mutant alleles of the presenilin genes show increased production of the A beta42 peptide, but do not form amyloid deposits unless mutant alleles of APP are also overproduced. Furthermore, the onset of A beta deposition is greatly accelerated, paralleling the involvement of presenilins in early onset AD. Studies of APP and presenilin transgenic mice have shown 1) the absence of a requirement for a maturation step in dense core plaque formation, 2) evidence that beta-amyloid deposition is directed by regional factors, and 3) behavioral deficits are observed before A beta deposition. Crosses of APP transgenic mice with mice modified for known AD risk factors and "humanizing" the mouse may be necessary for complete replication of AD.
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Affiliation(s)
- S Y Guénette
- Department of Neurology, Massachusetts General Hospital, Charlestown 02129, USA.
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