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Naproxen as a potential candidate for promoting rivastigmine anti-Alzheimer activity against aluminum chloride-prompted Alzheimer's-like disease in rats; neurogenesis and apoptosis modulation as a possible underlying mechanism. Eur J Pharmacol 2022; 915:174695. [PMID: 34914971 DOI: 10.1016/j.ejphar.2021.174695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND AIM Alzheimer's disease (AD) is one of the leading causes of dependence and disability among the elderly worldwide. The traditional anti-Alzheimer medication, rivastigmine, one of the cholinesterase inhibitors (ChEIs), fails to achieve a definitive cure. We tested the hypothesis that naproxen administration to the rivastigmine-treated aluminum chloride (AlCl3) Alzheimer's rat model could provide an additive neuroprotective effect compared to rivastigmine alone. MATERIALS AND METHODS The studied groups were control (Cont), AlCl3 treated (Al), rivastigmine treated (RIVA), naproxen treated (Napro), and combined rivastigmine and naproxen treated (RIVA + Napro). Rats' memory, spatial learning, and cognitive behavior were assessed followed by evaluation of hippocampal acetylcholinesterase (AChE) activity. Hippocampal and cerebellar histopathology were thoroughly examined. Activated caspase-3 and the neuroepithelial stem cells marker; nestin expressions were immunohistochemically assayed. RESULTS AD rats displayed significantly impaired memory and cognitive function, augmented hippocampal AChE activity; massive neurodegeneration associated with enhanced astrogliosis, apoptosis, and impaired neurogenesis. Except for the enhancement of neurogenesis and suppression of apoptosis, the combination therapy had no additional neuroprotective benefit over rivastigmine-only therapy. CONCLUSION Naproxen's efficacy was established by its ability to function at the cellular level, improved neurogenesis, and decreased, apoptosis without having an additional mitigating impact on cognitive impairment in rivastigmine-treated AD rats.
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Llorente-Ovejero A, Martínez-Gardeazabal J, Moreno-Rodríguez M, Lombardero L, González de San Román E, Manuel I, Giralt MT, Rodríguez-Puertas R. Specific Phospholipid Modulation by Muscarinic Signaling in a Rat Lesion Model of Alzheimer's Disease. ACS Chem Neurosci 2021; 12:2167-2181. [PMID: 34037379 PMCID: PMC9162383 DOI: 10.1021/acschemneuro.1c00169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
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Alzheimer’s disease (AD) represents
the most common cause
of dementia worldwide and has been consistently associated with the
loss of basal forebrain cholinergic neurons (BFCNs) leading to impaired
cholinergic neurotransmission, aberrant synaptic function, and altered
structural lipid metabolism. In this sense, membrane phospholipids
(PLs) can be used for de novo synthesis of choline (Ch) for the further
obtaining of acetylcholine (ACh) when its availability is compromised.
Specific lipid species involved in the metabolism of Ch have been
identified as possible biomarkers of phenoconversion to AD. Using
a rat model of BFCN lesion, we have evaluated the lipid composition
and muscarinic signaling in brain areas related to cognitive processes.
The loss of BFCN resulted in alterations of varied lipid species related
to Ch metabolism at nucleus basalis magnocellularis (NMB) and cortical
projection areas. The activity of muscarinic receptors (mAChR) was
decreased in the NMB and increased in the hippocampus according to
the subcellular distribution of M1/M2 mAChR
which could explain the learning and memory impairment reported in
this AD rat model. These results suggest that the modulation of specific
lipid metabolic routes could represent an alternative therapeutic
strategy to potentiate cholinergic neurotransmission and preserve
cell membrane integrity in AD.
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Affiliation(s)
- Alberto Llorente-Ovejero
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Jonatan Martínez-Gardeazabal
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Marta Moreno-Rodríguez
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Laura Lombardero
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Estíbaliz González de San Román
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
- Neurodegenerative Diseases, BioCruces Bizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - María Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
- Neurodegenerative Diseases, BioCruces Bizkaia Health Research Institute, 48903 Barakaldo, Spain
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Llorente-Ovejero A, Manuel I, Lombardero L, Giralt MT, Ledent C, Giménez-Llort L, Rodríguez-Puertas R. Endocannabinoid and Muscarinic Signaling Crosstalk in the 3xTg-AD Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2019; 64:117-136. [PMID: 29865071 DOI: 10.3233/jad-180137] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endocannabinoid system, which modulates emotional learning and memory through CB1 receptors, has been found to be deregulated in Alzheimer's disease (AD). AD is characterized by a progressive decline in memory associated with selective impairment of cholinergic neurotransmission. The functional interplay of endocannabinoid and muscarinic signaling was analyzed in seven-month-old 3xTg-AD mice following the evaluation of learning and memory of an aversive stimulus. Neurochemical correlates were simultaneously studied with both receptor and functional autoradiography for CB1 and muscarinic receptors, and regulations at the cellular level were depicted by immunofluorescence. 3xTg-AD mice exhibited increased acquisition latencies and impaired memory retention compared to age-matched non-transgenic mice. Neurochemical analyses showed changes in CB1 receptor density and functional coupling of CB1 and muscarinic receptors to Gi/o proteins in several brain areas, highlighting that observed in the basolateral amygdala. The subchronic (seven days) stimulation of the endocannabinoid system following repeated WIN55,212-2 (1 mg/kg) or JZL184 (8 mg/kg) administration induced a CB1 receptor downregulation and CB1-mediated signaling desensitization, normalizing acquisition latencies to control levels. However, the observed modulation of cholinergic neurotransmission in limbic areas did not modify learning and memory outcomes. A CB1 receptor-mediated decrease of GABAergic tone in the basolateral amygdala may be controlling the limbic component of learning and memory in 3xTg-AD mice. CB1 receptor desensitization may be a plausible strategy to improve behavior alterations associated with genetic risk factors for developing AD.
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Affiliation(s)
- Alberto Llorente-Ovejero
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, Leioa, Spain
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, Leioa, Spain
| | - Laura Lombardero
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, Leioa, Spain
| | - Maria Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, Leioa, Spain
| | - Catherine Ledent
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, Brussels, Belgium
| | - Lydia Giménez-Llort
- Department of Psychiatry and Forensic Medicine, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, Leioa, Spain
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. K, . Y, Bais S. Neuroprotective Effect of Protocatechuic Acid Through MAO-B Inhibition in Aluminium Chloride Induced Dementia of Alzheimer’s Type in Rats. INT J PHARMACOL 2018. [DOI: 10.3923/ijp.2018.879.888] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Blockage of High-Affinity Choline Transporter Increases Visceral Hypersensitivity in Rats with Chronic Stress. Gastroenterol Res Pract 2018; 2018:9252984. [PMID: 29849603 PMCID: PMC5904806 DOI: 10.1155/2018/9252984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/14/2018] [Indexed: 12/19/2022] Open
Abstract
Background Visceral hypersensitivity is a common feature of irritable bowel syndrome. Cholinergic system involves in the development of visceral hypersensitivity, and high-affinity choline transporter (CHT1) is of crucial importance in choline uptake system. However, involvement of CHT1 in visceral hypersensitivity remains unknown. The research aimed to study the CHT1 expression in dorsal root ganglions (DRGs) and the role of CHT1 in visceral hypersensitivity. Methods Repetitive water avoidance stress (WAS) was used to induce visceral hypersensitivity in rats. Colorectal distension (CRD) was determined, and the abdominal withdrawal reflex (AWR) and threshold intensity data were recorded to measure the visceral sensitivity. After intraperitoneal injection of hemicholinium-3 (HC-3), the specific inhibitor of CHT1, CRD data were also recorded. The CHT1 expression of DRGs was investigated by Western blotting, immunohistochemistry, and quantitative RT-PCR. Acetylcholine levels in the DRGs were detected by the assay kit. Results Repetitive WAS increased the AWR score of CRD at high distension pressure and decreased the mean threshold of rats. The CHT1 expression and acetylcholine concentration of DRG were significantly increased in WAS rats. After the administration of HC-3, the AWR score in WAS group was significantly increased at higher distension pressure while the threshold intensity was significantly reduced compared to the normal saline group. Acetylcholine concentration was significantly lower than the normal saline rats. Conclusion Our research firstly reports that CHT1 is overexpressed in noninflammatory visceral hypersensitivity, and blockage of CHT1 can enhance the visceral hypersensitivity. CHT1 may play an inhibitory role in visceral hypersensitivity.
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Fernandes J, Mudgal J, Rao CM, Arora D, Basu Mallik S, Pai KSR, Nampoothiri M. N-acetyl-L-tryptophan, a substance-P receptor antagonist attenuates aluminum-induced spatial memory deficit in rats. Toxicol Mech Methods 2018; 28:328-334. [PMID: 29185389 DOI: 10.1080/15376516.2017.1411412] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Neuroinflammation plays an important role in the pathophysiology of Alzheimer's disease. Neurokinin substance P is a key mediator which modulates neuroinflammation through neurokinin receptor. Involvement of substance P in Alzheimer's disease is still plausible and various controversies exist in this hypothesis. Preventing the deleterious effects of substance P using N-acetyl-L-tryptophan, a substance P antagonist could be a promising therapeutic strategy. This study was aimed to evaluate the effect of N-acetyl-L-tryptophan on aluminum induced spatial memory alterations in rats. Memory impairment was induced using aluminum chloride (AlCl3) at a dose of 10 mg/kg for 42 d. After induction of dementia, rats were exposed to 30 and 50 mg/kg of N-acetyl-L-tryptophan for 28 d. Spatial memory alterations were measured using Morris water maze. Acetylcholinesterase activity and antioxidant enzyme glutathione level were assessed in hippocampus, frontal cortex and striatum. The higher dose of N-acetyl-L-tryptophan (50 mg/kg) significantly improved the aluminum induced memory alterations. N-acetyl-L-tryptophan exposure resulted in significant increase in acetylcholinesterase activity and glutathione level in hippocampus. The neuroprotective effect of N-acetyl-L-tryptophan could be due to its ability to block substance P mediated neuroinflammation, reduction in oxidative stress and anti-apoptotic properties. To conclude, N-acetyl-L-tryptophan may be considered as a novel neuroprotective therapy in Alzheimer's disease.
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Affiliation(s)
- Joylee Fernandes
- a Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , India
| | - Jayesh Mudgal
- a Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , India
| | | | - Devinder Arora
- a Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , India.,b School of Pharmacy , MHIQ, QUM Network, Griffith University , Goldcoast , Australia
| | - Sanchari Basu Mallik
- a Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , India
| | - K S R Pai
- a Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , India
| | - Madhavan Nampoothiri
- a Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , India
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Petrasek T, Skurlova M, Maleninska K, Vojtechova I, Kristofikova Z, Matuskova H, Sirova J, Vales K, Ripova D, Stuchlik A. A Rat Model of Alzheimer's Disease Based on Abeta42 and Pro-oxidative Substances Exhibits Cognitive Deficit and Alterations in Glutamatergic and Cholinergic Neurotransmitter Systems. Front Aging Neurosci 2016; 8:83. [PMID: 27148049 PMCID: PMC4837344 DOI: 10.3389/fnagi.2016.00083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/04/2016] [Indexed: 12/24/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most serious human, medical, and socioeconomic burdens. Here we tested the hypothesis that a rat model of AD (Samaritan; Taconic Pharmaceuticals, USA) based on the application of amyloid beta42 (Abeta42) and the pro-oxidative substances ferrous sulfate heptahydrate and L-buthionine-(S, R)-sulfoximine, will exhibit cognitive deficits and disruption of the glutamatergic and cholinergic systems in the brain. Behavioral methods included the Morris water maze (MWM; long-term memory version) and the active allothetic place avoidance (AAPA) task (acquisition and reversal), testing spatial memory and different aspects of hippocampal function. Neurochemical methods included testing of the NR1/NR2A/NR2B subunits of NMDA receptors in the frontal cortex and CHT1 transporters in the hippocampus, in both cases in the right and left hemisphere separately. Our results show that Samaritan rats(™) exhibit marked impairment in both the MWM and active place avoidance tasks, suggesting a deficit of spatial learning and memory. Moreover, Samaritan rats exhibited significant changes in NR2A expression and CHT1 activity compared to controls rats, mimicking the situation in patients with early stage AD. Taken together, our results corroborate the hypothesis that Samaritan rats are a promising model of AD in its early stages.
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Affiliation(s)
- Tomas Petrasek
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of SciencesPrague, Czech Republic; National Institute of Mental HealthKlecany, Czech Republic
| | - Martina Skurlova
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Kristyna Maleninska
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Iveta Vojtechova
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | | | - Hana Matuskova
- National Institute of Mental Health Klecany, Czech Republic
| | - Jana Sirova
- National Institute of Mental Health Klecany, Czech Republic
| | - Karel Vales
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Daniela Ripova
- National Institute of Mental Health Klecany, Czech Republic
| | - Ales Stuchlik
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
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Insulin Regulates the Activity of the High-Affinity Choline Transporter CHT. PLoS One 2015; 10:e0132934. [PMID: 26161852 PMCID: PMC4498808 DOI: 10.1371/journal.pone.0132934] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 06/21/2015] [Indexed: 12/22/2022] Open
Abstract
Studies in humans and animal models show that neuronal insulin resistance increases the risk of developing Alzheimer’s Disease (AD), and that insulin treatment may promote memory function. Cholinergic neurons play a critical role in cognitive and attentional processing and their dysfunction early in AD pathology may promote the progression of AD pathology. Synthesis and release of the neurotransmitter acetylcholine (ACh) is closely linked to the activity of the high-affinity choline transporter protein (CHT), but the impact of insulin receptor signaling and neuronal insulin resistance on these aspects of cholinergic function are unknown. In this study, we used differentiated SH-SY5Y cells stably-expressing CHT proteins to study the effect of insulin signaling on CHT activity and function. We find that choline uptake activity measured after acute addition of 20 nM insulin is significantly lower in cells that were grown for 24 h in media containing insulin compared to cells grown in the absence of insulin. This coincides with loss of ability to increase phospho-Protein Kinase B (PKB)/Akt levels in response to acute insulin stimulation in the chronic insulin-treated cells. Inhibition of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3-kinase) in cells significantly lowers phospho-PKB/Akt levels and decreases choline uptake activity. We show total internal reflection microscopy (TIRF) imaging of the dynamic movement of CHT proteins in live cells in response to depolarization and drug treatments. These data show that acute exposure of depolarized cells to insulin is coupled to transiently increased levels of CHT proteins at the cell surface, and that this is attenuated by chronic insulin exposure. Moreover, prolonged inhibition of PI3-kinase results in enhanced levels of CHT proteins at the cell surface by decreasing their rate of internalization.
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Modulatory role of simvastatin against aluminium chloride-induced behavioural and biochemical changes in rats. Behav Neurol 2015; 2015:210169. [PMID: 25802481 PMCID: PMC4329790 DOI: 10.1155/2015/210169] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/29/2014] [Accepted: 01/07/2015] [Indexed: 12/29/2022] Open
Abstract
Objectives. Aluminium, a neurotoxic agent in humans, has been implicated in the pathogenesis of neurodegenerative disorders. In this study, we examined the behavioral and biochemical effects of aluminium in rats with special emphasis on memory centres, namely, hippocampus and frontal cortex. Further, the effect of simvastatin treatment on aluminium intoxication was evaluated. Methods. Rats were exposed to aluminium chloride (AlCl3) for 60 days. Simvastatin (10 mg/kg/p.o.) and rivastigmine (1 mg/kg/p.o.) were administered daily prior to AlCl3. Behavioral parameters were assessed using Morris water maze test and actophotometer followed by biochemical investigations, namely, acetylcholinesterase (AChE) activity, TNF-α level, antioxidant enzymes (GSH, catalase), lipid peroxidation, and nitrite level in hippocampus and frontal cortex. Triglycerides, total cholesterol, LDL, and HDL levels in serum were also determined. Key Findings. Simvastatin treatment improved cognitive function and locomotor activity in rats. Simvastatin reversed hyperlipidemia and significantly rectified the deleterious effect of AlCl3 on AChE activity. Further, in hippocampus and frontal cortex, aluminium-induced elevation in nitrite and TNF-α and reduction in antioxidant enzymes were inhibited by simvastatin. Conclusion. To conclude, the present study suggests that simvastatin per se protects the neurons in hippocampus and frontal cortex from AlCl3, an environmental toxin.
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Yegla B, Parikh V. Rejuvenating procholinergic treatments for cognition enhancement in AD: current challenges and future prospects. Front Syst Neurosci 2015; 8:254. [PMID: 25674054 PMCID: PMC4309160 DOI: 10.3389/fnsys.2014.00254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 12/29/2014] [Indexed: 11/23/2022] Open
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3-D-QSAR and docking studies on the neuronal choline transporter. Bioorg Med Chem Lett 2010; 20:4870-7. [DOI: 10.1016/j.bmcl.2010.06.090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 06/14/2010] [Accepted: 06/15/2010] [Indexed: 11/21/2022]
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MKC-231, a choline uptake enhancer: (3) mode of action of MKC-231 in the enhancement of high-affinity choline uptake. J Neural Transm (Vienna) 2008; 115:1037-46. [DOI: 10.1007/s00702-008-0049-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 03/28/2008] [Indexed: 10/22/2022]
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MKC-231, a choline uptake enhancer: (2) Effect on synthesis and release of acetylcholine in AF64A-treated rats. J Neural Transm (Vienna) 2008; 115:1027-35. [DOI: 10.1007/s00702-008-0048-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 03/28/2008] [Indexed: 10/22/2022]
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Xie J, Guo Q. Par-4 Inhibits Choline Uptake by Interacting with CHT1 and Reducing Its Incorporation on the Plasma Membrane. J Biol Chem 2004; 279:28266-75. [PMID: 15090548 DOI: 10.1074/jbc.m401495200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CHT1 is a Na(+)- and Cl(-)-dependent, hemicholinium-3 (HC-3)-sensitive, high affinity choline transporter. Par-4 (prostate apoptosis response-4) is a leucine zipper protein involved in neuronal degeneration and cholinergic signaling in Alzheimer's disease. We now report that Par-4 is a negative regulator of CHT1 choline uptake activity. Transfection of neural IMR-32 cells with human CHT1 conferred Na(+)-dependent, HC-3-sensitive choline uptake that was effectively inhibited by cotransfection of Par-4. Mapping studies indicated that the C-terminal half of Par-4 was physically involved in interacting with CHT1, and the absence of Par-4.CHT1 complex formation precluded the loss of CHT1-mediated choline uptake induced by Par-4, indicating that Par-4.CHT1 complex formation is essential. Kinetic and cell-surface biotinylation assays showed that Par-4 inhibited CHT1-mediated choline uptake by reducing CHT1 expression in the plasma membrane without significantly altering the affinity of CHT1 for choline or HC-3. These results suggest that Par-4 is directly involved in regulating choline uptake by interacting with CHT1 and by reducing its incorporation on the cell surface.
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Affiliation(s)
- Jun Xie
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
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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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16
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Skaddan MB, Jewett DM, Sherman PS, Kilbourn MR. (R)-N-[11C]methyl-3-pyrrolidyl benzilate, a high-affinity reversible radioligand for PET studies of the muscarinic acetylcholine receptor. Synapse 2002; 45:31-7. [PMID: 12112411 DOI: 10.1002/syn.10079] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We recently reported the synthesis and binding affinity of ligands for the muscarinic acetylcholine receptor (mAChR) based on both the pyrrolidyl and piperidyl benzilate scaffold. One of these, (R)-3-pyrrolidyl benzilate, was successfully radiolabeled with [(11)C]methyl triflate and the resulting compound, (R)-N-[(11)C]methyl-3-pyrrolidyl benzilate (3-[(11)C]NMPYB), was evaluated as a reversible, acetylcholine-sensitive tracer for the mAChR (K(i) of unlabeled 3-NMPYB is 0.72 nM). This compound displayed high, receptor-mediated retention in regions of the mouse and rat brain known to have high concentrations of mAChRs. Moreover, bolus studies in a pigtail monkey showed that this compound had superior clearance from the brain when compared to muscarinic radiotracers previously employed in human PET studies. Infusion studies in the same monkey revealed that it was possible to achieve equilibrium of radiotracer distribution for 3-[(11)C]NMPYB in both the striatum and cortex. Sensitivity to endogenous acetylcholine levels was evaluated by injecting phenserine (5 mg/kg) into rats prior to administration of 3-[(11)C]NMPYB in an equilibrium infusion protocol. This pretreatment produced a modest, statistically significant decrease (9-11%) in the distribution volume ratios for muscarinic receptor rich regions of the rat brain as compared to controls.
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Affiliation(s)
- Marc B Skaddan
- Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0552, USA
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Sihver W, Gillberg PG, Svensson AL, Nordberg A. Autoradiographic comparison of [3H](-)nicotine, [3H]cytisine and [3H]epibatidine binding in relation to vesicular acetylcholine transport sites in the temporal cortex in Alzheimer's disease. Neuroscience 1999; 94:685-96. [PMID: 10579560 DOI: 10.1016/s0306-4522(99)00295-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The laminar binding distribution of three nicotinic receptor agonists, [3H](-)nicotine, [3H]cytisine, and [3H]epibatidine, and their relation to the [3H]vesamicol binding, which is known to represent the vesicular acetylcholine transport sites, was performed employing in vitro autoradiography on the medial temporal cortex (Brodmann area 21). Autopsied brain tissue from nine Alzheimer patients and seven age-matched controls were used. The binding pattern of the three nicotinic ligands in the normal cortex was in general similar, showing binding maxima in the cortical layers I, III and V. The binding of [3H](-)nicotine, [3H]cytisine, and [3H]epibatidine was lower in the older controls and more uniform throughout the layers as compared with younger controls. There was a significant age-related decrease in the binding of the three nicotinic ligands within the controls (age range: 58 to 89 years; P[3H](-)nicotine = 0.002, P[3H]epibatidine = 0.010, P[3H]cytisine = 0.037). In the older controls, the [3H]epibatidine binding was much decreased as compared with that of [3H](-)nicotine and [3H]cytisine. This may indicate a higher selectivity of [3H]epibatidine for a nicotinic receptor subtype that is particularly affected by aging. The laminar binding pattern of [3H]vesamicol showed one maximum in the outer cortical layers II/III. The [3H]vesamicol binding did not change with aging. The binding of all ligands was significantly decreased in all layers of the temporal cortex in Alzheimer's disease, but the [3H]vesamicol binding decreased only half as much as the nicotinic receptors. Also, choline acetyltransferase activity was percentually more reduced than [3H]vesamicol binding in Alzheimer's disease. The cortical laminar binding pattern of all 3H-ligands was largely absent in the Alzheimer's disease cases. The less severe loss of vesicular acetylcholine transport sites as compared with the loss of the nicotinic receptors and choline acetyltransferase activity may suggest that vesamicol binding sites might be more preserved in presynaptic terminals still existing and thereby expressing compensatory capacity to maintain cholinergic activity.
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Affiliation(s)
- W Sihver
- PET Center Uppsala, Uppsala University, Sweden.
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Rodríguez-Puertas R, Pascual J, Vilaró T, Pazos A. Autoradiographic distribution of M1, M2, M3, and M4 muscarinic receptor subtypes in Alzheimer's disease. Synapse 1997; 26:341-50. [PMID: 9215593 DOI: 10.1002/(sici)1098-2396(199708)26:4<341::aid-syn2>3.0.co;2-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We studied the autoradiographic densities of all pharmacologically characterised muscarinic receptors (MR) in frontal, temporal, and visual cortex, hippocampal formation, and striatum in autopsied brains from 19 histopathologically verified patients of Alzheimer's disease (AD) and in matched controls. Almost all (16 of 19) of the AD cases were severe. In AD brains, total MR, M1, and M3 MR subtypes were found to be significantly decreased in entorhinal cortex and in most hippocampal strata. Total MR and M1 receptors were also significantly reduced in visual area and in frontal cortex of AD brains, respectively. M2 receptors were significantly reduced over hippocampal formation but increased significantly in striatum of AD brains as compared with controls. M3 receptors in AD were in the range of controls in neocortex and striatum, whereas the M4 receptor subtype was also preserved in all brain regions in AD brains when compared with controls. This is the first autoradiographic study analysing the distribution of all MR subtypes in AD brains. These changes in MR densities concur with the general pattern of neuronal degeneration occurring in AD brains and partly explain the poor response of AD cognitive decline to present cholinergic supplementation therapies. Although M3 and M4 MR were labelled with nonselective approaches, the preservation of M4 and to a lesser degree M3 MR subtypes in AD brains could open an alternative way for the symptomatic therapy of AD dementia.
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Mach RH, Voytko ML, Ehrenkaufer RL, Nader MA, Tobin JR, Efange SM, Parsons SM, Gage HD, Smith CR, Morton TE. Imaging of cholinergic terminals using the radiotracer [18F](+)-4-fluorobenzyltrozamicol: in vitro binding studies and positron emission tomography studies in nonhuman primates. Synapse 1997; 25:368-80. [PMID: 9097396 DOI: 10.1002/(sici)1098-2396(199704)25:4<368::aid-syn8>3.0.co;2-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The goal of the present set of studies was to characterize the in vitro binding properties and in vivo tissue kinetics for the vesicular acetylcholine transporter (VAcChT) radiotracer, [18F](+)-4-fluorobenzyltrozamicol ([18F](+)-FBT). In vitro binding studies were conducted in order to determine the affinity of the (+)- and (-)-stereoisomers of FBT for the VAcChT as well as sigma (sigma 1 and sigma 2) receptors. (+)-FBT was found to have a high affinity (Ki = 0.22 nM) for the VAcChT and lower affinities for sigma 1 (21.6 nM) and sigma 2 (35.9 nM) receptors, whereas (-)-FBT had similar affinities for the VAcChT and sigma 1 receptors (approximately 20 nM) and a lower affinity for sigma 2 (110 nM) receptors. PET imaging studies were conducted in rhesus monkeys (n = 3) with [18F](+)-FBT. [18F](+)-FBT was found to have a high accumulation and slow rate of washout from the basal ganglia, which is consistent with the labeling of cholinergic interneurons in this brain region. [18F](+)-FBT also displayed reversible binding kinetics during the 3 h time course of PET and produced radiolabeled metabolites that did not cross the blood-brain barrier. The results from the current in vitro and in vivo studies indicate that [18F](+)-FBT is a promising ligand for studying cholinergic terminal density, with PET, via the VAcChT.
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Affiliation(s)
- R H Mach
- Department of Radiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157, USA
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