The Interplay of Neurotransmitters in Alzheimer's Disease

CNS Spectrums ◽  
2005 ◽  
Vol 10 (S18) ◽  
pp. 6-9 ◽  
Author(s):  
Paul T. Francis
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nmda Receptors ◽  
Neuronal Damage ◽  
Cholinergic Neurons ◽  
Synaptic Cleft ◽  
Acetylcholinesterase Activity ◽  
Nmda Receptor Antagonist ◽  
Potential Synergy ◽  
And Function

AbstractEvidence exists for both cholinergic and glutamatergic involvement in the etiology of Alzheimer's disease. Acetylcholine (ACh), a neurotransmitter essential for processing memory and learning, is decreased in both concentration and function in patients with Alzheimer's disease. This deficit and other presynaptic cholinergic deficits, including loss of cholinergic neurons and decreased acetylcholinesterase activity, underscore the cholinergic hypothesis of Alzheimer's disease. The glutamatergic hypothesis links cognitive decline in patients with Alzheimer's to neuronal damage resulting from overactivation of N-methyl-D-aspartate (NMDA) receptors by glutamate. The sustained low-level activation of NMDA receptors, which are pivotal in learning and memory, may result from deficiencies in glutamate reuptake by astroglial cells in the synaptic cleft. This article reviews the roles of ACh and glutamate in Alzheimer's disease, with particular attention given to the overlap between cholinergic and glutamatergic pathways. In addition, the potential synergy between cholinesterase inhibitors and the NMDA receptor antagonist memantine in correcting neurologic abnormalities associated with Alzheimer's disease is addressed.

Protective Effect of Kaempferol on the Transgenic Drosophila Model of Alzheimer’s Disease

2018 ◽  
Vol 17 (6) ◽  
pp. 421-429 ◽  
Author(s):  
Tanveer Beg ◽  
Smita Jyoti ◽  
Falaq Naz ◽  
Rahul ◽  
Fahad Ali ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Beta ◽  
Neuronal Damage ◽  
Natural Antioxidants ◽  
Acetylcholinesterase Activity ◽  
Model Of Alzheimer’S Disease ◽  
Climbing Ability ◽  
Transgenic Drosophila

Background: Alzheimer’s disease (AD) is characterized by the accumulation and deposition of β-amyloid peptides leading to a progressive neuronal damage and cell loss. Besides several hypotheses for explaining the neurodegenerative mechanisms, oxidative stress has been considered to be one of them. Till date, there is no cure for AD, but the pathogenesis of the disease could be delayed by the use of natural antioxidants. In this context, we decided to study the effect of kaempferol against the transgenic Drosophila expressing human amyloid beta-42. Method: The AD flies were allowed to feed on the diet having 10, 20, 30 and 40µM of kaempferol for 30 days. After 30 days of exposure, the amyloid beta flies were studied for their climbing ability and Aversive Phototaxis Suppression assay. Amyloid beta flies head homogenate was prepared for estimating the oxidative stress markers, Caspase and acetylcholinesterase activity. Results: The results of the present study reveal that the exposure of AD flies to kaempferol delayed the loss of climbing ability, memory, reduced the oxidative stress and acetylcholinesterase activity. Conclusion: Kaempferol could be used as a possible therapeutic agent against the progression of the Alzheimer’s disease.

Oxidative Damage of Proteins Precedes Loss of Cholinergic Phenotype in the Septal Neurons of Olfactory Bulbectomized Mice

2021 ◽  
Vol 19 ◽  
Author(s):  
O.A. Nedogreeva ◽  
N.A. Evtushenko ◽  
A.O. Manolova ◽  
D.I. Peregud ◽  
A.A. Yakovlev ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Oxidative Damage ◽  
Cognitive Decline ◽  
Water Maze ◽  
Neuronal Damage ◽  
Cholinergic Neurons ◽  
Olfactory Bulbectomy ◽  
Cholinergic Dysfunction

Background: The development of cholinergic deficit is considered an early sign of a number of pathological conditions, including Alzheimer’s disease. Cholinergic dysfunction underlies cognitive decline associated with both normal aging and Alzheimer’s disease. Objective: Here, we studied a possible mechanism of functional impairment of cholinergic neurons using an olfactory bulbectomy model. Methods: Male mice were subjected to olfactory bulbectomy or sham surgery. Three weeks after that they were trained in Morris water maze and then euthanized one month after surgery. The cholinergic indices as well as the indices of oxidative stress were studied using immunohistochemistry, western blot and ELISA. Gene expression was studied using RT-qPCR. Results: The experimental treatment was followed by impaired learning of a standard spatial task in a water maze. This was associated with a decrease in the number of cells containing choline acetyltransferase (ChAT), in relation to total number of neurons in the medial septum and lower ChAT enzymatic activity in the hippocampus. However, the levels of mRNAs of ChAT, vesicular ACh transporter and acetylcholine esterase remained unchanged in bulbectomized mice compared to sham-operated animals. These alterations were preceded by the accumulation of protein-bound carbonyls, indicating oxidative damage of proteins, whereas oxidative damage of nucleic acids was not detected. Conclusion: We assume that in olfactory bulbectomy model, oxidative damage of proteins may cause cholinergic dysfunction rather than irreversible neuronal damage. These data indicate that cholinergic neurons of the basal forebrain are very sensitive to oxidative stress, which may be responsible for the appearance of early cognitive decline in Alzheimer’s disease.

scholarly journals Recent advances and current perspectives in treatment of Alzheimer’s disease

2020 ◽  
Vol 21 (1&2) ◽  
pp. 183-186
Author(s):  
Ekta Khare ◽  
Zeeshan Fatima
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nmda Receptor Antagonist ◽  
Phase Iii ◽  
Metal Chelators ◽  
Memory And Learning ◽  
Ache Inhibitors ◽  
Cerebral Neurons ◽  
Zinc Chelator ◽  
And Function

Dementia is a disorder which is associated with disruption of cerebral neurons, resulting in its characteristic symptomatology. Acetylcholine neurotransmitter is found to be significant for processing memory and learning. However it is diminished in both concentration and function in patients with Alzheimer disease. Nootropics are the drugs which is used to improve memory and learning by acting as AChEI (Acetyl cholineesterase inhibitors). Cognitive enhancers include drugs interacting with receptors (e.g. NMDA receptor antagonist: memantine), Enzymes (e.g. AChE inhibitors: tacrine, donepezil, galantamine), Antioxidants (e.g. resveratrol, curcumin, and acetyl-L-carnitine), Metal chelators (e.g. calcium and zinc chelator: DP-b99), Vaccines, Monoclonal antibodies (e.g. A beta-Amyloid: solanezumab under Phase III clinical trial). Apart from the pharmacological approaches, supplementation of a healthy diet and healthy physical & mental lifestyle impact cognitive research in the future. There is no remedy for AD. Contemporary treatments just relive the behaviourial symptoms.Treatment centers around making a superior personal satisfaction for the individuals with Alzheimer infection. As of late, undifferentiated cell innovation (stem cell technology), and Nanotechnology has given new bits of knowledge into the treatment of Alzheimer's disease. In this review, we talk about current indicative medicines and future difficulties for new potential illness altering treatments.             

scholarly journals Focused ultrasound delivery of a selective TrkA agonist rescues cholinergic function in a mouse model of Alzheimer’s disease

2020 ◽  
Vol 6 (4) ◽  
pp. eaax6646 ◽  
Author(s):  
K. Xhima ◽  
K. Markham-Coultes ◽  
H. Nedev ◽  
S. Heinen ◽  
H. U. Saragovi ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Focused Ultrasound ◽  
Cholinergic Neurons ◽  
Model Of Alzheimer’S Disease ◽  
Models Of Injury ◽  
Cholinergic Cell ◽  
Tgcrnd8 Mice ◽  
And Function ◽  
Neurotrophin Signaling

The degeneration of cholinergic neurons is a prominent feature of Alzheimer’s disease (AD). In animal models of injury and aging, nerve growth factor (NGF) enhances cholinergic cell survival and function, contributing to improved memory. In the presence of AD pathology, however, NGF-related therapeutics have yet to fulfill their regenerative potential. We propose that stimulating the TrkA receptor, without p75NTR activation, is key for therapeutic efficacy. Supporting this hypothesis, the selective TrkA agonist D3 rescued neurotrophin signaling in TgCRND8 mice, whereas NGF, interacting with both TrkA and p75NTR, did not. D3, delivered intravenously and noninvasively to the basal forebrain using MRI-guided focused ultrasound (MRIgFUS)–mediated blood-brain barrier (BBB) permeability activated TrkA-related signaling cascades and enhanced cholinergic neurotransmission. Recent clinical trials support the safety and feasibility of MRIgFUS BBB modulation in AD patients. Neuroprotective agents targeting TrkA, combined with MRIgFUS BBB modulation, represent a promising strategy to counter neurodegeneration in AD.

Acetylcholinesterase Inhibitory Potential and Antioxidant Activities of Five Cultivars of Rosa Damascena Mill. From Isparta, Turkey

2020 ◽  
Vol 18 (4) ◽  
pp. 354-359
Author(s):  
Shirin Tarbiat ◽  
Azize Simay Türütoğlu ◽  
Merve Ekingen
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Free Radical ◽  
Neurodegenerative Disorder ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Acetylcholinesterase Activity ◽  
Rosa Damascena ◽  
Free Radical Damage

Alzheimer's disease is a neurodegenerative disorder characterized by memory loss and impairment of language. Alzheimer's disease is strongly associated with oxidative stress and impairment in the cholinergic pathway, which results in decreased levels of acetylcholine in certain areas of the brain. Hence, inhibition of acetylcholinesterase activity has been recognized as an acceptable treatment against Alzheimer's disease. Nature provides an array of bioactive compounds, which may protect against free radical damage and inhibit acetylcholinesterase activity. This study compares the in vitro antioxidant and anticholinesterase activities of hydroalcoholic extracts of five cultivars of Rosa Damascena Mill. petals (R. damascena 'Bulgarica', R. damascena 'Faik', R. damascena 'Iranica', R. damascena 'Complex-635' and R. damascena 'Complex-637') from Isparta, Turkey. The antioxidant activities of the hydroalcoholic extracts were tested for ferric ion reduction and DPPH radical scavenging activities. The anti-acetylcholinesterase activity was also evaluated. All rose cultivars showed a high potency for scavenging free radical and inhibiting acetylcholinesterase activity. There was a significant correlation between antioxidant and acetylcholinesterase inhibitory activity. Among cultivars, Complex-635 showed the highest inhibitory effect with an IC50 value of 3.92 µg/mL. Our results suggest that all these extracts may have the potential to treat Alzheimer's disease with Complex-635 showing more promise.

Neuroprotective Effects of Ellagic Acid in Alzheimer's Disease: Focus on Underlying Molecular Mechanisms of Therapeutic Potential

2020 ◽  
Vol 26 ◽  
Author(s):  
Nimra Javaid ◽  
Muhammad Ajmal Shah ◽  
Azhar Rasul ◽  
Zunera Chauhdary ◽  
Uzma Saleem ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Ellagic Acid ◽  
Molecular Mechanisms ◽  
Neurodegenerative Disorder ◽  
Therapeutic Potential ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Acetylcholinesterase Activity ◽  
Neuroprotective Effects

: Neurodegeneration is a multifactorial process involved the different cytotoxic pathways that lead towards neuronal cell death. Alzheimer’s disease (AD) is a persistent neurodegenerative disorder that normally has a steady onset yet later on it worsens. The documented evidence of AD neuropathology manifested the neuro-inflammation, increased reactive oxygen, nitrogen species and decreased antioxidant protective process; mitochondrial dysfunction as well as increased level of acetylcholinesterase activity. Moreover, enhanced action of proteins leads towards neural apoptosis which have a vital role in the degeneration of neurons. The inability of commercial therapeutic options to treat AD with targeting single mechanism leads the attraction towards organic drugs. Ellagic acid is a dimer of gallic acid, latest studies expressed that ellagic acid can initiate the numerous cell signaling transmission and decrease the progression of disorders, involved in the degeneration of neurons. The influential property of ellagic acid to protect the neurons in neurodegenerative disorders is due to its antioxidant effect, iron chelating and mitochondrial protective effect. The main goal of this review is to critically analyze the molecular mode of action of ellagic acid against neurodegeneration.

Spirocyclohexadienones as an Uncommon Scaffold for Acetylcholinesterase Inhibitory Activity

2019 ◽  
Vol 15 (4) ◽  
pp. 373-382 ◽  
Author(s):  
Ralph C. Gomes ◽  
Renata P. Sakata ◽  
Wanda P. Almeida ◽  
Fernando Coelho
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Population Aging ◽  
Acetylcholinesterase Inhibitors ◽  
Acetylcholinesterase Activity ◽  
Docking Study ◽  
Biological Properties ◽  
Ache Inhibitor ◽  
Molecular Docking Study

Background: The most important cause of dementia affecting elderly people is the Alzheimer’s disease (AD). Patients affected by this progressive and neurodegenerative disease have severe memory and cognitive function impairments. Some medicines used for treating this disease in the early stages are based on inhibition of acetylcholinesterase. Population aging should contribute to increase the cases of patients suffering from Alzheimer's disease, thus requiring the development of new therapeutic entities for the treatment of this disease. Methods: The objective of this work is to identify new substances that have spatial structural similarity with donepezil, an efficient commercial drug used for the treatment of Alzheimer's disease, and to evaluate the capacity of inhibition of these new substances against the enzyme acetylcholinesterase. Results: Based on a previous results of our group, we prepared a set of 11 spirocyclohexadienones with different substitutions patterns in three steps and overall yield of up to 59%. These compounds were evaluated in vitro against acetylcholinesterase. We found that eight of them are able to inhibit the acetylcholinesterase activity, with IC50 values ranging from 0.12 to 12.67 µM. Molecular docking study indicated that the spirocyclohexadienone, 9e (IC50 = 0.12 µM), a mixedtype AChE inhibitor, showed a good interaction at active site of the enzyme, including the cationic (CAS) and the peripheral site (PAS). Conclusion: We described the first study aimed at investigating the biological properties of spirocyclohexadienones as acetylcholinesterase inhibitors. Thus, we have identified an inhibitor, which provided valuable insights for further studies aimed at the discovery of more potent acetylcholinesterase inhibitors.

In silico screening of pyridoxine carbamates for Anti-Alzheimer’s activities

2020 ◽  
Vol 20 ◽  
Author(s):  
Dnyaneshwar Baswar ◽  
Abha Sharma ◽  
Awanish Mishra
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
In Silico ◽  
Neurodegenerative Disorder ◽  
Biological Activities ◽  
Cholinergic Neurons ◽  
In Silico Screening ◽  
In Silico Studies ◽  
Bbb Permeability ◽  
Ld50 Value

Background: Alzheimer’s disease (AD), an irreversible complex neurodegenerative disorder, is most common type of dementia, with progressive loss of cholinergic neurons. Based on the multi- factorial etiology of Alzheimer’s disease, novel ligands strategy appears as up-coming approach for the development of newer molecules against AD. This study is envisaged to investigate anti-Alzheimer’s potential of 10 synthesized compounds. The screening of compounds (1-10) was carried out using in silico techniques. Methods: For in silico screening of physicochemical properties of compounds molinspiration property engine v.2018.03, Swiss ADME online web-server and pkCSM ADME were used. For pharmacodynamic prediction PASS software while toxicity profile of compounds were analyzed through ProTox-II online software. Simultaneously, molecular docking analysis was performed on mouse AChE enzyme (PDB ID:2JGE, obtained from RSCB PDB) using Auto Dock Tools 1.5.6. Results: Based on in silico studies, compound 9 and 10 have been found to have better drug likeness, LD50 value, and better anti-Alzheimer’s, nootropic activities. However, these compounds had poor blood brain barrier (BBB) permeability. Compound 4 and 9 were predicted with better docking score for AChE enzyme. Conclusion: The outcome of in silico studies have suggested, out of various substitutions at different positions of pyridoxine-carbamate, compound 9 have shown promising drug likeness, with better safety and efficacy profile for anti-Alzheimer’s activity. However, BBB permeability appears as one the major limitation of all these compounds. Further studies are required to confirm its biological activities.

Current Strategies and Novel Drug Approaches for Alzheimer Disease

2020 ◽  
Vol 19 (9) ◽  
pp. 676-690 ◽  
Author(s):  
Roma Ghai ◽  
Kandasamy Nagarajan ◽  
Meenakshi Arora ◽  
Parul Grover ◽  
Nazakat Ali ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cholinergic Neurons ◽  
Amyloid Plaque ◽  
Neural Pathways ◽  
Current Trends ◽  
Personality Changes ◽  
Traditional Therapies ◽  
Novel Drug ◽  
The Brain

Alzheimer’s Disease (AD) is a chronic, devastating dysfunction of neurons in the brain leading to dementia. It mainly arises due to neuronal injury in the cerebral cortex and hippocampus area of the brain and is clinically manifested as a progressive mental failure, disordered cognitive functions, personality changes, reduced verbal fluency and impairment of speech. The pathology behind AD is the formation of intraneuronal fibrillary tangles, deposition of amyloid plaque and decline in choline acetyltransferase and loss of cholinergic neurons. Tragically, the disease cannot be cured, but its progression can be halted. Various cholinesterase inhibitors available in the market like Tacrine, Donepezil, Galantamine, Rivastigmine, etc. are being used to manage the symptoms of Alzheimer’s disease. The paper’s objective is to throw light not only on the cellular/genetic basis of the disease, but also on the current trends and various strategies of treatment including the use of phytopharmaceuticals and nutraceuticals. Enormous literature survey was conducted and published articles of PubMed, Scifinder, Google Scholar, Clinical Trials.org and Alzheimer Association reports were studied intensively to consolidate the information on the strategies available to combat Alzheimer’s disease. Currently, several strategies are being investigated for the treatment of Alzheimer’s disease. Immunotherapies targeting amyloid-beta plaques, tau protein and neural pathways are undergoing clinical trials. Moreover, antisense oligonucleotide methodologies are being approached as therapies for its management. Phytopharmaceuticals and nutraceuticals are also gaining attention in overcoming the symptoms related to AD. The present review article concludes that novel and traditional therapies simultaneously promise future hope for AD treatment.

scholarly journals Plasma Neurofilament Light and Future Declines in Cognition and Function in Alzheimer’s Disease in the FIT-AD Trial

2021 ◽  
pp. 1-11
Author(s):  
Danni Li ◽  
Lin Zhang ◽  
Nathaniel W. Nelson ◽  
Michelle M. Mielke ◽  
Fang Yu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Daily Living ◽  
Short Term ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Linear Mixed Effects ◽  
Future Studies ◽  
Rate Of Decline ◽  
And Function

Background: Utilities of blood-based biomarkers in Alzheimer’s disease (AD) clinical trials remain unknown. Objective: To evaluate the ability of plasma neurofilament light chain (NfL) to predict future declines in cognition and activities of daily living (ADL) outcomes in 26 older adults with mild-to-moderate AD dementia from the FIT-AD Trial. Methods: Plasma NfL was measured at baseline and 3 and 6 months. Cognition and ADL were assessed using the AD Assessment Scale-Cognition (ADAS-Cog) and AD Uniform Dataset Instruments and Disability Assessment for Dementia (DAD), respectively, at baseline, 3, 6, 9, and 12 months. Linear mixed effects models were used to examine the associations between baseline or change in plasma NfL and changes in outcomes. Results: Higher baseline plasma NfL was associated with greater rate of decline in ADAS-Cog from baseline to 6 months (standardized estimate of 0.00462, p = 0.02853) and in ADL from baseline to 12 months (standardized estimate of –0.00284, p = 0.03338). Greater increase in plasma NfL in short term from baseline to 3 months was associated with greater rate of decline in memory and ADL from 3 to 6 months (standardized estimate of –0.04638 [0.003], p = 0.01635; standardized estimate of –0.03818, p = 0.0435) and greater rate of decline in ADL from 3 to 12 month (standardized estimate of –0.01492, p = 0.01082). Conclusion: This study demonstrated that plasma NfL might have the potential to predict cognitive and function decline up to 12 months. However, future studies with bigger sample sizes need to confirm the findings.

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