scholarly journals Canadian Association of Neurosciences Review: The Role of Dopamine Receptor Function in Neurodegenerative Diseases

Author(s):  
Manon Lebel ◽  
Pierre Robinson ◽  
Michel Cyr

Dopamine (DA) receptors, which are heavily expressed in the caudate/putamen of the brain, represent the molecular target of several drugs used in the treatment of various neurological disorders, such as Parkinson's disease. Although most of the drugs are very effective in alleviating the symptoms associated with these conditions, their long-term utilization could lead to the development of severe side-effects. In addition to uncovering novel mediators of physiological DA receptor functions, recent research advances are suggesting a role of these receptors in toxic effects on neurons. For instance, accumulating evidence indicates that DA receptors, particularly D1 receptors, are central in the neuronal toxicity induced by elevated synaptic levels of DA. In this review, we will discuss recent findings on DA receptors as regulators of long term neuronal dysfunction and neurodegenerative processes.

Author(s):  
Peter R. Breggin

BACKGROUND: The vaccine/autism controversy has caused vast scientific and public confusion, and it has set back research and education into genuine vaccine-induced neurological disorders. The great strawman of autism has been so emphasized by the vaccine industry that it, and it alone, often appears in authoritative discussions of adverse effects of the MMR and other vaccines. By dismissing the chimerical vaccine/autism controversy, vaccine defenders often dismiss all genuinely neurological aftereffects of the MMR (measles, mumps, and rubella) and other vaccines, including well-documented events, such as relatively rare cases of encephalopathy and encephalitis. OBJECTIVE: This report explains that autism is not a physical or neurological disorder. It is not caused by injury or disease of the brain. It is a developmental disorder that has no physical origins and no physical symptoms. It is extremely unlikely that vaccines are causing autism; but it is extremely likely that they are causing more neurological damage than currently appreciated, some of it resulting in psychosocial disabilities that can be confused with autism and other psychosocial disorders. This confusion between a developmental, psychosocial disorder and a physical neurological disease has played into the hands of interest groups who want to deny that vaccines have any neurological and associated neuropsychiatric effects. METHODS: A review of the scientific literature, textbooks, and related media commentary is integrated with basic clinical knowledge. RESULTS: This report shows how scientific sources have used the vaccine/autism controversy to avoid dealing with genuine neurological risks associated with vaccines and summarizes evidence that vaccines, including the MMR, can cause serious neurological disorders. Manufacturers have been allowed by the US Food and Drug Administration (FDA) to gain vaccine approval without placebo-controlled clinical trials. CONCLUSIONS: The misleading vaccine autism controversy must be set aside in favor of examining actual neurological harms associated with vaccines, including building on existing research that has been ignored. Manufacturers of vaccines must be required to conduct placebo-controlled clinical studies for existing vaccines and for government approval of new vaccines. Many probable or confirmed neurological adverse events occur within a few days or weeks after immunization and could be detected if the trials were sufficiently large. Contrary to current opinion, large, long-term placebo-controlled trials of existing and new vaccines would be relatively easy and safe to conduct.


2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.


Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 767
Author(s):  
Courtney Davis ◽  
Sean I. Savitz ◽  
Nikunj Satani

Ischemic stroke is a debilitating disease and one of the leading causes of long-term disability. During the early phase after ischemic stroke, the blood-brain barrier (BBB) exhibits increased permeability and disruption, leading to an influx of immune cells and inflammatory molecules that exacerbate the damage to the brain tissue. Mesenchymal stem cells have been investigated as a promising therapy to improve the recovery after ischemic stroke. The therapeutic effects imparted by MSCs are mostly paracrine. Recently, the role of extracellular vesicles released by these MSCs have been studied as possible carriers of information to the brain. This review focuses on the potential of MSC derived EVs to repair the components of the neurovascular unit (NVU) controlling the BBB, in order to promote overall recovery from stroke. Here, we review the techniques for increasing the effectiveness of MSC-based therapeutics, such as improved homing capabilities, bioengineering protein expression, modified culture conditions, and customizing the contents of EVs. Combining multiple techniques targeting NVU repair may provide the basis for improved future stroke treatment paradigms.


CNS Spectrums ◽  
2004 ◽  
Vol 9 (7) ◽  
pp. 523-529 ◽  
Author(s):  
Palmiero Monteleone ◽  
Antonio DiLieto ◽  
Eloisa Castaldo ◽  
Mario Maj

AbstractLeptin is an adipocyte-derived hormone, which is involved predominantly in the long-term regulation of body weight and energy balance by acting as a hunger suppressant signal to the brain. Leptin is also involved in the modulation of reproduction, immune function, physical activity, and some endogenous endocrine axes. Since anorexia nervosa (AN) and bulimia nervosa (BN) are characterized by abnormal eating behaviors, dysregulation of endogenous endocrine axes, alterations of reproductive and immune functions, and increased physical activity, extensive research has been carried out in the last decade in order to ascertain a role of this hormone in the pathophysiology of these syndromes. In this article, we review the available data on leptin physiology in patients with eating disorders. These data support the idea that leptin is not directly involved in the etiology of AN or BN. However, malnutrition-induced alterations in its physiology may contribute to the genesis and/or the maintenance of some clinical manifestations of AN and BN and may have an impact on the prognosis of AN.


2021 ◽  
Vol 28 ◽  
Author(s):  
Lucas Alexandre Santos Marzano ◽  
Fabyolla Lúcia Macedo de Castro ◽  
Caroline Amaral Machado ◽  
João Luís Vieira Monteiro de Barros ◽  
Thiago Macedo e Cordeiro ◽  
...  

: Traumatic brain injury (TBI) is a serious cause of disability and death among young and adult individuals, displaying complex pathophysiology including cellular and molecular mechanisms that are not fully elucidated. Many experimental and clinical studies investigated the potential relationship between TBI and the process by which neurons are formed in the brain, known as neurogenesis. Currently, there are no available treatments for TBI’s long-term consequences being the search for novel therapeutic targets, a goal of highest scientific and clinical priority. Some studies evaluated the benefits of treatments aimed at improving neurogenesis in TBI. In this scenario, herein, we reviewed current pre-clinical studies that evaluated different approaches to improving neurogenesis after TBI while achieving better cognitive outcomes, which may consist in interesting approaches for future treatments.


2017 ◽  
Vol 23 (6) ◽  
pp. 587-604 ◽  
Author(s):  
Julien Gibon ◽  
Philip A. Barker

Neurotrophins have been intensively studied and have multiple roles in the brain. Neurotrophins are first synthetized as proneurotrophins and then cleaved intracellularly and extracellularly. Increasing evidences demonstrate that proneurotrophins and mature neurotrophins exerts opposing role in the central nervous system. In the present review, we explore the role of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4) and their respective proform in cellular processes related to learning and memory. We focused on their roles in synaptic activity and plasticity in the brain with an emphasis on long-term potentiation, long-term depression, and basal synaptic transmission in the hippocampus and the temporal lobe area. We also discuss new findings on the role of the Val66Met polymorphism on the BDNF propeptide on synaptic activity.


STEMedicine ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. e43 ◽  
Author(s):  
Federico Iseppon ◽  
Manuel Arcangeletti

Pain afflicts billions of people worldwide, who suffer especially from long-term chronic pain. This gruelling condition affects the nervous system at all levels: from the brain to the spinal cord, the Dorsal Root Ganglia (DRG) and the peripheral fibres innervating the skin. The nature of the different molecular and cellular components of the somatosensory modalities, as well as the complexity of the peripheral and central circuitry are yet poorly understood. Light-based techniques such as optogenetics, in concert with the recent advances in single-cell genetic profiling, can help to elucidate the role of diverse neuronal sub-populations in the encoding of different sensory and painful stimuli by switching these neurons on and off via optically active proteins, namely opsins.  Recently, photopharmacology has emerged from the efforts made to advance optogenetics. The introduction of azo-benzene-based light-sensitive molecular switches has been applied to a wide variety of molecular targets, from ion channels and receptors to transporters, enzymes and many more, some of which are paramount for pain research and therapy. In this Review, we summarise the recent advances in the fields of optogenetics and photopharmacology and we discuss the use of light-based techniques for the study of acute and chronic pain physiology, as well as their potential for future therapeutic use to improve pain treatment.


Author(s):  
Ravi Ranjan Kumar ◽  
Lovekesh Singh ◽  
Amandeep Thakur ◽  
Shamsher Singh ◽  
Bhupinder Kumar

Background: Vitamins are the micronutrients required for boosting the immune system and managing any future infection. Vitamins are involved in neurogenesis, a defense mechanism working in neurons, metabolic reactions, neuronal survival, and neuronal transmission. Their deficiency leads to abnormal functions in the brain like oxidative stress, mitochondrial dysfunction, accumulation of proteins (synuclein, Aβ plaques), neurodegeneration, and excitotoxicity. Methods: In this review, we have compiled various reports collected from PubMed, Scholar Google, Research gate, and Science direct. The findings were evaluated, compiled, and represented in this manuscript. Conclusion: The deficiency of vitamins in the body causes various neurological disorders like Alzheimer’s disease, Parkinson’s disease, Huntington's disease, and depression. We have discussed the role of vitamins in neurological disorders and the normal human body. Depression is linked to a deficiency of vitamin-C and vitamin B. In the case of Alzheimer’s disease, there is a lack of vitamin-B1, B12, and vitamin-A, which results in Aβ-plaques. Similarly, in Parkinson’s disease, vitamin-D deficiency leads to a decrease in the level of dopamine, and imbalance in vitamin D leads to accumulation of synuclein. In MS, Vitamin-C and Vitamin-D deficiency causes demyelination of neurons. In Huntington's disease, vitamin- C deficiency decreases the antioxidant level, enhances oxidative stress, and disrupts the glucose cycle. Vitamin B5 deficiency in Huntington's disease disrupts the synthesis of acetylcholine and hormones in the brain.


2006 ◽  
Vol 361 (1471) ◽  
pp. 1159-1185 ◽  
Author(s):  
B Beck

Neuropeptide Y (NPY) is one the most potent orexigenic peptides found in the brain. It stimulates food intake with a preferential effect on carbohydrate intake. It decreases latency to eat, increases motivation to eat and delays satiety by augmenting meal size. The effects on feeding are mediated through at least two receptors, the Y1 and Y5 receptors. The NPY system for feeding regulation is mostly located in the hypothalamus. It is formed of the arcuate nucleus (ARC), where the peptide is synthesized, and the paraventricular (PVN), dorsomedial (DMN) and ventromedial (VMN) nuclei and perifornical area where it is active. This activity is modulated by the hindbrain and limbic structures. It is dependent on energy availability, e.g. upregulation with food deprivation or restriction, and return to baseline with refeeding. It is also sensitive to diet composition with variable effects of carbohydrates and fats. Leptin signalling and glucose sensing which are directly linked to diet type are the most important factors involved in its regulation. Absence of leptin signalling in obesity models due to gene mutation either at the receptor level, as in the Zucker rat, the Koletsky rat or the db / db mouse, or at the peptide level, as in ob / ob mouse, is associated with increased mRNA abundance, peptide content and/or release in the ARC or PVN. Other genetic obesity models, such as the Otsuka–Long–Evans–Tokushima Fatty rat, the agouti mouse or the tubby mouse, are characterized by a diminution in NPY expression in the ARC nucleus and by a significant increase in the DMN. Further studies are necessary to determine the exact role of NPY in these latter models. Long-term exposure to high-fat or high-energy palatable diets leads to the development of adiposity and is associated with a decrease in hypothalamic NPY content or expression, consistent with the existence of a counter-regulatory mechanism to diminish energy intake and limit obesity development. On the other hand, an overactive NPY system (increased mRNA expression in the ARC associated with an upregulation of the receptors) is characteristic of rats or rodent strains sensitive to dietary-induced obesity. Finally, NPY appears to play an important role in body weight and feeding regulation, and while it does not constitute the only target for drug treatment of obesity, it may nevertheless provide a useful target in conjunction with others.


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