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Annual Review of Neuroscience Jul 2020Itch is a unique sensation that helps organisms scratch away external threats; scratching itself induces an immune response that can contribute to more itchiness. Itch... (Review)
Review
Itch is a unique sensation that helps organisms scratch away external threats; scratching itself induces an immune response that can contribute to more itchiness. Itch is induced chemically in the peripheral nervous system via a wide array of receptors. Given the superficial localization of itch neuron terminals, cells that dwell close to the skin contribute significantly to itch. Certain mechanical stimuli mediated by recently discovered circuits also contribute to the itch sensation. Ultimately, in the spinal cord, and likely in the brain, circuits that mediate touch, pain, and itch engage in cross modulation. Much of itch perception is still a mystery, but we present in this review the known ligands and receptors associated with itch. We also describe experiments and findings from investigations into the spinal and supraspinal circuitry responsible for the sensation of itch.
Topics: Animals; Brain; Humans; Neurons; Pain; Peripheral Nervous System; Pruritus; Spinal Cord
PubMed: 32075517
DOI: 10.1146/annurev-neuro-083019-024537 -
Biochemical Society Transactions Dec 2022The nervous system is composed of a variety of neurons and glial cells with different morphology and functions. In the mammalian peripheral nervous system (PNS) or the... (Review)
Review
The nervous system is composed of a variety of neurons and glial cells with different morphology and functions. In the mammalian peripheral nervous system (PNS) or the lower vertebrate central nervous system (CNS), most neurons can regenerate extensively after axotomy, while the neurons in the mammalian CNS possess only limited regenerative ability. This heterogeneity is common within and across species. The studies about the transcriptomes after nerve injury in different animal models have revealed a series of molecular and cellular events that occurred in neurons after axotomy. However, responses of various types of neurons located in different positions of individuals were different remarkably. Thus, researchers aim to find the key factors that are conducive to regeneration, so as to provide the molecular basis for solving the regeneration difficulties after CNS injury. Here we review the heterogeneity of axonal regeneration among different cell subtypes in different animal models or the same organ, emphasizing the importance of comparative studies within and across species.
Topics: Animals; Axons; Nerve Regeneration; Axotomy; Peripheral Nervous System; Central Nervous System; Mammals
PubMed: 36382964
DOI: 10.1042/BST20220624 -
Continuum (Minneapolis, Minn.) Aug 2021This article describes infections that affect the peripheral nervous system, including their clinical features, differential diagnoses, and treatments. (Review)
Review
PURPOSE OF REVIEW
This article describes infections that affect the peripheral nervous system, including their clinical features, differential diagnoses, and treatments.
RECENT FINDINGS
Rates of pyomyositis have increased recently in the United States, possibly because of an increase in risk factors such as IV drug use, obesity, and diabetes. Other peripheral nervous system infections, such as diphtheria, have become more common in older patients secondary to a lack of revaccination or waning immunity. Although recommended treatment regimens for most infections remain unchanged over recent years, debate over the ideal dosing and route of administration continues for some infections such as tetanus and leprosy (Hansen disease).
SUMMARY
Infections of the peripheral nervous system are varied in terms of the type of infection, localization, and potential treatment. Nerve conduction studies and EMG can help determine localization, which is key to determining an initial differential diagnosis. It is important to recognize infections quickly to minimize diagnostic delays that could lead to patient morbidity and mortality.
Topics: Aged; Diphtheria; Humans; Peripheral Nervous System; Peripheral Nervous System Diseases; Tetanus; United States
PubMed: 34623098
DOI: 10.1212/CON.0000000000000981 -
Current Issues in Molecular Biology 2021In vertebrates, the nervous system (NS) is composed of a peripheral collection of neurons (the peripheral nervous system, PNS), a central set found in the brain and... (Review)
Review
In vertebrates, the nervous system (NS) is composed of a peripheral collection of neurons (the peripheral nervous system, PNS), a central set found in the brain and spinal cord (the central nervous system, CNS). The NS is protected by rather complicated multi-layer barriers that allow access to nutrients and facilitate contact with the peripheral tissues, but block entry of pathogens and toxins. Virus infections usually begin in peripheral tissues and if these barriers are weakened, they can spread into the PNS and more rarely into the CNS. Most viral infections of the NS are opportunistic or accidental pathogens that gain access via the bloodstream (e.g., HIV and various arboviruses). But a few have evolved to enter the NS efficiently by invading neurons directly and by exploiting neuronal cell biology (e.g., rhabdoviruses and alphaherpesviruses). Most NS infections are devastating and difficult to manage. Remarkably, the alphaherpesviruses establish life-long quiescent infections in the PNS, with rare but often serious CNS pathology. In this review, we will focus on how alphaherpesviruses gain access to and spread in the NS, with particular emphasis on bidirectional transport and spread within and between neurons and neural circuits, which is regulated by complex viral-host protein interactions. Finally, we will describe the wide use of alphaherpesviruses as tools to study nerve connectivity and function in animal models.
Topics: Alphaherpesvirinae; Animals; Central Nervous System; Herpesviridae Infections; Humans; Neurons; Peripheral Nervous System
PubMed: 32723924
DOI: 10.21775/cimb.041.001 -
International Journal of Molecular... Sep 2023Neurodegenerative diseases are characterized by the progressive degeneration or death of neurons in the central or peripheral nervous system [...].
Neurodegenerative diseases are characterized by the progressive degeneration or death of neurons in the central or peripheral nervous system [...].
Topics: Humans; Neurodegenerative Diseases; Neurons; Peripheral Nervous System
PubMed: 37762040
DOI: 10.3390/ijms241813721 -
Revue Neurologique Nov 2020There is an aging of the peripheral nervous system characterized by a decrease in sensory and motor nerve conduction, amplitudes of motor and above all sensory... (Review)
Review
There is an aging of the peripheral nervous system characterized by a decrease in sensory and motor nerve conduction, amplitudes of motor and above all sensory potentials, an abolition of the ankle jerk reflexes and an alteration of proprioceptive sensitivity in almost two-thirds of individuals over 65 years old. These anomalies tend to increase beyond 80 years. However, these signs of aging do not affect the quality of life of the subjects. The causes of peripheral neuropathies in the elderly differ little from those observed before age 65. Of course, hereditary causes are much less frequent, except cases with a late onset, now easily detectable, such as familial amyloidosis. In our climates and in the most developed countries, diabetes remains the most common cause, the prevalence of neuropathy increasing with age. The so-called idiopathic causes are also frequent and despite extensive investigations, nearly 20% of cases remain without etiological diagnosis, but this type of neuropathy is generally mild and not very progressive. The presence of peripheral neuropathy in the elderly can cause real problems in daily life, including the frequency of falls that can be responsible for deleterious bone damage.
Topics: Aged; Aging; Humans; Neural Conduction; Peripheral Nervous System; Peripheral Nervous System Diseases; Quality of Life
PubMed: 32980155
DOI: 10.1016/j.neurol.2019.11.007 -
Handbook of Clinical Neurology 2023Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. Unrecognized and therefore untreated,... (Review)
Review
Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. Unrecognized and therefore untreated, vasculitis of the nervous system leads to pervasive injury and disability, making this a disorder of paramount importance to all clinicians. There has been remarkable progress in the pathogenesis, diagnosis, and treatment of primary CNS and PNS vasculitides, predicated on achievement in primary systemic forms. Primary neurological vasculitides can be diagnosed with assurance after intensive evaluation that incudes tissue confirmation whenever possible. Clinicians must choose from among the available immune modulating, suppressive, and targeted immunotherapies to induce and maintain remission status and prevent relapse, unfortunately without the benefit of RCTs, and tempered by the recognition of anticipated medication side effects. It may be said that efforts to define a disease are attempts to understand the very concept of the disease. This has been especially evident in systemic and neurological disorders associated with vasculitis. For the past 100 years, since the first description of granulomatous angiitis of the brain, the CNS vasculitides have captured the attention of generations of clinical investigators around the globe to reach a better understanding of vasculitides involving the central and peripheral nervous system. Since that time it has become increasingly evident that this will necessitate an international collaborative effort.
Topics: Child; Adult; Humans; Vasculitis; Nervous System Diseases; Peripheral Nervous System
PubMed: 37562892
DOI: 10.1016/B978-0-323-98818-6.00008-X -
Nutrients Oct 2020Citicoline is a chemical compound involved in the synthesis of cell membranes. It also has other, not yet explained functions. Research on the use of citicoline is...
Citicoline is a chemical compound involved in the synthesis of cell membranes. It also has other, not yet explained functions. Research on the use of citicoline is conducted in neurology, ophthalmology, and psychiatry. Citicoline is widely available as a dietary supplement. It is often used to enhance cognitive functions. In our article, accessible databases were searched for articles regarding citicoline use in neurological diseases. This article has a systemic review form. After rejecting non-eligible reports, 47 remaining articles were reviewed. The review found that citicoline has been proven to be a useful compound in preventing dementia progression. It also enhances cognitive functions among healthy individuals and improves prognosis after stroke. In an animal model of nerve damage and neuropathy, citicoline stimulated regeneration and lessened pain. Among patients who underwent brain trauma, citicoline has an unclear clinical effect. Citicoline has a wide range of effects and could be an essential substance in the treatment of many neurological diseases. Its positive impact on learning and cognitive functions among the healthy population is also worth noting.
Topics: Animals; Brain Injuries, Traumatic; Cognition; Cytidine Diphosphate Choline; Dementia; Disease Models, Animal; Humans; Meta-Analysis as Topic; Nervous System Diseases; Neuralgia; Neurotransmitter Agents; Peripheral Nervous System; Stroke
PubMed: 33053828
DOI: 10.3390/nu12103113 -
Cell and Tissue Research Jul 2023Dorsal root ganglia (DRG) contains thousands of sensory neurons that transmit information about our external and internal environment to the central nervous system. This... (Review)
Review
Dorsal root ganglia (DRG) contains thousands of sensory neurons that transmit information about our external and internal environment to the central nervous system. This includes signals related to proprioception, temperature, and nociception. Our understanding of DRG has increased tremendously over the last 50 years and has established the DRG as an active participant in peripheral processes. This includes interactions between neurons and non-neuronal cells such as satellite glia cells and macrophages that contribute to an increasingly complex cellular environment that modulates neuronal function. Early ultrastructural investigations of the DRG have described subtypes of sensory neurons based on differences in the arrangement of organelles such as the Golgi apparatus and the endoplasmic reticulum. The neuron-satellite cell complex and the composition of the axon hillock in DRG have also been investigated, but, apart from basic descriptions of Schwann cells, ultrastructural investigations of other cell types in DRG are limited. Furthermore, detailed descriptions of key components of DRG, such as blood vessels and the capsule that sits at the intersection of the meninges and the connective tissue covering the peripheral nervous system, are lacking to date. With rising interest in DRG as potential therapeutic targets for aberrant signalling associated with chronic pain conditions, gaining further insights into DRG ultrastructure will be fundamental to understanding cell-cell interactions that modulate DRG function. In this review, we aim to provide a synopsis of the current state of knowledge on the ultrastructure of the DRG and its components, as well as to identify areas of interest for future studies.
Topics: Humans; Ganglia, Spinal; Neuroglia; Schwann Cells; Sensory Receptor Cells; Pain
PubMed: 37079097
DOI: 10.1007/s00441-023-03770-w -
Cells Jul 2020The peripheral nervous system has retained through evolution the capacity to repair and regenerate after assault from a variety of physical, chemical, or biological... (Review)
Review
The peripheral nervous system has retained through evolution the capacity to repair and regenerate after assault from a variety of physical, chemical, or biological pathogens. Regeneration relies on the intrinsic abilities of peripheral neurons and on a permissive environment, and it is driven by an intense interplay among neurons, the glia, muscles, the basal lamina, and the immune system. Indeed, extrinsic signals from the milieu of the injury site superimpose on genetic and epigenetic mechanisms to modulate cell intrinsic programs. Here, we will review the main intrinsic and extrinsic mechanisms allowing severed peripheral axons to re-grow, and discuss some alarm mediators and pro-regenerative molecules and pathways involved in the process, highlighting the role of Schwann cells as central hubs coordinating multiple signals. A particular focus will be provided on regeneration at the neuromuscular junction, an ideal model system whose manipulation can contribute to the identification of crucial mediators of nerve re-growth. A brief overview on regeneration at sensory terminals is also included.
Topics: Humans; Nerve Regeneration; Neurons; Peripheral Nervous System; Schwann Cells
PubMed: 32722089
DOI: 10.3390/cells9081768