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Development (Cambridge, England) May 2023The peripheral nervous system (PNS) represents a highly heterogeneous entity with a broad range of functions, ranging from providing communication between the brain and...
The peripheral nervous system (PNS) represents a highly heterogeneous entity with a broad range of functions, ranging from providing communication between the brain and the body to controlling development, stem cell niches and regenerative processes. According to the structure and function, the PNS can be subdivided into sensory, motor (i.e. the nerve fibers of motor neurons), autonomic and enteric domains. Different types of neurons correspond to these domains and recent progress in single-cell transcriptomics has enabled the discovery of new neuronal subtypes and improved the previous cell-type classifications. The developmental mechanisms generating the domains of the PNS reveal a range of embryonic strategies, including a variety of cell sources, such as migratory neural crest cells, placodal neurogenic cells and even recruited nerve-associated Schwann cell precursors. In this article, we discuss the diversity of roles played by the PNS in our body, as well as the origin, wiring and heterogeneity of every domain. We place a special focus on the most recent discoveries and concepts in PNS research, and provide an outlook of future perspectives and controversies in the field.
Topics: Peripheral Nervous System; Neurogenesis; Neural Crest; Schwann Cells; Motor Neurons
PubMed: 37170957
DOI: 10.1242/dev.201164 -
Handbook of Clinical Neurology 2013The nervous system is divided into the central nervous system (CNS) composed of the brain, the brainstem, the cerebellum, and the spinal cord and the peripheral nervous... (Review)
Review
The nervous system is divided into the central nervous system (CNS) composed of the brain, the brainstem, the cerebellum, and the spinal cord and the peripheral nervous system (PNS) made up of the different nerves arising from the CNS. The PNS is divided into the cranial nerves III to XII supplying the head and the spinal nerves that supply the upper and lower limbs. The general anatomy of the PNS is organized according to the arrangement of the fibers along the rostro-caudal axis. The control of the development of the PNS has been unravelled during the last 30 years. Motor nerves arise from the ventral neural tube. This ventralization is induced by morphogenetic molecules such as sonic hedgehog. In contrast, the sensory elements of the PNS arise from a specific population of cells originating from the roof of the neural tube, namely the neural crest. These cells give rise to the neurons of the dorsal root ganglia, the autonomic ganglia and the paraganglia including the adrenergic neurons of the adrenals. Furthermore, the supportive glial Schwann cells of the PNS originate from the neural crest cells. Growth factors as well as myelinating proteins are involved in the development of the PNS.
Topics: Animals; Humans; Neural Crest; Neuroglia; Neurons; Peripheral Nervous System
PubMed: 23931773
DOI: 10.1016/B978-0-444-52902-2.00003-5 -
Journal of Neuroscience Methods Dec 2020How rich functionality emerges from the rather invariant structural architecture of the peripheral autonomic nervous system remains one of the major mysteries in... (Review)
Review
How rich functionality emerges from the rather invariant structural architecture of the peripheral autonomic nervous system remains one of the major mysteries in neuroscience. The high incidence of patients with neural circuit-related autonomic nervous system diseases highlights the importance of fundamental research, among others with neurotracing methods, into autonomic neuron functionality. Due to the emergence of neurotropic virus-based tracing techniques in recent years the access to neuronal connectivity in the peripheral autonomic nervous system has greatly been improved. This review is devoted to the anatomical distribution of neural circuits in the periphery of the autonomous nervous system and to the interaction between the autonomic nervous system and vital peripheral organs or tissues. The experimental evidence available at present has greatly expanded our understanding of autonomic peripheral nervous system neurons.
Topics: Autonomic Nervous System; Humans; Interneurons; Neurons; Peripheral Nervous System; Viruses
PubMed: 32979424
DOI: 10.1016/j.jneumeth.2020.108958 -
Annual Review of Cell and Developmental... Oct 2019Molecular cross talk between the nervous and vascular systems is necessary to maintain the correct coupling of organ structure and function. Molecular pathways shared by... (Review)
Review
Molecular cross talk between the nervous and vascular systems is necessary to maintain the correct coupling of organ structure and function. Molecular pathways shared by both systems are emerging as major players in the communication of the neuronal compartment with the endothelium. Here we review different aspects of this cross talk and how vessels influence the development and homeostasis of the nervous system. Beyond the classical role of the vasculature as a conduit to deliver oxygen and metabolites needed for the energy-demanding neuronal compartment, vessels emerge as powerful signaling systems that control and instruct a variety of cellular processes during the development of neurons and glia, such as migration, differentiation, and structural connectivity. Moreover, a broad spectrum of mild to severe vascular dysfunctions occur in various pathologies of the nervous system, suggesting that mild structural and functional changes at the neurovascular interface may underlie cognitive decline in many of these pathological conditions.
Topics: Animals; Blood Vessels; Cell Differentiation; Cell Movement; Central Nervous System; Homeostasis; Humans; Nervous System Diseases; Neuroglia; Neurons; Neurovascular Coupling; Peripheral Nervous System
PubMed: 31590587
DOI: 10.1146/annurev-cellbio-100818-125142 -
International Journal of Molecular... Nov 2020Peripheral neuropathy (PN) refers to many conditions involving damage to the peripheral nervous system (PNS). Usually, PN causes weakness, numbness and pain and is the... (Review)
Review
Peripheral neuropathy (PN) refers to many conditions involving damage to the peripheral nervous system (PNS). Usually, PN causes weakness, numbness and pain and is the result of traumatic injuries, infections, metabolic problems, inherited causes, or exposure to chemicals. Despite the high prevalence of PN, available treatments are still unsatisfactory. Neuroactive steroids (i.e., steroid hormones synthesized by peripheral glands as well as steroids directly synthesized in the nervous system) represent important physiological regulators of PNS functionality. Data obtained so far and here discussed, indeed show that in several experimental models of PN the levels of neuroactive steroids are affected by the pathology and that treatment with these molecules is able to exert protective effects on several PN features, including neuropathic pain. Of note, the observations that neuroactive steroid levels are sexually dimorphic not only in physiological status but also in PN, associated with the finding that PN show sex dimorphic manifestations, may suggest the possibility of a sex specific therapy based on neuroactive steroids.
Topics: Animals; Humans; Models, Biological; Neuroprotective Agents; Neurosteroids; Peripheral Nervous System; Peripheral Nervous System Diseases
PubMed: 33256238
DOI: 10.3390/ijms21239000 -
Toxicologic Pathology Jan 2020This review illustrates common lesions of peripheral nerve myelinated fibers that occur in toxic neuropathy. These distinctive structural changes help to define the site... (Review)
Review
This review illustrates common lesions of peripheral nerve myelinated fibers that occur in toxic neuropathy. These distinctive structural changes help to define the site of toxicant activity and thus predict the course of neurotoxic disease and recovery. Neuronopathy is the condition where the primary injury is directed to the neuronal cell body giving rise to a peripheral nerve axon. Axonopathy occurs when the axon is the primary target, and myelinopathy develops where the Schwann cell and/or myelin sheath is the primary target; these conditions can be discriminated early during the course of nerve fiber degeneration, but reciprocal influences between axon and myelin result in degeneration of both structures late in the disease.
Topics: Animals; Axons; Myelin Sheath; Nerve Degeneration; Nerve Fibers, Myelinated; Neurons; Peripheral Nerves; Peripheral Nervous System
PubMed: 30722748
DOI: 10.1177/0192623319826068 -
International Journal of Molecular... Jun 2020We studied telocytes/CD34+ stromal cells in the normal and pathological peripheral nervous system (PNS), for which we reviewed the literature and contributed our... (Review)
Review
We studied telocytes/CD34+ stromal cells in the normal and pathological peripheral nervous system (PNS), for which we reviewed the literature and contributed our observations under light and electron microscopy in this field. We consider the following aspects: (A) general characteristics of telocytes and the terminology used for these cells (e.g., endoneurial stromal cells) in PNS; (B) the presence, characteristics and arrangement of telocytes in the normal PNS, including (i) nerve epi-perineurium and endoneurium (e.g., telopodes extending into the endoneurial space); (ii) sensory nerve endings (e.g., Meissner and Pacinian corpuscles, and neuromuscular spindles); (iii) ganglia; and (iv) the intestinal autonomic nervous system; (C) the telocytes in the pathologic PNS, encompassing (i) hyperplastic neurogenic processes (neurogenic hyperplasia of the appendix and gallbladder), highly demonstrative of telocyte characteristics and relations, (ii) PNS tumours, such as neurofibroma, schwannoma, granular cell tumour and nerve sheath myxoma, and interstitial cell of Cajal-related gastrointestinal stromal tumour (GIST), (iii) tumour-invaded nerves and (iv) traumatic, metabolic, degenerative or genetic neuropathies, in which there are fewer studies on telocytes, e.g., neuroinflammation and nerves in undescended testicles (cryptorchidism), Klinefelter syndrome, crush injury, mucopolysaccharidosis II (Hunter's syndrome) and Charcot-Marie-Tooth disease.
Topics: Animals; Biomarkers; Disease Susceptibility; Humans; Immunohistochemistry; Nerve Endings; Peripheral Nervous System; Peripheral Nervous System Diseases; Telocytes
PubMed: 32560571
DOI: 10.3390/ijms21124320 -
Current Pain and Headache Reports Jun 2017Our goal is to examine the processes-both central and peripheral-that underlie the development of peripherally-induced neuropathic pain (pNP) and to highlight recent... (Review)
Review
PURPOSE OF REVIEW
Our goal is to examine the processes-both central and peripheral-that underlie the development of peripherally-induced neuropathic pain (pNP) and to highlight recent evidence for mechanisms contributing to its maintenance. While many pNP conditions are initiated by damage to the peripheral nervous system (PNS), their persistence appears to rely on maladaptive processes within the central nervous system (CNS). The potential existence of an autonomous pain-generating mechanism in the CNS creates significant implications for the development of new neuropathic pain treatments; thus, work towards its resolution is crucial. Here, we seek to identify evidence for PNS and CNS independently generating neuropathic pain signals.
RECENT FINDINGS
Recent preclinical studies in pNP support and provide key details concerning the role of multiple mechanisms leading to fiber hyperexcitability and sustained electrical discharge to the CNS. In studies regarding central mechanisms, new preclinical evidence includes the mapping of novel inhibitory circuitry and identification of the molecular basis of microglia-neuron crosstalk. Recent clinical evidence demonstrates the essential role of peripheral mechanisms, mostly via studies that block the initially damaged peripheral circuitry. Clinical central mechanism studies use imaging to identify potentially self-sustaining infra-slow CNS oscillatory activity that may be unique to pNP patients. While new preclinical evidence supports and expands upon the key role of central mechanisms in neuropathic pain, clinical evidence for an autonomous central mechanism remains relatively limited. Recent findings from both preclinical and clinical studies recapitulate the critical contribution of peripheral input to maintenance of neuropathic pain. Further clinical investigations on the possibility of standalone central contributions to pNP may be assisted by a reconsideration of the agreed terms or criteria for diagnosing the presence of central sensitization in humans.
Topics: Central Nervous System; Humans; Neuralgia; Neurons; Peripheral Nervous System
PubMed: 28432601
DOI: 10.1007/s11916-017-0629-5 -
Regenerative Medicine Jun 2021There exists a dichotomy in regenerative capacity between the PNS and CNS, which poses the question - where do cranial nerves fall? Through the discussion of the various... (Review)
Review
There exists a dichotomy in regenerative capacity between the PNS and CNS, which poses the question - where do cranial nerves fall? Through the discussion of the various cells and processes involved in axonal regeneration, we will evaluate whether the assumption that cranial nerve regeneration is analogous to peripheral nerve regeneration is valid. It is evident from this review that much remains to be clarified regarding both PNS and CNS regeneration. Furthermore, it is not clear if cranial nerves follow the PNS model, CNS model or possess an alternative novel regenerative process altogether. Future research should continue to focus on elucidating how cranial nerves regenerate; and the various cellular interactions, molecules and pathways involved.
Topics: Axons; Central Nervous System; Cranial Nerves; Nerve Regeneration; Peripheral Nerves; Peripheral Nervous System; Schwann Cells
PubMed: 34075805
DOI: 10.2217/rme-2020-0096 -
Critical Reviews in Biochemistry and... Feb 2020Optogenetics has recently gained recognition as a biological technique to control the activity of cells using light stimulation. Many studies have applied optogenetics... (Review)
Review
Optogenetics has recently gained recognition as a biological technique to control the activity of cells using light stimulation. Many studies have applied optogenetics to cell lines in the central nervous system because it has the potential to elucidate neural circuits, treat neurological diseases and promote nerve regeneration. There have been fewer studies on the application of optogenetics in the peripheral nervous system. This review introduces the basic principles and approaches of optogenetics and summarizes the physiology and mechanism of opsins and how the technology enables bidirectional control of unique cell lines with superior spatial and temporal accuracy. Further, this review explores and discusses the therapeutic potential for the development of optogenetics and its capacity to revolutionize treatment for refractory epilepsy, depression, pain, and other nervous system disorders, with a focus on neural regeneration, especially in the peripheral nervous system. Additionally, this review synthesizes the latest preclinical research on optogenetic stimulation, including studies on non-human primates, summarizes the challenges, and highlights future perspectives. The potential of optogenetic stimulation to optimize therapy for peripheral nerve injuries (PNIs) is also highlighted. Optogenetic technology has already generated exciting, preliminary evidence, supporting its role in applications to several neurological diseases, including PNIs.
Topics: Animals; Central Nervous System; Humans; Nervous System Diseases; Optogenetics; Peripheral Nervous System
PubMed: 32070147
DOI: 10.1080/10409238.2020.1726279