The Timing of Oligodendrocyte Cell Death Determines the Potential of Myelin Recovery During Brain Postnatal Development
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Nervous Tissue
Nervous Tissue Prof.Prof. ZhouZhou LiLi Dept.Dept. ofof HistologyHistology andand EmbryologyEmbryology Organization:Organization: neuronsneurons (nerve(nerve cells)cells) neuroglialneuroglial cellscells Function:Function: Ⅰ Neurons 1.1. structurestructure ofof neuronneuron somasoma neuriteneurite a.a. dendritedendrite b.b. axonaxon 1.11.1 somasoma (1)(1) nucleusnucleus LocatedLocated inin thethe centercenter ofof soma,soma, largelarge andand palepale--stainingstaining nucleusnucleus ProminentProminent nucleolusnucleolus (2)(2) cytoplasmcytoplasm (perikaryon)(perikaryon) a.a. NisslNissl bodybody b.b. neurofibrilneurofibril NisslNissl’’ss bodiesbodies LM:LM: basophilicbasophilic massmass oror granulesgranules Nissl’s Body (TEM) EMEM:: RERRER,, freefree RbRb FunctionFunction:: producingproducing thethe proteinprotein ofof neuronneuron structurestructure andand enzymeenzyme producingproducing thethe neurotransmitterneurotransmitter NeurofibrilNeurofibril thethe structurestructure LM:LM: EM:EM: NeurofilamentNeurofilament micmicrotubulerotubule FunctionFunction cytoskeleton,cytoskeleton, toto participateparticipate inin substancesubstance transporttransport LipofuscinLipofuscin (3)(3) CellCell membranemembrane excitableexcitable membranemembrane ,, receivingreceiving stimutation,stimutation, fromingfroming andand conductingconducting nervenerve impulesimpules neurite: 1.2 Dendrite dendritic spine spine apparatus Function: 1.3 Axon axon hillock, axon terminal, axolemma Axoplasm: microfilament, microtubules, neurofilament, mitochondria, -
Nervous Tissue
Nervous Tissue • Controls and integrates all body activities within limits that maintain life • Three basic functions – sensing changes with sensory receptors • fullness of stomach or sun on your face – interpreting and remembering those changes – reacting to those changes with effectors • muscular contractions • glandular secretions Major Structures of the Nervous System • Brain, cranial nerves, spinal cord, spinal nerves, ganglia, enteric plexuses and sensory receptors Organization of the Nervous System • CNS is brain and spinal cord • PNS is everything else Nervous System Divisions • Central nervous system (CNS) – consists of the brain and spinal cord • Peripheral nervous system (PNS) – consists of cranial and spinal nerves that contain both sensory and motor fibers – connects CNS to muscles, glands & all sensory receptors Subdivisions of the PNS • Somatic (voluntary) nervous system (SNS) – neurons from cutaneous and special sensory receptors to the CNS – motor neurons to skeletal muscle tissue • Autonomic (involuntary) nervous systems – sensory neurons from visceral organs to CNS – motor neurons to smooth & cardiac muscle and glands • sympathetic division (speeds up heart rate) • parasympathetic division (slow down heart rate) • Enteric nervous system (ENS) – involuntary sensory & motor neurons control GI tract – neurons function independently of ANS & CNS Neurons • Functional unit of nervous system • Have capacity to produce action potentials – electrical excitability • Cell body – single nucleus with prominent nucleolus – Nissl -
Pre-Oligodendrocytes from Adult Human CNS
The Journal of Neuroscience, April 1992, 12(4): 1538-l 547 Pre-Oligodendrocytes from Adult Human CNS Regina C. Armstrong,lJ Henry H. Dorn, l,b Conrad V. Kufta,* Emily Friedman,3 and Monique E. Dubois-Dalcq’ ‘Laboratory of Viral and Molecular Pathogenesis, and %urgical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland 20892 and 3Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-3246 CNS remyelination and functional recovery often occur after Rapid and efficient neurotransmission is dependent upon the experimental demyelination in adult rodents. This has been electrical insulating capacity of the myelin sheath around axons attributed to the ability of mature oligodendrocytes and/or (reviewed in Ritchie, 1984a,b). Nerve conduction is impaired their precursor cells to divide and regenerate in response after loss of the myelin sheath and results in severe neurological to signals in demyelinating lesions. To determine whether dysfunction in human demyelinating diseases such as multiple oligodendrocyte precursor cells exist in the adult human sclerosis (MS). Remyelination can occur in the CNS of MS CNS, we have cultured white matter from patients under- patients but appears to be limited (Perier and Gregoire, 1965; going partial temporal lobe resection for intractable epilep- Prineas et al., 1984). Studies of acute MS cases have revealed sy. These cultures contained a population of process-bear- that recent demyelinating lesions can exhibit remyelination that ing cells that expressed antigens recognized by the 04 appears to correlate with the generation of new oligodendrocytes monoclonal antibody, but these cells did not express galac- (Prineas et al., 1984; Raine et al., 1988). -
Acute Reduction of Microglia Does Not Alter Axonal Injury in a Mouse Model of Repetitive Concussive Traumatic Brain Injury Rachel E
Washington University School of Medicine Digital Commons@Becker Open Access Publications 2014 Acute reduction of microglia does not alter axonal injury in a mouse model of repetitive concussive traumatic brain injury Rachel E. Bennett Washington University School of Medicine David L. Brody Washington University School of Medicine Follow this and additional works at: https://digitalcommons.wustl.edu/open_access_pubs Recommended Citation Bennett, Rachel E. and Brody, David L., ,"Acute reduction of microglia does not alter axonal injury in a mouse model of repetitive concussive traumatic brain injury." Journal of Neurotrauma.31,9. 1647-1663. (2014). https://digitalcommons.wustl.edu/open_access_pubs/4711 This Open Access Publication is brought to you for free and open access by Digital Commons@Becker. It has been accepted for inclusion in Open Access Publications by an authorized administrator of Digital Commons@Becker. For more information, please contact [email protected]. JOURNAL OF NEUROTRAUMA 31:1647–1663 (October 1, 2014) ª Mary Ann Liebert, Inc. DOI: 10.1089/neu.2013.3320 Acute Reduction of Microglia Does Not Alter Axonal Injury in a Mouse Model of Repetitive Concussive Traumatic Brain Injury Rachel E. Bennett and David L. Brody Abstract The pathological processes that lead to long-term consequences of multiple concussions are unclear. Primary mechanical damage to axons during concussion is likely to contribute to dysfunction. Secondary damage has been hypothesized to be induced or exacerbated by inflammation. The main inflammatory cells in the brain are microglia, a type of macrophage. This research sought to determine the contribution of microglia to axon degeneration after repetitive closed-skull traumatic brain injury (rcTBI) using CD11b-TK (thymidine kinase) mice, a valganciclovir-inducible model of macrophage depletion. -
Was Not Reached, However, Even After Six to Sevenhours. A
PROTEIN SYNTHESIS IN THE ISOLATED GIANT AXON OF THE SQUID* BY A. GIUDITTA,t W.-D. DETTBARN,t AND MIROSLAv BRZIN§ MARINE BIOLOGICAL LABORATORY, WOODS HOLE, MASSACHUSETTS Communicated by David Nachmansohn, February 2, 1968 The work of Weiss and his associates,1-3 and more recently of a number of other investigators,4- has established the occurrence of a flux of materials from the soma of neurons toward the peripheral regions of the axon. It has been postulated that this mechanism would account for the origin of most of the axonal protein, although the time required to cover the distance which separates some axonal tips from their cell bodies would impose severe delays.4 On the other hand, a number of observations7-9 have indicated the occurrence of local mechanisms of synthesis in peripheral axons, as suggested by the kinetics of appearance of individual proteins after axonal transection. In this paper we report the incorporation of radioactive amino acids into the protein fraction of the axoplasm and of the axonal envelope obtained from giant axons of the squid. These axons are isolated essentially free from small fibers and connective tissue, and pure samples of axoplasm may be obtained by extru- sion of the axon. Incorporation of amino acids into axonal protein has recently been reported using systems from mammals'0 and fish."I Materials and Methods.-Giant axons of Loligo pealii were dissected and freed from small fibers: they were tied at both ends. Incubations were carried out at 18-20° in sea water previously filtered through Millipore which contained 5 mM Tris pH 7.8 and 10 Muc/ml of a mixture of 15 C'4-labeled amino acids (New England Nuclear Co., Boston, Mass.). -
(Caspr) and Contactin Form a Complex That Is Targeted to the Paranodal Junctions During Myelination
The Journal of Neuroscience, November 15, 2000, 20(22):8354–8364 Contactin-Associated Protein (Caspr) and Contactin Form a Complex That Is Targeted to the Paranodal Junctions during Myelination Jose C. Rios,1 Carmen V. Melendez-Vasquez,1 Steven Einheber,1 Marc Lustig,2 Martin Grumet,2 John Hemperly,5 Elior Peles,6 and James L. Salzer1,3,4 Departments of 1Cell Biology, 2Pharmacology, 3Neurology, and the 4Kaplan Cancer Center, New York University School of Medicine, New York, New York 10016, 5BD Technologies, Research Triangle Park, North Carolina 27709, and 6Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel Specialized paranodal junctions form between the axon and the associated specifically with Caspr in the paranodes, whereas a closely apposed paranodal loops of myelinating glia. They are higher-molecular-weight form of contactin, not associated with interposed between sodium channels at the nodes of Ranvier Caspr, is present in central nodes of Ranvier. These results and potassium channels in the juxtaparanodal regions; their suggest that the targeting of contactin to different axonal do- precise function and molecular composition have been elusive. mains may be determined, in part, via its association with Caspr. We previously reported that Caspr (contactin-associated protein) Treatment of myelinating cocultures of Schwann cells and neu- is a major axonal constituent of these junctions (Einheber et al., rons with RPTP–Fc, a soluble construct containing the carbonic 1997). We now report that contactin colocalizes and forms a cis anhydrase domain of the receptor protein tyrosine phosphatase complex with Caspr in the paranodes and juxtamesaxon. -
Fundamentals of Nervous System and Nervous Tissue
Fundamentals of Nervous System and Nervous Tissue Chapter 12 Nervous System The nervous system is the main system to communicate and coordinate body activities by sending electrical impulses. Nervous system forms a communication network in whole body. Endocrine system communicates through chemical messengers – hormones. 12 pairs of Cranial nerves arise from brain Brain (Part of PNS) Central NS 31 pairs of spinal nerves arise from spinal Spinal nerve cord nerve cord (Part of PNS) Somatic sensory Afferent Division Visceral sensory Peripheral NS Somatic NS Efferent Division Sympathetic Autonomic NS Parasympathetic Neuron A neuron has a cell body. Many smaller branched appendages are called Dendrites. Dendrites bring in information (nerve impulse) to the cell body. A single longer appendage is called Axon. It takes information away from cell body. It branches at the end into terminal knobs. A terminal knob secretes a chemical called Neurotransmitter in the gap to the next neuron or muscle membrane. 3-types of neurons (on basis of function) Specialized nerve cells are called Neurons. Sensory neurons bring information from sense organs like eyes to CNS. Sensory = Affrent. Somatic Sensory = coming from body wall - skin, muscles and joints; Visceral Sensroy = coming from internal organs - viscera Motor neurons take information from CNS to effectors like muscles or glands. Motor = Effrent. Somatic Motor – going to skeletal muscles and Visceral Motor – going to smooth or cardiac muscles. Inter-neurons receive information from sensory neurons and -
11 Introduction to the Nervous System and Nervous Tissue
11 Introduction to the Nervous System and Nervous Tissue ou can’t turn on the television or radio, much less go online, without seeing some- 11.1 Overview of the Nervous thing to remind you of the nervous system. From advertisements for medications System 381 Yto treat depression and other psychiatric conditions to stories about celebrities and 11.2 Nervous Tissue 384 their battles with illegal drugs, information about the nervous system is everywhere in 11.3 Electrophysiology our popular culture. And there is good reason for this—the nervous system controls our of Neurons 393 perception and experience of the world. In addition, it directs voluntary movement, and 11.4 Neuronal Synapses 406 is the seat of our consciousness, personality, and learning and memory. Along with the 11.5 Neurotransmitters 413 endocrine system, the nervous system regulates many aspects of homeostasis, including 11.6 Functional Groups respiratory rate, blood pressure, body temperature, the sleep/wake cycle, and blood pH. of Neurons 417 In this chapter we introduce the multitasking nervous system and its basic functions and divisions. We then examine the structure and physiology of the main tissue of the nervous system: nervous tissue. As you read, notice that many of the same principles you discovered in the muscle tissue chapter (see Chapter 10) apply here as well. MODULE 11.1 Overview of the Nervous System Learning Outcomes 1. Describe the major functions of the nervous system. 2. Describe the structures and basic functions of each organ of the central and peripheral nervous systems. 3. Explain the major differences between the two functional divisions of the peripheral nervous system. -
Dorsal Root Injury—A Model for Exploring Pathophysiology and Therapeutic Strategies in Spinal Cord Injury
cells Review Dorsal Root Injury—A Model for Exploring Pathophysiology and Therapeutic Strategies in Spinal Cord Injury Håkan Aldskogius * and Elena N. Kozlova Laboratory of Regenertive Neurobiology, Biomedical Center, Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden; [email protected] * Correspondence: [email protected] Abstract: Unraveling the cellular and molecular mechanisms of spinal cord injury is fundamental for our possibility to develop successful therapeutic approaches. These approaches need to address the issues of the emergence of a non-permissive environment for axonal growth in the spinal cord, in combination with a failure of injured neurons to mount an effective regeneration program. Experimental in vivo models are of critical importance for exploring the potential clinical relevance of mechanistic findings and therapeutic innovations. However, the highly complex organization of the spinal cord, comprising multiple types of neurons, which form local neural networks, as well as short and long-ranging ascending or descending pathways, complicates detailed dissection of mechanistic processes, as well as identification/verification of therapeutic targets. Inducing different types of dorsal root injury at specific proximo-distal locations provide opportunities to distinguish key components underlying spinal cord regeneration failure. Crushing or cutting the dorsal root allows detailed analysis of the regeneration program of the sensory neurons, as well as of the glial response at the dorsal root-spinal cord interface without direct trauma to the spinal cord. At the same time, a lesion at this interface creates a localized injury of the spinal cord itself, but with an initial Citation: Aldskogius, H.; Kozlova, neuronal injury affecting only the axons of dorsal root ganglion neurons, and still a glial cell response E.N. -
The “Road Map”
PRACTICAL ROADMAP NERVOUS TISSUE DR N GRAVETT NEURONS • MOTOR • SENSORY Anterior (ventral) horn Dorsal root of spinal of spinal cord cord Multipolar Pseudounipolar ANTERIOR HORN CELLS • Slide 64 Spinal Cord (vervet monkey) Stain: Kluver and Berrera Technique NOTE: with this technique, myelin stains dark blue and basophilic substances such as rER and nuclei stain violet. In this case we use “blue” and “purple” to describe the staining and not eosinophilic and basophilic. SPINAL CORD Anterior Ventral Horn Arachnoid Ventricle Pia Mater Grey Matter White Matter Posterior Horn Dura Mater Dorsal ANTERIOR HORN CELL Neuropil Cell Body Dendrite Vesicular Nucleus Nucleolus Nucleus of Nissl Bodies Neuroglial Cell ANTERIOR HORN CELL Neuropil Cell Body Vesicular Nucleus Nucleolus Nissl Body Nucleus of Neuroglial Cell Dendrite Nissl Body Axon Hillock Axon SPINAL (DORSAL ROOT) GANGLION CELLS • Slide 62 Spinal Ganglion Stain: H&E NOTE: The spinal ganglion is also known as the dorsal root ganglia and contains pseudounipolar neuron cell bodies. SPINAL (DORSAL ROOT) GANGLIA Cell Bodies Processes (Axons and Dendrites) SPINAL (DORSAL ROOT) GANGLIA Cell Bodies Processes (Axons and Dendrites) NOTE: The neuronal cell bodies of the dorsal root ganglia are “clumped” together, and one cannot see any processes entering or leaving the cell bodies. The processes (axons and dendrites) are seen towards the edge/periphery of the group of cell bodies. SPINAL (DORSAL ROOT) GANGLIA Satellite cells (arranged in ring like fashion around the cell body) Cell Body Nucleolus Vesicular Fine Granular Nucleus Nissl Substance Nucleus of Satellite cell PERIPHERAL BRANCH OF A SPINAL NERVE • Slide 32 Median Nerve Stain: Mallory’s Technique NOTE: Three dyes are used in Mallory’s technique, which results in collagen fibres (such as connective tissue) staining blue, the “neurokeratin” staining red, and nuclei staining reddish-orange PERIPHERAL NERVE Myelinated Axons Vein L.S. -
Chapter 22 – Neuromuscular Physiology and Pharmacology J. A. Jeevendra Martyn
Chapter 22 – Neuromuscular Physiology and Pharmacology J. A. Jeevendra Martyn The physiology of neuromuscular transmission could be analyzed and understood at the most simple level by using the classic model of nerve signaling to muscle through the acetylcholine receptor. The mammalian neuromuscular junction is the prototypical and most extensively studied synapse. Research has provided more detailed information on the processes that, within the classic scheme, can modify neurotransmission and response to drugs. One example of this is the role of qualitative or quantitative changes in acetylcholine receptors modifying neurotransmission and response to drugs.[1][2] In myasthenia gravis, for example, the decrease in acetylcholine receptors results in decreased efficiency of neurotransmission (and therefore muscle weakness)[3] and altered sensitivity to neuromuscular relaxants.[1][2] Another example is the importance of nerve-related (prejunctional) changes that alter neurotransmission and response to drugs.[1][4] At still another level is the evidence that muscle relaxants act in ways that are not encompassed by the classic scheme of unitary site of action. The observation that muscle relaxants can have prejunctional effects[5] or that some nondepolarizers can also have agonist-like stimulatory actions on the receptor[6] while others have effects not explainable by purely postsynaptic events[7] has provided new insights into some previously unexplained observations. Although this multifaceted action-response scheme makes the physiology and -
Neuromuscular Junctions in the Body Wall Muscles of the Earthworm, Lumbricus Terrestris Linn
J. Cell Set, 7, 263-271 (1970) 263 Printed in Great Britain NEUROMUSCULAR JUNCTIONS IN THE BODY WALL MUSCLES OF THE EARTHWORM, LUMBRICUS TERRESTRIS LINN. P. J. MILL AND M. F. KNAPP Department of Zoology, University of Leeds, England SUMMARY The fine structure of the neuromuscular junctions in the body wall muscles of the earthworm 13 described. The segmental nerves send branches into the muscle layers. Axons in the nerve branches contain numerous synaptic vesicles and contact is established between these axons and muscle fibres or muscle tails; the latter may extend for a considerable distance from the muscle fibre. The cleft between the axolemma and sarcolemma is 85-120 nm wide and con- tains basement membrane material. At intervals small aggregations of electron-dense material are attached to the axonal membrane and synaptic vesicles are associated with these. The sarcolemma bears rather larger masses of dense material and is also specialized extracellularly. INTRODUCTION The earthworm's body wall muscles are innervated by the segmental nerves. There are about 300 motor fibres in the segmental nerves of a typical segment of the earth- worm Pherettma communissima (Ogawa, 1939); these innervate at least 120000 muscle fibres. The axons give off many branches to the muscles and their endings are den- dritic in form in fully grown worms but bud-like in young worms. According to Retzius (1892 a), finely branching motor fibres ramify in the muscles of Lumbricus, terminating as free endings which are like knotted threads in appearance. His figures indicate both multiterminal and polyneuronal innervation. Smallwood (1926) in an investigation of Lumbricus terrestris, noted that in addition to fine branching nerve fibres with knob-like endings, which he considered to be sensory, there is another type of ending characterized by a cluster of branches, but also with knob-like terminals; he thought that these were motor in function.