Cells of the Nervous System

The nervous system is made up of neurons and glia that derive from neuroectoderm. Since neurons are terminally differentiated and do not divide, primary intracranial tumors do not arise from mature neurons. Tumors outside the nervous system may metastasize inside the brain or may release a substance that negatively affects brain function, termed paraneoplastic disease. Neurons receive information through synaptic inputs onto dendrites and soma and send information to other cells via a synaptic terminal. Most neurons send information to faraway locations and for this, an axon that connects the soma to synaptic terminals is required. Glial cells wrap axons in myelin, which speeds up information transfer. Axonal transport is necessary to maintain neuronal function and health across the long distances separating synaptic terminals and somata. A common mechanism of neurodegeneration arises from impairments in axonal transport that lead to protein aggregation and neuronal death.

Peripheral Sympathetic Nervous System

ULTRASTRUCTURAL IDENTIFICATION OF CATECHOLAMINE-CONTAINING CENTRAL SYNAPTIC TERMINALS

Journal of Histochemistry & Cytochemistry ◽

10.1177/21.4.333 ◽

1973 ◽

Vol 21 (4) ◽

pp. 333-348 ◽

Cited By ~ 67

Author(s):

FLOYD E. BLOOM

Keyword(s):

Nervous System ◽

Nerve Terminals ◽

Synaptic Terminals ◽

Direct Localization ◽

Sympathetic Nervous ◽

Neurotransmitter Substances ◽

6 Hydroxydopamine ◽

The Brain ◽

Selective Accumulation ◽

Cytochemical methods for the localization of central catecholamine-containing synaptic terminals have been developed from an extensive foundation of biochemical work and from extrapolation of results on the peripheral sympathetic nervous system. Direct localization of catecholamines in central nerve terminals in some parts of the brain can now be obtained by fixation with permanganates. More broadly applicable, but less direct localizing methods depend upon selective accumulation of tritiated catecholamines for autoradiography or the accumulation of reactive catecholamine congeners which act as markers with conventional fixation. The pattern of acute degenerative changes which result after treatment with 6-hydroxydopamine can also be used to provide an indirect localization of the terminals which had stored catecholamines. When the results of each of the methods are combined, the present techniques indicate that catecholamine-containing terminals in the brain can be identified more confidently than any other system of neurotransmitter substances. Nevertheless, there is considerable need for future cytochemical innovation.

Neurochemical Systems in the Central Nervous System

Neurobiology of Mental Illness ◽

10.1093/med/9780199934959.003.0002 ◽

2013 ◽

pp. 12-26

Author(s):

Ariel Y. Deutch ◽

Robert H. Roth

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Psychiatric Disorders ◽

Neurotrophic Factors ◽

Drugs Of Abuse ◽

Large Majority ◽

System P ◽

Target Neuron ◽

Chapter 2 describes the neurochemical organization of the brain. It summarizes the diverse types of molecules that neurons in the brain use as neurotransmitters and neurotrophic factors, and how these molecules are synthesized and metabolized. The chapter also presents the array of receptor proteins through which these molecules regulate target neuron functioning and the reuptake proteins that generally terminate the neurotransmitter signal. Today a large majority of all drugs used to treat psychiatric disorders, as well as most drugs of abuse, still have as their initial targets proteins involved directly in neurotransmitter function.

In and Out of the Central Nervous System

10.1093/med/9780190614966.003.0007 ◽

2016 ◽

Author(s):

Michael J. Aminoff

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Experimental Approach ◽

Cranial Nerves ◽

Motor Functions ◽

System P ◽

Experimental Findings ◽

In 1811, Bell had printed privately a monograph titled Idea of a New Anatomy of the Brain. In it, Bell correctly showed that the anterior but not the posterior roots had motor functions. François Magendie subsequently showed that the anterior roots were motor, and the posterior roots were sensory. This led to a dispute about priority during which Bell republished some of his early work with textual alterations to support his claims. Bell was involved in a similar dispute with Herbert Mayo concerning the separate functions of the fifth (sensory) and seventh (motor) cranial nerves, and Mayo today is a forgotten man. In both instances, Bell deserves credit for the concepts and initial experimental approach, and Magendie and Mayo deserve credit for obtaining and correctly interpreting the definitive experimental findings.

History of Human Immunodeficiency Virus Infection and the Nervous System

10.1093/med/9780199937837.003.0146 ◽

2017 ◽

Author(s):

Avindra Nath

Keyword(s):

Human Immunodeficiency Virus ◽

Nervous System ◽

Hiv Infection ◽

System P ◽

Clinical Syndromes ◽

Tremendous Progress ◽

Immunodeficiency Virus ◽

History Of ◽

The Brain ◽

First Descriptions

It has been nearly three decades since the first descriptions of the neurological comploications of HIV infection. During this period of time there has been tremendous progress in defining the clinical syndromes, modes of diagnosis, detailed pathophysiology and modes of treatment. Many of the dreaded complications are now manageable particularly if diagnosed early. However, neurocognitive impairment associated with HIV infection still remains a significant cause of morbidity and much is needed to control; the effects of the virus on the brain and for the eventual eradication of the virus from the brain reservoir.

Stochastic, structural and functional factors influencing AMPA and NMDA synaptic response variability: a review

Neuronal Signaling ◽

10.1042/ns20160051 ◽

2017 ◽

Vol 1 (3) ◽

Cited By ~ 3

Author(s):

Vito Di Maio ◽

Francesco Ventriglia ◽

Silvia Santillo

Keyword(s):

Nervous System ◽

Synaptic Transmission ◽

Learning And Memory ◽

Information Transfer ◽

Basic Mechanism ◽

Response Variability ◽

Synaptic Response ◽

Factors Influencing ◽

Functional Factors ◽

Synaptic transmission is the basic mechanism of information transfer between neurons not only in the brain, but along all the nervous system. In this review we will briefly summarize some of the main parameters that produce stochastic variability in the synaptic response. This variability produces different effects on important brain phenomena, like learning and memory, and, alterations of its basic factors can cause brain malfunctioning.

Introduction to the Nervous System

10.1093/med/9780190237493.003.0001 ◽

2017 ◽

Author(s):

Peggy Mason

Keyword(s):

Spinal Cord ◽

Nervous System ◽

The Body ◽

Conscious Awareness ◽

Sensory Stimuli ◽

System P ◽

Brainstem Stroke ◽

Primary Deficit ◽

The primary regions and principal functions of the central nervous system are introduced through the story of Jean-Dominique Bauby who became locked in after suffering a brainstem stroke. Bauby blinked out his story of locked-in syndrome one letter at a time. The primary deficit of locked-in syndrome is in voluntary movement because pathways from the brain to motoneurons in the brainstem and spinal cord are interrupted. Perception is also disturbed as pathways responsible for transforming sensory stimuli into conscious awareness are interrupted as they ascend through the brainstem into the forebrain. Homeostasis, through which the brain keeps the body alive, is also adversely affected in locked-in syndrome because it depends on the brain, spinal cord and autonomic nervous system. Abstract functions such as memory, language, and emotion depend fully on the forebrain and are intact in locked-in syndrome, as clearly evidenced by Bauby’s eloquent words.

The Organization of the Nervous System

10.1093/med/9780190614966.003.0008 ◽

2016 ◽

Author(s):

Michael J. Aminoff

Keyword(s):

Nervous System ◽

Peripheral Nerves ◽

Nerve Fibers ◽

Sense Organs ◽

Nerve Roots ◽

Long Thoracic Nerve ◽

System P ◽

Health And Disease ◽

To Receive ◽

Bell came up with a number of original concepts concerning the organization and operation of the nervous system in health and disease. The focus of Bell’s 1811 book was the brain, not the nerve roots. Bell suggested that parts of the brain differ in function; peripheral nerves are composed of nerve fibers with different functions; nerves conduct only in one direction; sense organs are specialized to receive only one form of sensory stimulus; and perception depends on the part of the brain activated. In later publications, he described a sixth (muscle or proprioceptive) sense and the circle of the nerves subserving it; movement and reciprocal innervation; and the long thoracic nerve (Bell’s nerve).

Astroglial contribution to tau-dependent neurodegeneration

Biochemical Journal ◽

10.1042/bcj20190506 ◽

2019 ◽

Vol 476 (22) ◽

pp. 3493-3504 ◽

Cited By ~ 3

Author(s):

Marta Sidoryk-Węgrzynowicz ◽

Lidia Strużyńska

Keyword(s):

Nervous System ◽

Synaptic Transmission ◽

Neurofibrillary Tangles ◽

Neuronal Survival ◽

Critical Role ◽

Proper Function ◽

Neuronal Dysfunction ◽

Neuronal Function ◽

Glutamate Homeostasis ◽

Astrocytes, by maintaining an optimal environment for neuronal function, play a critical role in proper function of mammalian nervous system. They regulate synaptic transmission and plasticity and protect neurons against toxic insults. Astrocytes and neurons interact actively via glutamine-glutamate cycle (GGC) that supports neuronal metabolic demands and neurotransmission. GGC deficiency may be involved in different diseases of the brain, where impaired astrocytic control of glutamate homeostasis contributes to neuronal dysfunction. This includes tau-dependent neurodegeneration, where astrocytes lose key molecules involved in regulation of glutamate/glutamine homeostasis, neuronal survival and synaptogenesis. Astrocytic dysfunction in tauopathy appears to precede neurodegeneration and overt tau neuropathology such as phosphorylation, aggregation and formation of neurofibrillary tangles. In this review, we summarize recent studies demonstrating that activation of astrocytes is strictly associated with neurodegenerative processes including those involved in tau related pathology. We propose that astrocytic dysfunction, by disrupting the proper neuron-glia signalling early in the disease, significantly contributes to tauopathy pathogenesis.

Why and How Do We Hurt?

All About Fibromyalgia ◽

10.1093/oso/9780195147537.003.0010 ◽

2002 ◽

Author(s):

Daniel J. Wallace ◽

Janice Brock Wallace

Keyword(s):

Spinal Cord ◽

Nervous System ◽

Clinical Situation ◽

The Body ◽

Sensory Pathways ◽

System P ◽

Chronic Pain Patients ◽

Pain Patients ◽

A fibromyalgia patient frequently complains of pain. The pain of fibromyalgia is different from that of a headache, stomach cramp, toothache, or swollen joint. It has been described as a type of stiffness or aching, often associated with spasm. Unlike the other pains mentioned above, fibromyalgia pain responds poorly to aspirin, acetaminophen (Tylenol), or ibuprofen (Advil, Motrin). In fact, studies have suggested that even narcotics such as morphine are minimally beneficial in ameliorating fibromyalgia pain. Why is it that fibromyalgia patients can take codeine, Darvon, Vicodin, or even Demerol for musculoskeletal aches and have only a slight response? What produces “pain without purpose”? In this chapter, we’ll explore what makes fibromyalgia a pain amplification syndrome. Why does the patient hurt in places where there was often no injury and all laboratory tests are normal? What creates what doctors call allodynia, or a clinical situation that results in pain from a stimulus (such as light touch) that normally should not be painful? Fibromyalgia is a form of chronic, widespread allodynia, as well as sustained hyperalgesia, or greater sensitivity than would be expected to an adverse stimulus. The nervous system consists of several components. The brain and spinal cord comprise the central nervous system. Nerves leaving the spinal cord that tell us to move our arms or legs are part of the “motor” aspects of the peripheral nervous system. Additionally, all sorts of information about touch, taste, chemicals, and pressure are relayed through “sensory” pathways back to the spinal cord, where they are processed and sent up to the brain for a response. The autonomic nervous system consists of specialized peripheral nerves. Fibromyalgia is a disorder characterized by an inappropriate neuromuscular reaction that leads to chronic pain. Patients with fibromyalgia usually react normally to acute pain. Our current concepts of the way the body responds to chronic painful stimuli stem from the gate theory, first proposed by Ronald Melzack and Patrick Wall in 1965. Nerve “wires” go from the periphery to the dorsal horn of the spinal cord. These wires are modulated by feedback loops within the nervous system.

Signaling in the Brain

The Neuron ◽

10.1093/med/9780199773893.003.0001 ◽

2015 ◽

pp. 3-22

Author(s):

Irwin B. Levitan ◽

Leonard K. Kaczmarek

Keyword(s):

Nervous System ◽

Molecular Biology ◽

Intercellular Communication ◽

Information Transfer ◽

System Function ◽

Structural Elements ◽

Nervous System Function ◽

Specialized Structure ◽

Transfer Of Information ◽

Neurons are the cells of the brain responsible for intracellular and intercellular information transfer, or signaling; they are asymmetrical cells with morphologically and functionally distinct regions that specialize them for signaling. This chapter focuses on the unique structural elements characteristic of neurons throughout the animal kingdom. These include the dendrite, among whose functions is the receipt of information from other neurons. The axon, in contrast, is specialized for the intracellular transfer of information over long distances. The chapter concludes with a discussion of the synapse, the highly specialized structure that mediates the transfer of information from one neuron to another. It is this intracellular and intercellular communication that is the essence of nervous system function, and that makes the brain so complex and difficult to study and yet at the same time so fascinating for students of cell and molecular biology.