Nerve and muscle

Higher animals have four basic tissue types: epithelial tissue, connective tissue, nervous tissue, and muscle. Of these, nerve and muscle are grouped together as ‘excitable cells’ because the cell membrane has the ability to vary membrane ion conductance and membrane voltage so as to transmit meaningful signals within and between cells. Within excitable cells information is transmitted using either an amplitude-modulated (AM) code using slow, electrotonic potentials, or a frequency-modulated (FM) code when signalling is by action potentials. Much of the signalling between excitable cells occurs at chemical synapses where a chemical neurotransmitter is released from presynaptic cells and then interacts with postsynaptic membrane receptors. Clinical symptoms can arise when the release of chemical neurotransmitters is disturbed, or when availability of postsynaptic receptors is altered. Thus, a reduction in dopamine release from basal ganglia substantia nigra cells is found in Parkinson’s disease, while myasthenia gravis results from loss of nicotinic acetylcholine receptors at the neuromuscular junction of skeletal muscle. Sometimes transmission from cell to cell is not by chemical neurotransmitter but by electrical synapses, where gap-junctions provide direct electrical connectivity. Transmission between cardiac muscle cells occurs in this way. Some cardiac arrhythmias, such as Wolff –Parkinson–White syndrome, are a consequence of an abnormal path of electrical conduction between cardiac muscle fibres. Sensory cells on and within the body pass information via afferent pathways from the peripheral nervous system into the central nervous system (CNS). CNS processes and sensory information are integrated to produce outputs from the CNS. These outputs pass by various efferent routes to the effector organs: skeletal muscle, cardiac muscle, smooth muscle, and glands. It is through these effectors that the CNS is able to exert control over the body and to interact with the environment. Alterations of function anywhere in the afferent, integrative, or efferent aspects of the system, as well as defects in the effectors themselves, are likely to lead to significant clinical symptoms and signs. The efferent outflow from the CNS has two major components. One, the somatic nervous system, innervates only skeletal muscle. The other is the autonomic nervous system (ANS), which innervates cardiac muscle, smooth muscle, and the glands of the viscera and skin.

2019 ◽  
Vol 25 (26) ◽  
pp. 2892-2905 ◽  
Author(s):  
Sumit Jamwal ◽  
Ashish Mittal ◽  
Puneet Kumar ◽  
Dana M. Alhayani ◽  
Amal Al-Aboudi

Adenosine is a naturally occurring nucleoside and an essential component of the energy production and utilization systems of the body. Adenosine is formed by the degradation of adenosine-triphosphate (ATP) during energy-consuming processes. Adenosine regulates numerous physiological processes through activation of four subtypes of G-protein coupled membrane receptors viz. A1, A2A, A2B and A3. Its physiological importance depends on the affinity of these receptors and the extracellular concentrations reached. ATP acts as a neurotransmitter in both peripheral and central nervous systems. In the peripheral nervous system, ATP is involved in chemical transmission in sensory and autonomic ganglia, whereas in central nervous system, ATP, released from synaptic terminals, induces fast excitatory postsynaptic currents. ATP provides the energetics for all muscle movements, heart beats, nerve signals and chemical reactions inside the body. Adenosine has been traditionally considered an inhibitor of neuronal activity and a regulator of cerebral blood flow. Since adenosine is neuroprotective against excitotoxic and metabolic dysfunctions observed in neurological and ocular diseases, the search for adenosinerelated drugs regulating adenosine transporters and receptors can be important for advancement of therapeutic strategies against these diseases. This review will summarize the therapeutic potential and recent SAR and pharmacology of adenosine and its receptor agonists and antagonists.


2020 ◽  
Vol 26 (4) ◽  
pp. 214-218
Author(s):  
M. Lippert-Grüner ◽  
B. Bakaláø ◽  
R. Zajíèek ◽  
F. Duška

Zusammenfassung Die Optimierung der motorischen Leistung und die Einbindung und Vernetzung bisher nicht verwendeter motorischer Einheiten sowie die vermehrte Ausschüttung neurotropher Faktoren sind zentrale Mechanismen der Vibrationswirkung, die therapeutisch auf einzelne Körperteile oder den gesamten Körper angewendet werden können. Eine Möglichkeit, die Frühmobilisation bei kritisch kranken Patienten effektiver zu gestalten und immobilitätsbedingten Veränderungen vorzubeugen, könnte die Verwendung des Vibramoov™-Systems sein. Gezielt programmierte Vibrationssequenzen stimulieren hier das Nervensystem mit sensorischen Informationen, die die Empfindung einer Bewegung nachahmen (z. B. des Gehens) und somit Regenerations- und Reor-ganisationsprozesse im zentralen Nervensystem unterstützen können. Von Bedeutung ist dieser Therapieansatz vor allem bei Patienten, bei denen aufgrund ihres Zustandes konventionelle Maßnahmen nicht oder nur eingeschränkt durchgeführt werden können. Da bisher keine Erfah-rungen zur Anwendung bei intensivpflichtigen Patienten verfügbar sind, wurde eine Pilotstudie durchgeführt mit der Fragestellung, ob diese Therapieform sicher ist und im normalen Betrieb auf der Intensivstation verwendet werden kann. Die Ergebnisse der Pilotstudie mit fünf Patienten zei-gen, dass die Anwendung von Vibramoov™ zu keiner wesentlichen Veränderung kardiopulmo-naler Parameter im Sinne einer Non-Toleranz führte und im klinischen Setting gut umsetzbar war. Schlüsselwörter: Frührehabilitation, Imagination von Bewegung, Intensivstation, Vibramoov™ Imagination of movement through vibrational stimuli – a new approach to early mobilization in intensive care units? A pilot study Abstract The optimization of motor performance and the integration and networking of previously unused motor units, as well as the increased release of neurotrophic factors, are central mechanisms related to the vibration effect that can be applied therapeutically to individual parts of the body or to the entire body. One way to make early mobilization more effective in critically ill patients and to prevent changes due to immobility could be rehabilitation with functional proprioceptive stimulation, also known as “illusory movement”. Specifically programmed vibration sequences stimulate the nervous system with sensory information that mimics the sensation of movement (e. g., walking) and can thus support regeneration and reorganization processes in the central nervous system. This therapeutic approach is particularly important for patients who, due to their condition, cannot – or only to a limited extent – carry out conventional measures. Since no experience has so far been available for use in intensive care patients, we carried out a pilot study to answer the question of whether this form of therapy can be used safely and in normal operations in the intensive care unit. The results of the pilot study with 5 patients showed that the use of Vibramoov™ did not lead to any significant change in cardiopulmonary parameters in terms of non-tolerance and was easy to implement in a clinical setting. Keywords: early rehabilitation, illusory movements, ICU, functional proprio-ceptive stimulation


2001 ◽  
Vol 125 (2) ◽  
pp. 264-266
Author(s):  
Satish Krishnamurthy ◽  
Stephen Kent Powers ◽  
Javad Towfighi

Abstract Primitive neuroectodermal tumors (PNETs) of the central nervous system are uncommon embryonal neoplasms, rarely occurring in adults. Differentiation into specific mesenchymal tissues, such as cartilage, bone, skeletal muscle, smooth muscle, or adipose tissue, is rare. We report a case of a 51-year-old woman with a PNET of cerebrum that showed extensive mature adipose tissue differentiation. This is the second case, to our knowledge, of PNET of cerebrum with adipose tissue elements that has been described.


Author(s):  
T.C. Steven Keller ◽  
Christophe Lechauve ◽  
Alexander S Keller ◽  
Steven Brooks ◽  
Mitchell J Weiss ◽  
...  

Globin proteins exist in every cell type of the vasculature, from erythrocytes to endothelial cells, vascular smooth muscle cells, and peripheral nerve cells. Many globin subtypes are also expressed in muscle tissues (including cardiac and skeletal muscle), in other organ-specific cell types, and in cells of the central nervous system. The ability of each of these globins to interact with molecular oxygen (O2) and nitric oxide (NO) is preserved across these contexts. Endothelial α-globin is an example of extra-erythrocytic globin expression. Other globins, including myoglobin, cytoglobin, and neuroglobin are observed in other vascular tissues. Myoglobin is observed primarily in skeletal muscle and smooth muscle cells surrounding the aorta or other large arteries. Cytoglobin is found in vascular smooth muscle but can also be expressed in non-vascular cell types, especially in oxidative stress conditions after ischemic insult. Neuroglobin was first observed in neuronal cells, and its expression appears to be restricted mainly to the central and peripheral nervous systems. Brain and central nervous system neurons expressing neuroglobin are positioned close to many arteries within the brain parenchyma and can control smooth muscle contraction and, thus, tissue perfusion and vascular reactivity. Overall, reactions between NO and globin heme-iron contribute to vascular homeostasis by regulating vasodilatory NO signals and scaveging reactive species in cells of the mammalian vascular system. Here, we discuss how globin proteins affect vascular physiology with a focus on NO biology, and offer perspectives for future study of these functions.


Bioprinting ◽  
2021 ◽  
pp. 98-118
Author(s):  
Kenneth Douglas

Abstract: This chapter recounts bioprinting studies of skin, bone, skeletal muscle, and neuromuscular junctions. The chapter begins with a study of bioprinted skin designed to enable the creation of skin with a uniform pigmentation. The chapter relates two very different approaches to bioprinted bone: a synthetic bone called hyperelastic bone and a strategy that prints cartilage precursors to bone and then induces the conversion of the cartilage to bone by judicious choice of bioinks. Muscles move bone, and the chapter discusses an investigation of bioprinted skeletal muscle. Finally, the chapter considers an attempt to bioprint a neuromuscular junction, a synapse—a minute gap—of about 20 billionths of a meter between a motor neuron and the cell membrane of a skeletal muscle cell. A motor neuron is a nerve in the central nervous system that sends signals to the muscles of the body.


1959 ◽  
Vol 196 (3) ◽  
pp. 512-516 ◽  
Author(s):  
Adam Anthony ◽  
Eugene Ackerman ◽  
G. K. Strother

Analyses were made of myoglobin content of rat skeletal and cardiac muscle following continuous exposure to simulated altitudes of 18,000 feet for a 2–10-week period. About five dozen rats were used. Acclimatization was associated with an increase in the myoglobin concentration of thigh, diaphragm, gastrocnemius and heart muscles. Total myoglobin content, however, increased during acclimatization in cardiac muscle but not in the three skeletal muscles. This finding together with the body weight changes and muscle weight changes suggested that the increases in myoglobin concentration of skeletal muscle may be merely a reflection of a decreased water content of muscles.


1991 ◽  
Vol 115 (2) ◽  
pp. 411-421 ◽  
Author(s):  
T J Byers ◽  
L M Kunkel ◽  
S C Watkins

We use a highly specific and sensitive antibody to further characterize the distribution of dystrophin in skeletal, cardiac, and smooth muscle. No evidence for localization other than at the cell surface is apparent in skeletal muscle and no 427-kD dystrophin labeling was detected in sciatic nerve. An elevated concentration of dystrophin appears at the myotendinous junction and the neuromuscular junction, labeling in the latter being more intense specifically in the troughs of the synaptic folds. In cardiac muscle the distribution of dystrophin is limited to the surface plasma membrane but is notably absent from the membrane that overlays adherens junctions of the intercalated disks. In smooth muscle, the plasma membrane labeling is considerably less abundant than in cardiac or skeletal muscle and is found in areas of membrane underlain by membranous vesicles. As in cardiac muscle, smooth muscle dystrophin seems to be excluded from membrane above densities that mark adherens junctions. Dystrophin appears as a doublet on Western blots of skeletal and cardiac muscle, and as a single band of lower abundance in smooth muscle that corresponds most closely in molecular weight to the upper band of the striated muscle doublet. The lower band of the doublet in striated muscle appears to lack a portion of the carboxyl terminus and may represent a dystrophin isoform. Isoform differences and the presence of dystrophin on different specialized membrane surfaces imply multiple functional roles for the dystrophin protein.


1996 ◽  
Vol 270 (2) ◽  
pp. R462-R468 ◽  
Author(s):  
L. M. Larkin ◽  
J. B. Halter ◽  
M. A. Supiano

In this study, we tested the hypothesis that, in the male Fischer 344 x Brown Norway (F344xBN) rat, aging would be associated with an increase in sympathetic nervous system activity and a decrease in skeletal muscle beta-adrenergic-receptor (beta-AR) density and function. Radioligand-binding studies using [125I] iodocyanopindolol were done to evaluate beta-AR density (Bmax) and antagonist-binding affinity in gastrocnemius and cardiac muscle from 6-, 18-, and 28-mo-old male F344xBN rats. beta-AR function was measured as adenylyl cyclase (AC) activity stimulated by the beta-AR agonist isoproterenol (Iso, 10(-4) M). Basal arterial plasma norepinephrine (pNE) concentrations were higher in the 28-than in the 6- and 18-mo-old rats. Bmax was greatest and Iso-stimulated AC activity was unchanged in gastrocnemius muscle of the 28-mo-old age group. In contrast, there was an age-associated decrease in Bmax and Iso-stimulated AC activity in cardiac muscle. In conclusion, there was an age-associated increase in pNE concentrations in male F344xBN rats, suggesting an increase in sympathetic nervous system activity. In addition, there was an age-associated increase in skeletal muscle beta-AR density, whereas in skeletal muscle beta-AR-stimulated AC activity remained unchanged with age.


1983 ◽  
Vol 97 (3) ◽  
pp. 887-901 ◽  
Author(s):  
G Wiche ◽  
R Krepler ◽  
U Artlieb ◽  
R Pytela ◽  
H Denk

Various tissues from rat were examined for the occurrence and cellular localization of plectin, a 300,000-dalton polypeptide component present in intermediate filament-enriched cytoskeletons prepared from cultured cells by treatment with nonionic detergent and high salt solution. The extraction of liver, heart, skeletal muscle, tongue, and urinary bladder with 1% Triton/0.6 M KCl yielded insoluble cell residues that contained polypeptides of Mr 300,000 in variable amounts. These high Mr polypeptide species and a few bands of slightly lower Mr (most likely proteolytic breakdown products) were shown to react with antibodies to rat glioma C6 cell plectin using immunoautoradiography and/or immunoprecipitation. By indirect immunofluorescence microscopy using frozen sections (4 micron) of stomach, kidney, small intestine, liver, uterus, urinary bladder, and heart, antigens reacting with antibodies to plectin were found in fibroblast, endothelial, smooth, skeletal, and cardiac muscle, nerve, and epithelial cells of various types. Depending on the cell type, staining was observed either throughout the cytoplasm, or primarily at the periphery of cells, or in both locations. In hepatocytes, besides granular staining at the cell periphery, conspicuous staining of junctions sealing bile canaliculi was seen. In cardiac muscle strong staining was seen at intercalated disks and, as in skeletal muscle, at Z-lines. In cross sections through smooth muscle, most strikingly of urinary bladder, antibodies to plectin specifically decorated regularly spaced, spot-like structures at the cell periphery. By immunoelectron microscopy using the peroxidase technique, antiplectin-reactive material was found along cell junctions of hepatocytes and was particularly enriched at desmosomal plaques and structures associated with their cytoplasmic surfaces. A specific immunoreaction with desmosomes was also evident in sections through tongue. In cardiac muscle, besides Z-lines, intercalated disks were reactive along almost their entire surface, suggesting that plectin was associated with the fascia adherens, desmosomes, and probably gap junctions. In smooth muscle cells, regularly spaced lateral densities probably representing myofilament attachment sites were immunoreactive with plectin antibodies. The results show that plectin is of widespread occurrence with regard to tissues and cell types. Furthermore, immunolocalization by light and electron microscopy at junctional sites of various cell types and at attachment sites of cytoplasmic filaments in epithelial and muscle cells suggests that plectin possibly plays a universal role in the formation of cell junctions and the anchorage of cytoplasmic filaments.


1974 ◽  
Vol 141 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Peter Cummins ◽  
S. Victor Perry

1. On electrophoresis in dissociating conditions the tropomyosins isolated from skeletal muscles of mammalian, avian and amphibian species migrated as two components. These were comparable with the α and β subunits of tropomyosin present in rabbit skeletal muscle. 2. The α and β components of all skeletal-muscle tropomyosins contained 1 and 2 residues of cysteine per 34000g respectively. 3. The ratio of the amounts of α and β subunit present in skeletal muscle tropomyosins was characteristic for the muscle type. Muscle consisting of slow red fibres contained a greater proportion of β-tropomyosin than muscles consisting predominantly of white fast fibres. 4. Mammalian and avian cardiac muscle tropomyosins consisted of α-tropomyosin only. 5. Mammalian and avian smooth-muscle tropomyosins differed both chemically and immunologically from striated-muscle tropomyosins. 6. Antibody raised against rabbit skeletal α-tropomyosin was species non-specific, reacting with all other striated muscle α-tropomyosin subunits tested. 7. Antibody raised against rabbit skeletal β-tropomyosin subunit was species-specific.


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