Formation de novo and development of neuromuscular junctions in vitro

Development ◽  
1969 ◽  
Vol 21 (2) ◽  
pp. 369-382
Author(s):  
Giorgio Veneroni ◽  
Margaret R. Murray
Keyword(s):  
De Novo ◽  
Neuromuscular Junctions ◽  
Nerve Fibers ◽  
Sensory Pathways ◽  
Motor End Plate ◽  
The Central Nervous System ◽  
Motor Nerves ◽  
Nerve Muscle ◽  
Formation De Novo

The purpose of this study has been to examine, by means of isolation in vitro, the conditions under which neuromyal junctions develop. More than a hundred years ago Doyère (1840) observed in the water-bear Milnesium tardigradum that the nerve fibers terminate in characteristic eminences of muscle fibers. This observation, made on an arthropod, stimulated research into the connexion between muscle and nerve fiber, and resulted in abandonment of the older concept that motor nerves after having formed loops around the muscles return to the central nervous system as sensory pathways. Although investigations during the intervening century have identified and characterized morphologically the ‘motor end plate’ (as it was designated by Krause, 1863), and have revealed microscopic and fine-structural differences between types of motor endings, there is as yet no general agreement on the respective roles played by nerve, muscle and ambient influences in the development of the neuromuscular junction.

Barbiturates depress vagal motor pathway to ferret trachea at ganglia

1982 ◽  
Vol 53 (1) ◽  
pp. 253-257 ◽  
Author(s):  
B. E. Skoogh ◽  
M. J. Holtzman ◽  
J. R. Sheller ◽  
J. A. Nadel
Keyword(s):  
Neuromuscular Junction ◽  
Vagus Nerve ◽  
Muscle Tension ◽  
Postsynaptic Membrane ◽  
Nerve Fibers ◽  
Motor Pathway ◽  
Parasympathetic Ganglia ◽  
Before And After ◽  
Nerve Muscle

To determine which site in the vagal motor pathway to airway smooth muscle is most sensitive to depression by barbiturates, we recorded isometric muscle tension in vitro and stimulated the vagal motor pathway at four different sites before and after exposure to barbiturates. In isolated tracheal rings from ferrets, we stimulated muscarinic receptors in the neuromuscular junction by exogenous acetylcholine, postganglionic nerve fibers by electrical fluid stimulation, and the postsynaptic membrane in ganglia by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). We also developed a tracheal nerve-muscle preparation to stimulate preganglionic fibers in the vagus nerve electrically. Activation of ganglia by DMPP or by vagus nerve stimulation was depressed by barbiturates at 10-fold lower concentrations than those depressing the activation of postganglionic nerves or the neuromuscular junction. These findings suggest that the postsynaptic membrane in parasympathetic ganglia is the site in the vagal motor pathway most sensitive to depression by barbiturates.

scholarly journals Intranasal Borna Disease Virus (BoDV-1) Infection: Insights into Initial Steps and Potential Contagiosity

2019 ◽  
Vol 20 (6) ◽  
pp. 1318 ◽  
Author(s):  
Alexandra Kupke ◽  
Sabrina Becker ◽  
Konstantin Wewetzer ◽  
Barbara Ahlemeyer ◽  
Markus Eickmann ◽  
...  
Keyword(s):  
Viral Infections ◽  
Cell Types ◽  
Nerve Fibers ◽  
Olfactory Pathway ◽  
Adult Rats ◽  
The Central Nervous System ◽  
Receptor Neurons

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory pathway. However, (I) susceptible cell types that replicate the virus for successful spread, and (II) the role of olfactory ensheathing cells (OECs), remained unclear. To address this, we studied the intranasal infection of adult rats with BoDV-1 in vivo and in vitro, using olfactory mucosal (OM) cell cultures and the cultures of purified OECs. Strikingly, in vitro and in vivo, viral antigen and mRNA were present from four days post infection (dpi) onwards in the olfactory receptor neurons (ORNs), but also in all other cell types of the OM, and constantly in the OECs. In contrast, in vivo, BoDV-1 genomic RNA was only detectable in adult and juvenile ORNs, nerve fibers, and in OECs from 7 dpi on. In vitro, the rate of infection of OECs was significantly higher than that of the OM cells, pointing to a crucial role of OECs for infection via the olfactory pathway. Thus, this study provides important insights into the transmission of neurotropic viral infections with a zoonotic potential.

Vagal input enhances responsiveness of respiratory discharge to central changes in pH/CO2 in bullfrogs

1994 ◽  
Vol 77 (4) ◽  
pp. 2048-2051 ◽  
Author(s):  
R. Kinkead ◽  
W. G. Filmyer ◽  
G. S. Mitchell ◽  
W. K. Milsom
Keyword(s):  
Breathing Pattern ◽  
Intrinsic Property ◽  
Afferent Input ◽  
Motor Output ◽  
Burst Frequency ◽  
Central Chemosensitivity ◽  
Temporal Relationships ◽  
The Central Nervous System ◽  
Motor Nerves

This study investigated the interaction between vagal afferent input and central chemosensitivity in modulating the respiratory motor output of in vitro brain stem-spinal cord preparations from adult bullfrogs. With this preparation, the spatiotemporal distribution of respiratory-related motor output emulated that of intact bullfrogs; that is, the fictive breathing pattern was mostly episodic. Recordings from cranial motor nerves (V and X) showed that, without peripheral feedback, increasing the PCO2 of the mock cerebrospinal fluid (thereby reducing pH from 8.3 to 7.7) caused a modest increase in respiration-related burst frequency. When the pulmonary branch of a vagus nerve was stimulated phasically (2 V, 20 Hz, 0.2 ms) during each fictive breath to simulate afferent pulmonary stretch receptor feedback 1) the responsiveness of the preparation to the same changes in pH was augmented nearly threefold and 2) the breathing pattern remained episodic. It appears, therefore, that episodic breathing is an intrinsic property of the central nervous system in bullfrogs. It is concluded that there is a strong interaction between vagal feedback and central chemodetection in controlling the temporal relationships that characterize this episodic breathing pattern.

scholarly journals Characterization of More Selective Central Nervous System Nrf2-Activating Novel Vinyl Sulfoximine Compounds Compared to Dimethyl Fumarate

2020 ◽  
Vol 17 (3) ◽  
pp. 1142-1152 ◽  
Author(s):  
Karl E. Carlström ◽  
Praveen K. Chinthakindi ◽  
Belén Espinosa ◽  
Faiez Al Nimer ◽  
Elias S. J. Arnér ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
De Novo ◽  
Dimethyl Fumarate ◽  
The Novel ◽  
The Central Nervous System ◽  
Demyelinating Disorders ◽  
Target Effects

Abstract The Nrf2 transcription factor is a key regulator of redox reactions and considered the main target for the multiple sclerosis (MS) drug dimethyl fumarate (DMF). However, exploration of additional Nrf2-activating compounds is motivated, since DMF displays significant off-target effects and has a relatively poor penetrance to the central nervous system (CNS). We de novo synthesized eight vinyl sulfone and sulfoximine compounds (CH-1–CH-8) and evaluated their capacity to activate the transcription factors Nrf2, NFκB, and HIF1 in comparison with DMF using the pTRAF platform. The novel sulfoximine CH-3 was the most promising candidate and selected for further comparison in vivo and later an experimental model for traumatic brain injury (TBI). CH-3 and DMF displayed comparable capacity to activate Nrf2 and downstream transcripts in vitro, but with less off-target effects on HIF1 from CH-3. This was verified in cultured microglia and oligodendrocytes (OLs) and subsequently in vivo in rats. Following TBI, DMF lowered the number of leukocytes in blood and also decreased axonal degeneration. CH-3 preserved or increased the number of pre-myelinating OL. While both CH-3 and DMF activated Nrf2, CH-3 showed less off-target effects and displayed more selective OL associated effects. Further studies with Nrf2-acting compounds are promising candidates to explore potential myelin protective or regenerative effects in demyelinating disorders.

scholarly journals THE ULTRASTRUCTURE AND DISPOSITION OF VESICULATED NERVE PROCESSES IN SMOOTH MUSCLE

1963 ◽  
Vol 16 (2) ◽  
pp. 361-377 ◽  
Author(s):  
J. C. Thaemert
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Plasma Membranes ◽  
Neuromuscular Junctions ◽  
Muscle Cells ◽  
Nerve Fibers ◽  
Intercellular Spaces ◽  
Intimate Contact ◽  
Smooth Muscle Tissue ◽  
The Central Nervous System

The walls of the gastrointestinal tract and urinary bladder of rats were fixed in osmium tetroxide, embedded in methacrylate, and sectioned for electron microscopy. The examination of sections of smooth muscle tissue with the electron microscope reveals the presence of bundles of unmyelinated nerve fibers within the intercellular spaces. In addition, vesiculated nerve processes, bounded on their outer surfaces by delicate plasma membranes and typically containing varying quantities of synaptic vesicles and mitochondria, make intimate contact with the surface of smooth muscle cells. These nerve processes are similar in structure and disposition to nerve endings previously described in skeletal muscle, in the central nervous system, in peripheral ganglia, in receptors, and in glands. It is concluded that the relationships existing between vesiculated nerve processes and the surface of smooth muscle cells constitute neuromuscular junctions. Profiles of protrusions of smooth muscle cells are often seen protruding into the intercellular spaces. Here they occur singly or in groups, originating from one or more cells. Because of the plane of section the protrusions may sometimes appear as individual entities between the muscle cells. In such cases care must be exercised in their identification because they have characteristics similar to sectioned nerve processes which also occur in the intercellular spaces.

In vitro reinnervation of adult rat muscle fibres by foreign neurons and transformed chromaffin PC12 cells

1988 ◽  
Vol 234 (1274) ◽  
pp. 1-9 ◽  
Keyword(s):  
Pc12 Cells ◽  
Neuromuscular Junctions ◽  
Mean Amplitude ◽  
Muscle Fibres ◽  
Adult Rat ◽  
Rat Muscle ◽  
Pheochromocytoma Pc12 ◽  
Nerve Muscle ◽  
Miniature Endplate Potentials

Adult rat muscle fibres were dissociated by using collagenase and maintained in culture. One to nine days later, neurons obtained from stages 22–30 Xenopus laevis embryos, or neonatal spinal cord, or pheochromocytoma (PC12) cells treated with nerve growth factor were added. Subsequently, the co-cultures were maintained for up to eight days. Functional synapses were formed with variable efficiency: 12% in rat– Xenopus nerve–muscle co-cultures, 23% in rat–rat and 33% in PC12 co-cultures. Miniature endplate potentials(MEPPs) and currents (MEPCs) were recorded, at frequencies ranging from 0.01 to 0.9 Hz. Their mean amplitude was smaller than in normal mammalian muscles. The rise time and time-constant of decay of MEPCs was about seven to ten times longer than that found in the original muscle, resembling immature synapses. (+)-Tubocurarine abolished the MEPPs in the rat-PC12 neuromuscular junctions. It is concluded that dissociated adult rat muscle fibres retain their ability of being reinnervated, and can form functional synapses with foreign neurons and transformed chromaffin cells.

scholarly journals Guide Cells Support Muscle Regeneration and Affect Neuro-Muscular Junction Organization

2021 ◽  
Vol 22 (4) ◽  
pp. 1939
Author(s):  
Flavio L. Ronzoni ◽  
Nefele Giarratana ◽  
Stefania Crippa ◽  
Mattia Quattrocelli ◽  
Marco Cassano ◽  
...  
Keyword(s):  
Muscle Regeneration ◽  
Muscle Injury ◽  
De Novo ◽  
Neuromuscular Junctions ◽  
Myogenic Differentiation ◽  
Cell Types ◽  
Acute Injury ◽  
Complex Biological Process ◽  
Junction Formation

Muscular regeneration is a complex biological process that occurs during acute injury and chronic degeneration, implicating several cell types. One of the earliest events of muscle regeneration is the inflammatory response, followed by the activation and differentiation of muscle progenitor cells. However, the process of novel neuromuscular junction formation during muscle regeneration is still largely unexplored. Here, we identify by single-cell RNA sequencing and isolate a subset of vessel-associated cells able to improve myogenic differentiation. We termed them ‘guide’ cells because of their remarkable ability to improve myogenesis without fusing with the newly formed fibers. In vitro, these cells showed a marked mobility and ability to contact the forming myotubes. We found that these cells are characterized by CD44 and CD34 surface markers and the expression of Ng2 and Ncam2. In addition, in a murine model of acute muscle injury and regeneration, injection of guide cells correlated with increased numbers of newly formed neuromuscular junctions. Thus, we propose that guide cells modulate de novo generation of neuromuscular junctions in regenerating myofibers. Further studies are necessary to investigate the origin of those cells and the extent to which they are required for terminal specification of regenerating myofibers.

scholarly journals Synthetic Pinnatoxins A and G Reversibly Block Mouse Skeletal Neuromuscular Transmission In Vivo and In Vitro

Marine Drugs ◽  
2019 ◽  
Vol 17 (5) ◽  
pp. 306 ◽  
Author(s):  
Evelyne Benoit ◽  
Aurélie Couesnon ◽  
Jiri Lindovsky ◽  
Bogdan I. Iorga ◽  
Rómulo Aráoz ◽  
...  
Keyword(s):  
Neuromuscular Transmission ◽  
Neuromuscular Junctions ◽  
Direct Action ◽  
Compound Muscle Action Potential ◽  
Docking Studies ◽  
Dependent Manner ◽  
Muscle Type ◽  
Nerve Muscle

Pinnatoxins (PnTXs) A-H constitute an emerging family belonging to the cyclic imine group of phycotoxins. Interest has been focused on these fast-acting and highly-potent toxins because they are widely found in contaminated shellfish. Despite their highly complex molecular structure, PnTXs have been chemically synthetized and demonstrated to act on various nicotinic acetylcholine receptor (nAChR) subtypes. In the present work, PnTX-A, PnTX-G and analogue, obtained by chemical synthesis with a high degree of purity (>98%), have been studied in vivo and in vitro on adult mouse and isolated nerve-muscle preparations expressing the mature muscle-type (α1)2β1δε nAChR. The results show that PnTX-A and G acted on the neuromuscular system of anesthetized mice and blocked the compound muscle action potential (CMAP) in a dose- and time-dependent manner, using a minimally invasive electrophysiological method. The CMAP block produced by both toxins in vivo was reversible within 6–8 h. PnTX-A and G, applied to isolated extensor digitorum longus nerve-muscle preparations, blocked reversibly isometric twitches evoked by nerve stimulation. The action of PnTX-A was reversed by 3,4-diaminopyridine. Both toxins exerted no direct action on muscle fibers, as revealed by direct muscle stimulation. PnTX-A and G blocked synaptic transmission at mouse neuromuscular junctions and PnTX-A amino ketone analogue (containing an open form of the imine ring) had no effect on neuromuscular transmission. These results indicate the importance of the cyclic imine for interacting with the adult mammalian muscle-type nAChR. Modeling and docking studies revealed molecular determinants responsible for the interaction of PnTXs with the muscle-type nAChR.

scholarly journals DEVELOPMENT OF THE NEUROMUSCULAR JUNCTION

1972 ◽  
Vol 55 (1) ◽  
pp. 93-103 ◽  
Author(s):  
Thomas L. Lentz
Keyword(s):  
Schwann Cell ◽  
Cholinesterase Activity ◽  
Neuromuscular Junctions ◽  
Synaptic Cleft ◽  
Axon Terminals ◽  
End Plate ◽  
Motor End Plate ◽  
Motor End Plates

To determine the effects of nerve explants on the integrity of motor end plates in vitro, cholinesterase activity and structure of end plates were compared in newt muscle denervated in vivo, cultured in the absence of nerve explants, and cultured in the presence of sensory ganglia. In neuromuscular junctions denervated in vivo or in vitro, the synaptic vesicles become clumped and fragmented. A few intact vesicles escape into the synaptic cleft. Axon terminals degenerate until they are left as residual bodies within the Schwann cell cytoplasm. Junctional folds on the muscle surface are reduced in height and are no longer evident once traces of axoplasm within the Schwann cell disappear. End plate cholinesterase activity is reduced as junctional folds are lost. When muscle is cultured in the presence of a sensory ganglion, the terminal axoplasm degenerates in the same manner but junctional folds persist on the muscle surface. Moderately intense cholinesterase activity remains in association with the junctional folds, so that normal motor end plates are maintained in the absence of innervation. These results show that degenerative changes in the structure of the motor end plate and loss of cholinesterase activity occurring in organ culture as a result of denervation can be retarded by nerve explants that do not directly innervate the muscle.

Denervation, Reinnervation, and Regeneration of Skeletal Muscle

1981 ◽  
Vol 89 (2) ◽  
pp. 192-196 ◽  
Author(s):  
Bruce M. Carlson
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Junction ◽  
Functional Ability ◽  
De Novo ◽  
Neuromuscular Junctions ◽  
Original Structure ◽  
De Novo Synthesis ◽  
Regenerative Capacity ◽  
Neuromuscular Synapses ◽  
Motor End Plate

This paper reviews the responses of skeletal muscle tissue to denervation, with emphasis on the area of neuromuscular junction. In reinnervation, neuromuscular synapses are formed preferentially at the site of the old motor end plate, but the de novo synthesis of new neuromuscular junctions is possible. Skeletal muscle has a good regenerative capacity, and a regenerating muscle fiber can, essentially, return to original structure and functional ability.

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