Evidence for axonal ‘decision regions’ in the axolotl peripheral nervous system

Development ◽  
1988 ◽  
Vol 102 (4) ◽  
pp. 823-836
Author(s):  
S. Wilson ◽  
N. Holder
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Spatial Organization ◽  
Retrograde Transport ◽  
Branch Points ◽  
Spinal Nerves ◽  
Lateral Motor Column ◽  
Decision Region ◽  
Muscle Nerve ◽  
Axial Musculature

Horseradish peroxidase (HRP) was employed to analyse the spatial organization of axons within nerves of the axolotl peripheral nervous system. HRP applications to the lateral motor column, spinal nerves and muscle nerve branches were examined after orthograde or retrograde transport. Axons change relative positions at particular limb regions, notably at the limb plexi, but also at branch points at other limb levels. Such areas of axon reorganization (termed ‘decision regions’ in line with Tosney & Landmesser (1985) J. Neurosci. 5, 2345) are interspersed by lengths of nerve in which axons run parallel to one another. A decision region is also described which involves only axons destined for axial musculature. The detailed anatomy of axon groups is discussed in terms of the likely mechanisms responsible for its formation during development. We conclude that, despite considerable variation in nerve pattern not seen in higher vertebrates, neuromuscular specificity in the axolotl limb is established largely by local pathway cues guiding axons to their appropriate targets.

scholarly journals The Number of Alphaherpesvirus Particles Infecting Axons and the Axonal Protein Repertoire Determines the Outcome of Neuronal Infection

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Orkide O. Koyuncu ◽  
Ren Song ◽  
Todd M. Greco ◽  
Ileana M. Cristea ◽  
Lynn W. Enquist
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Viral Entry ◽  
Retrograde Transport ◽  
Productive Infection ◽  
Long Distance ◽  
Viral Genomes ◽  
Neuronal Nuclei ◽  
Viral Particles ◽  
The Impact

ABSTRACTInfection by alphaherpesviruses invariably results in invasion of the peripheral nervous system (PNS) and establishment of either a latent or productive infection. Infection begins with long-distance retrograde transport of viral capsids and tegument proteins in axons toward the neuronal nuclei. Initial steps of axonal entry, retrograde transport, and replication in neuronal nuclei are poorly understood. To better understand how the mode of infection in the PNS is determined, we utilized a compartmented neuron culturing system where distal axons of PNS neurons are physically separated from cell bodies. We infected isolated axons with fluorescent-protein-tagged pseudorabies virus (PRV) particles and monitored viral entry and transport in axons and replication in cell bodies during low and high multiplicities of infection (MOIs of 0.01 to 100). We found a threshold for efficient retrograde transport in axons between MOIs of 1 and 10 and a threshold for productive infection in the neuronal cell bodies between MOIs of 1 and 0.1. Below an MOI of 0.1, the viral genomes that moved to neuronal nuclei were silenced. These genomes can be reactivated after superinfection by a nonreplicating virus, but not by a replicating virus. We further showed that viral particles at high-MOI infections compete for axonal proteins and that this competition determines the number of viral particles reaching the nuclei. Using mass spectrometry, we identified axonal proteins that are differentially regulated by PRV infection. Our results demonstrate the impact of the multiplicity of infection and the axonal milieu on the establishment of neuronal infection initiated from axons.IMPORTANCEAlphaherpesvirus genomes may remain silent in peripheral nervous system (PNS) neurons for the lives of their hosts. These genomes occasionally reactivate to produce infectious virus that can reinfect peripheral tissues and spread to other hosts. Here, we use a neuronal culture system to investigate the outcome of axonal infection using different numbers of viral particles and coinfection assays. We found that the dynamics of viral entry, transport, and replication change dramatically depending on the number of virus particles that infect axons. We demonstrate that viral genomes are silenced when the infecting particle number is low and that these genomes can be reactivated by superinfection with UV-inactivated virus, but not with replicating virus. We further show that viral invasion rapidly changes the profiles of axonal proteins and that some of these axonal proteins are rate limiting for efficient infection. Our study provides new insights into the establishment of silent versus productive alphaherpesvirus infections in the PNS.

Pathway selection by chick lumbosacral motoneurons during normal development

1981 ◽  
Vol 214 (1194) ◽  
pp. 1-18 ◽  
Keyword(s):  
Cell Death ◽  
Early Stage ◽  
Spinal Nerves ◽  
Functional Connections ◽  
Hindlimb Muscles ◽  
Lateral Motor Column ◽  
Normal Period ◽  
Axon Retraction ◽  
Muscle Nerve ◽  
Specific Muscle

Pathways taken by motoneuron axons from the lumbosacral lateral motor column to individual hindlimb muscles have been characterized throughout the normal period of outgrowth and the establishment of specific functional connections in the chick embryo. Axon pathways from individual cord segments were identified after injections of horseradish peroxidase (HRP) directly into the cord. Labelled motoneuron axons were then traced through the plexus and major nerve trunks to termi­nation sites within the limb. At stages 23-24 labelled axons within spinal nerves have just reached the base of the limb and have begun to converge and form the crural and the ischiadic plexus. Even at this early stage, before periods of muscle cleavage, motoneuron cell death and muscle nerve formation, axons show no evidence of widespread random distribution within the limb. Rather, they generally maintain their anterior-posterior position as far as the base of the limb. At stages 27-30, although axons to individual muscles were found to course in discrete tracts within the plexus and nerve trunks they also changed their topographical position with respect to other axons. Axon pathways to single muscles were characterized by tracing retrogradely labelled axons back to the cord after injections of HRP into specific muscle nerves. Axons destined for a single muscle are intermingled with other axons in the spinal nerves and proximal plexus but by the distal plexus have converged to form a discrete tract which then diverges as an individual muscle nerve at more distal levels. These observations exclude models for the establishment of specific connections in which there is widespread testing of the environment with removal of projection errors by cell death and/or axon retraction. They also exclude models that require axons to maintain their topographical position with respect to each other throughout their course.

Imaging Techniques Combined With Enzyme-Based Procedures That Facilitate the Simultaneous Imaging of Nerves, Neurons, Cartilage And Bones During Development In Gambusia

1999 ◽  
Vol 5 (S2) ◽  
pp. 1074-1075
Author(s):  
E. Rosa-Molinar
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Imaging Techniques ◽  
Retrograde Transport ◽  
Nerve Fibers ◽  
Staining Procedure ◽  
Alizarin Red ◽  
Persistent Problem ◽  
Simultaneous Visualization ◽  
And Cartilage

A persistent problem in elucidating the anatomy of the peripheral nervous system has been an inability to stain both myelinated and unmyelinated nerve fibers. To overcome this problem, our laboratory developed two workmg protocols for reliably and differentially labeling and staining the peripheral nervous system and combined them with an enzyme clearing and staining procedure for the simultaneous visualization of bone and cartilage.One protocol uses anti-acetylated α-tubulin immunohistochemistry to follow the course, peripheral branching, and origin of the ventral spinal nerve innervating the axial musculature and a second uses anterograde and retrograde transport of selectively applied 3000 molecular weight (MW) biotin dextran amines and/or biocytin to identify specific afferent and efferent projections and their cell bodies. Both procedures can be combined with an enzyme clearing and staining procedure for the simultaneous visualization of bone (alizarin red S) and cartilage (alcian blue) in whole-mount preparations.

Glucuronyl 3-sulfate occurs exclusively on distal unmyelinated terminals of selected sensory neurons in the peripheral nervous system

1995 ◽  
Vol 53 ◽  
pp. 958-959
Author(s):  
S.S. Spicer ◽  
B.A. Schulte
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Peripheral Nervous System ◽  
Sensory Neurons ◽  
Sensory Nerves ◽  
Tissue Antigens ◽  
The Central Nervous System ◽  
The Brain ◽  
Leu 7

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.

Questions and Answers

2000 ◽  
Vol 5 (2) ◽  
pp. 3-3
Author(s):  
Christopher R. Brigham ◽  
James B. Talmage
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Spinal Nerve ◽  
Sensory Loss ◽  
Residual Symptoms ◽  
Additional Information ◽  
Questions And Answers ◽  
Motor Nerves ◽  
Symptoms And Signs ◽  
Limited Motion

Abstract Lesions of the peripheral nervous system (PNS), whether due to injury or illness, commonly result in residual symptoms and signs and, hence, permanent impairment. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) describes procedures for rating upper extremity neural deficits in Chapter 3, The Musculoskeletal System, section 3.1k; Chapter 4, The Nervous System, section 4.4 provides additional information and an example. The AMA Guides also divides PNS deficits into sensory and motor and includes pain within the former. The impairment estimates take into account typical manifestations such as limited motion, atrophy, and reflex, trophic, and vasomotor deficits. Lesions of the peripheral nervous system may result in diminished sensation (anesthesia or hypesthesia), abnormal sensation (dysesthesia or paresthesia), or increased sensation (hyperesthesia). Lesions of motor nerves can result in weakness or paralysis of the muscles innervated. Spinal nerve deficits are identified by sensory loss or pain in the dermatome or weakness in the myotome supplied. The steps in estimating brachial plexus impairment are similar to those for spinal and peripheral nerves. Evaluators should take care not to rate the same impairment twice, eg, rating weakness resulting from a peripheral nerve injury and the joss of joint motion due to that weakness.

Chronic neonatal mild stress induces long lasting alterations on peripheral nervous system programming in mice

2004 ◽  
Author(s):  
G. Galietta ◽  
A. Capasso ◽  
A. Fortuna ◽  
F. Fabi ◽  
P. Del Basso ◽  
...  
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Mild Stress ◽  
System Programming
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