Lysosomal activity at nodes of Ranvier in dorsal column and dorsal root axons of the cat after injection of horseradish peroxidase in the dorsal column nuclei

Gatzinsky, Kliment; Berthold, C.‐H.; Fabricius, C.; Mellström, A.

doi:10.1016/0006-8993(91)91690-3

Cited by 11 publications

(8 citation statements)

References 38 publications

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“…In none of these nodes did the AcPase activity approach the intensity of the strongest AcPase-positive nodeparanode regions in alpha-motor axons of adult cats. Despite a n extensive retrograde HRP-labelling of both dorsal column and dorsal root axons after injection of the tracer in the dorsal column nuclei, there were no changes in the Occurrence or distribution of lysosomes in these axons, as compared to axons of cats not exposed to HRP (Gatzinsky et al, 1991b).…”

Section: Table I Light Microscopic Quantitative Analysis Of the Occmentioning

confidence: 75%

Node-paranode regions as local degradative centres in alpha-motor axons

Gatzinsky

1996

Microsc. Res. Tech.

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Lysosomes play an important role for the maintenance of a normal internal milieu in the cell. In neurons lysosomes are abundant in the perikaryon and dendrites, but have been observed to a much lesser degree in the axon. A general opinion has therefore formed among biologists interested in the nervous system that axonal material destined for degradation has to be transported to the neuronal perikaryon. The lysosomal occurrence and distribution at the level of the axon have, however, not been investigated systematically. This review summarizes recent morphological data based on light, fluorescence, and electron microscopic observations in peripheral nerve fibres of cats and rats providing evidence that node‐paranode regions mainly along the peripheral parts of alpha motor axons, where the axon cross‐section area decreases to 10–25% of internodal values, can control the passage and participate in a lysosome‐mediated degradation of axonally transported materials directed towards the neuronal perikaryon. An important role is played by the paranodal axon‐Schwann cell networks, which are lysosome‐rich entities whereby the Schwann cells can sequester material from the axoplasm of large myelinated peripheral nerve fibres. The networks also seem to serve as depots for axonal waste products. The degradative ability of node‐paranode regions in alpha‐motor axons could be of some significance for the protection of the motor neuron perikarya from being flooded with and perhaps injured by indigestible materials as well as potentially deleterious, exogenous substances imbibed by the axon terminals in the muscle. A similar degradative capacity may not be needed in nerve fibres with synaptic terminals in the CNS where the local environment is regulated by the blood‐brain barrier. © 1996 Wiley‐Liss, Inc.

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Section: Table I Light Microscopic Quantitative Analysis Of the Occmentioning

confidence: 75%

Node-paranode regions as local degradative centres in alpha-motor axons

Gatzinsky

1996

Microsc. Res. Tech.

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“…Taken in concert with our previous observations of a high concentration of lysosomes in many node-paranodes along the ventral root parts of alpha-motor axons, where a degradation of axonally transported substances can be initiated before arrival at the perikaryon (Gatzinsky and Berthold, 1990;Gatzinsky et al, 1988Gatzinsky et al, , 1991a; see also Overly et al, 1995;Overly and Hollenbeck, 1996), the ability of ASNs to segregate organelles containing extraneous material and effete axoplasmic constituents could give some shield to the motor neuron perikaryon from being pervaded by potentially harmful molecules transported from the periphery to the CNS, as well as being crammed with degenerating organelles and products resulting from a local degradation in the axon. This speculation is interesting in light of earlier findings that ASNs are less elaborate in node-paranode regions of dorsal root axons, the synaptic terminals of which reside in the CNS (Gatzinsky et al, 1991b), and that these axons also contain considerably fewer lysosomes than alpha-motor axons (Gatzinsky et al, 1988(Gatzinsky et al, , 1991c.…”

Section: Discussionmentioning

confidence: 92%

Removal of retrogradely transported material from rat lumbosacral alpha-motor axons by paranodal axon-schwann cell networks

1997

Glia

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“…In this study we have artificially applied an "inert" tracer, HRP, thus bypassing the blood-brain barrier and thus surpassed the presumed protection of the CNS terminals. The absence of prolonged accumulations of retrogradely transported HRP in the CNS pnp-regions and the previously observed absence of aggregations of lysosomes in the CNS axons (Gatzinsky et al 1991b) could indicate that potentially toxic substances that have passed the blood-brain barrier and are taken up by the axon terminals can be distributed more or less unhindered in the CNS by retrograde transport.…”

Section: Discussionmentioning

confidence: 93%

Horseradish peroxidase in axons of the dorsal funiculi of the cat: distribution after an injection of the enzyme into the dorsal column nuclei

Fabricius

Berthold

Gatzinsky

1995

Cell and Tissue Research

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Horseradish peroxidase (HRP) was injected into the left dorsal column nuclei of adult cats. Large dorsal funiculi axons of the C3, C5, C8 and L7 segments were searched for HRP-activity after 12, 24, 36 and 48h using light and electron microscopy. Accumulations of intra-axonal HRP-positive bodies occurred at nodes of Ranvier in the C3-C8 segments at 12, 24 and 36h and in the L7 segments at 24, 36, and 48h. The accumulations of HRP in three spatio-temporally different consecutive patterns, noted earlier at nodes of Ranvier in the peripheral nervous system (PNS) portion of feline alpha motor axons for more than 70h after an intramuscular injection of the enzyme, were not observed in the present material. We suggest that the differences in the modes in which large PNS and CNS axons interact with retrogradely transported HRP are due to differences in the organization of the respective nodal regions. We also emphasize that endocytosis via axon terminals in the CNS normally represents uptake of material from an extracellular space which is controlled and protected by the blood-brain barrier. This is in contrast to endocytosis via axon terminals in a muscle, which represents uptake of material from an extracellular space openly exposed to influx of different substances from the blood stream.

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Lysosomal activity at nodes of Ranvier in dorsal column and dorsal root axons of the cat after injection of horseradish peroxidase in the dorsal column nuclei

Cited by 11 publications

References 38 publications

Node-paranode regions as local degradative centres in alpha-motor axons

Node-paranode regions as local degradative centres in alpha-motor axons

Removal of retrogradely transported material from rat lumbosacral alpha-motor axons by paranodal axon-schwann cell networks

Horseradish peroxidase in axons of the dorsal funiculi of the cat: distribution after an injection of the enzyme into the dorsal column nuclei

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