Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Axonal Transport”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1992

Local modulation of neurofilament phosphorylation, axonal caliber, and slow axonal transport by myelinating Schwann cells.

Studies in Trembler and control mice demonstrated that myelinating Schwann cells exert a profound influence on axons. Extensive contacts between myelin and axons have been considered structural. However, demyelination decreases neurofilament phosphorylation, slow axonal transport, and axonal diameter, as well as significantly increasing neurofilament density. In control sciatic nerves with grafted Trembler nerve segments, these changes were spatially restricted: they were confined to axon segments without normal myelination. Adjacent regions of the same axons had normal diameters, neurofilament phosphorylation, cytoskeletal organization, and axonal transport rates. Close intercellular contacts between myelinating Schwann cells and axons modulate a kinase-phosphatase system acting on neurofilaments and possibly other substrates. Myelination by Schwann cells sculpts the axon-altering functional architecture, electrical properties, and neuronal morphologies.

Animals↗
PubMed2005

Quantitative analysis of the relationship between intra- axonal neurofilament compaction and impaired axonal transport following diffuse traumatic brain injury.

Traumatic axonal injury (TAI) following traumatic brain injury (TBI) contributes to morbidity and mortality. TAI involves intra-axonal changes assumed to progress to impaired axonal transport (IAT), disconnection, and axonal bulb formation. Immunocytochemical studies employing antibodies to amyloid precursor protein (APP), a marker of IAT and RMO14, a marker of neurofilament compaction (NFC), have shown that TAI involves both NFC and IAT, with the suggestion that NFC leads to IAT. Recently, new data has suggested that NFC may occur independently of IAT. The objective of this study was to determine quantitatively the precise relationship between NFC and IAT. Following TBI, rats were studied at 30 min, 3 h, and 24 h. Using single-label immunocytochemistry employing the antibodies RM014, APP, or a combined labeling strategy targeting APP/RMO14 in aggregate, the immunoreactive (IR) profiles were counted in the corticospinal tract (CSpT) and medial lemniscus (ML). In the CSpT, the number of axons demonstrating RMO14-IR approximated the number of axons showing APP-IR, with the APP-IR population showing a significant increase over 24 h (p < 0.05). The sum of both single-label counts equaled the aggregate APP/RMO14 numbers, demonstrating little relationship between NFC and IAT. In the ML, 75% of fibers demonstrated a separation of APP-IR and NFC-IR; however, 25% of the ML fibers showed co-localization of APP-IR and RMO14. The results of these studies indicate that, in the majority of damaged axons, NFC is not associated with IAT. Our findings argue for the use of multiple markers when evaluating the extent of TAI or the efficacy of therapies targeting the treatment of TAI.

Amyloid beta-Protein Precursor↗
PubMed1982

Effect of sodium- or chloride-deficient medium on fast axonal transport in frog spinal nerves.

Fast axonal transport of radiolabeled proteins was studied in vitro in desheathed spinal nerves from frog. The replacement of the NaCl of the medium by LiCl reduced by 58% the amount of radiolabeled proteins which accumulated at a ligature, but its replacement by choline chloride did not inhibit transport. The replacement of NaCl by sodium isethionate led to a 32% reduction in the quantity of protein-bound radioactivity at the ligature. The results suggest that Cl-ions are essential to maintain fast axonal transport, and that Na+ may also be important.

Animals↗
PubMedDate not supplied

Decreased axonal transport in rat nerve following acute and chronic ethanol exposure.

The axonal transport system, which supplies essential proteins and other cellular components to the distal portions of peripheral nerve axons, has been postulated to be the primary site of vulnerability inducing the peripheral neuropathies associated with neurotoxin exposure. Axonal transport was examined in normal rat dorsal root ganglia-sciatic nerve preparations incubated 28 hours in vitro in the presence of 79, 198 or 395 mg% ethanol. Exposure of the nerves to 395 mg% ethanol significantly reduced the accumulation of radiolabeled protein by 70%. Also, groups of rats were pair-fed an ethanol or isocaloric control diet for 9, 16 or 28 weeks. In vitro axonal transport was found to be unchanged in nerves of rats fed the ethanol diet for 9 weeks, but was significantly reduced 44% after 16 weeks and 47% after 28 weeks of ethanol feeding. These results suggest that interference with the axonal transport machinery by ethanol or perhaps acetaldehyde, its primary metabolite, may lead to the development of alcoholic peripheral neuropathy.

Alcoholism↗
PubMed1980

Fate of axonally transported taurine and proteins in the developing rabbit visual system following optic nerve section.

These experiments were performed to characterize the axonally transported taurine in the visual system of developing rabbits. [35S]Taurine, transported axonally after intravitreal injection, disappeared from the components of the visual system more rapidly after nerve section than it did with intact nerves. The decrease was most rapid in the youngest animals, and tended to be most pronounced in the elements nearest to the section (optic nerve, optic tract). 3H-labeled proteins present in the visual system changed less markedly than [35S]taurine after nerve section; only in the youngest rabbits was there a marked decrease. These results suggest that a greater proportion of the intraaxonal taurine is labile in young rabbits than in mature rabbits.

Aging↗
PubMedDate not supplied

Melanocortins and fast axonal transport in intact and regenerating sciatic nerve.

The effect of ACTH/MSH peptides on fast axonal transport along intact or regenerating sciatic nerve was examined following injection of tritiated leucine into the rat lumbar spinal cord. The rate of fast axonal transport was not significantly changed by treatment with ACTH/MSH(4-10), the ACTH(4-9) analog ORG 2766, hypophysectomy, or adrenalectomy. Fast axonal transport was unchanged in regenerating nerves and in regenerating, ACTH(4-10)-treated nerves. However, treatment with ORG 2766 in dosages of either 1 or 10 micrograms/kg/day IP for seven days significantly reduced (62% and 64%, respectively) the crest height of the fast axonal transport curve of intact sciatic nerve. The results suggest that the reported peptide-induced enhancement of nerve regeneration is not due to changes in the rate of fast axonal transport.

Adrenalectomy↗
PubMed2005

Retrograde axonal transport of JNK signaling molecules influence injury induced nuclear changes in p-c-Jun and ATF3 in adult rat sensory neurons.

In the present study, we investigated if the previously observed JNK-mediated activation of c-Jun and induction of ATF3 could be ascribed to axonal transport of JNK signaling components, or if axonal transport of the transcription factors themselves contributes to the nuclear changes in injured sensory neurons. We observed retrograde axonal transport of a number of JNK upstream kinases in ligated rat sciatic nerve. In these preparations, axonal transport of JNK/p-JNK, the JNK scaffolding protein JIP, and the transcription factors ATF3 and ATF2/p-ATF2 was also found. No or little retrograde transport of c-Jun and p-c-Jun was found, whereas an anterograde transport of Hsp27, a protein previously reported in the context of p-c-Jun and ATF3, was observed. In separate experiments, we found that in vitro inhibition of axonal transport or axonal inhibition of JNK reduced the number of p-c-Jun- and ATF3-positive neuronal nuclei. The results suggest that retrograde axonal transport of JNK signaling components contributes to the injury induced c-Jun phosphorylation and ATF3 induction.

Activating Transcription Factor 2↗
PubMed1980

Failure of unilateral carotid artery ligation to affect pressure-induced interruption of rapid axonal transport in primate optic nerves.

Previous experiments showed that optic nerve axonal transport can be blocked at the level of the lamina cribrosa by elevated intraocular pressure. In an effort to discover if this blockage might be secondary to pressure-induced ischemia, we studied the effect of unilateral common carotid artery ligation upont the pressure-induced interruption of axonal transport. In 13 owl monkeys (Aotus trivirgatus), the right common carotid artery was ligated within the anterior cervical triangle. Three days later, ophtalmodynomometry was performed on all experimental eyes. In nine of the 13 animals, this estimate of ophthalmic artery pressure was 10 to 20 mm Hg less in the right compared to the left eye. Optic nerve axonal transport was studied in right and left eyes during 5 hours of increased intraocular pressure (ocular pressure 35 mm Hg less than mean femoral artery blood pressure). No significant difference in the extent to which the transport mechanisms were interrupted could be demonstrated when comparing right and left eyes of the experimental animals. These observations fail to support a vascular mechanism for this pressure-induced interruption of axonal transport.

Animals↗
PubMed1981

Clathrin is axonally transported as part of slow component b: the microfilament complex.

During axonal transport, membranes travel down axons at a rapid rate, whereas the cytoskeletal elements travel in either of two slow components, SCa (with tubulin and neurofilament protein) and SCb (with actin). Clathrin, the highly ordered, structural coat protein of coated vesicles, has recently been shown to be able to interact in vitro with cytoskeletal proteins in addition to membranes. The present study examines whether clathrin travels preferentially with the membrane elements or the cytoskeletal elements when it is axonally transported. Guinea pig visual system was labeled with tritiated amino acids. Radioactive SDS-polyacrylamide gel electrophoresis profiles from the major components of transport were coelectrophoresed with clathrin. Only SCb had a band comigrating with clathrin. In addition, radioactive clathrin was purified from guinea pig brain containing only radioactive SCb polypeptides. Kinetic analysis of the putative clathrin band in SCb revealed that it travels entirely within the SCb wave. Thus we conclude that clathrin travels preferentially with the cytoskeletal proteins making up SCb, rather than with the membranes and membrane-associated proteins in the fast component.

Animals↗
PubMed1999

The GDVII strain of Theiler's virus spreads via axonal transport.

Following intracerebral inoculation, the DA strain of Theiler's virus sequentially infects neurons in the gray matter and glial cells in the white matter of the spinal cord. It persists in the latter throughout the life of the animal. Several observations suggest that the virus spreads from the gray to the white matter by axonal transport. In contrast, the neurovirulent GDVII strain causes a fatal encephalitis with lytic infection of neurons. It does not infect the white matter of the spinal cord efficiently and does not persist in survivors. The inability of this virus to infect the white matter could be due to a defect in axonal transport. Using footpad inoculations, we showed that the GDVII strain is, in fact, transported in axons. Transport was prevented by sectioning the sciatic nerve. The kinetics of transport and experiments using colchicine suggested that the virus uses microtubule-associated fast axonal transport. Our results show that a cardiovirus can spread by fast axonal transport and suggest that the inability of the GDVII strain to infect the white matter is not due to a defect in axonal transport.

Animals↗
PubMed1979

[Impairment of rapid axonal transport and concomitant anomaly of smooth endoplasmic reticulum in acrylamide induced neuropathy].

The axonal transport of proteins was studied by radioautography in preganglionic axons of ciliary ganglia in Leghorn chickens treated by acrylamide. The slow axonal transport of proteins was hardly affected. In contrast, the fast axonal transport was severely impaired. Indeed, radioactive proteins accumulated focally at the periphery of several preterminal axons in regions showing a local disorganization of the smooth endoplasmic reticulum which seemed to be one of the earliest changes induced by acrylamide.

Acrylamides↗
PubMed1997

Axonal transport of synaptic vesicle proteins in the rat optic nerve.

The optic nerve, as a part of the central nervous system (CNS), has been used to study axonal transport for decades. The present study has concentrated on the axonal transport of synaptic vesicle proteins in the optic nerve, using the "stop-flow/nerve crush" method. After blocking fast axonal transport, distinct accumulations of synaptic vesicle proteins developed during the first hour after crush-operation and marked increases were observed up to 8 h postoperative. Semiquantitative analysis, using cytofluorimetric scanning (CFS) of immunoincubated sections, revealed that the ratio between distal accumulations (organelles in retrograde transport) and proximal accumulations (organelles in anterograde transport) was much higher (up to 80-90%) for the transmembrane proteins than that for surface adsorbed proteins (only 10-20%). The pattern of axonal transport in the optic nerve was comparable to that in the sciatic nerve. However, clathrin and Rab3a immunoreactivities were accumulated in much lower amounts than that in the sciatic nerve. Most synaptic vesicle proteins were colocalized in the axons proximal to the crush. A differential distribution of synaptobrevin I and II, however, was observed in the optic nerve axons; synaptobrevin I was present in large-sized axons, while synaptobrevin II immunoreactivity was present in most axons, including the large ones. The two isoforms were, thus, partially colocalized. The results demonstrate that (1) cytofluorimetric scanning techniques could be successfully used to study axonal transport not only in peripheral nerves, but also in the CNS; (2) synaptic vesicles are transported with fast axonal transport in this nerve; and (3) some differences were noted compared with the sciatic nerve, especially for Rab3a and clathrin.

Animals↗
PubMed1991

Retrograde axonal transport of the GTP-binding protein Gi alpha: a potential neurotrophic intra-axonal messenger.

When a neuronal target is to provide information to the nucleus of the neurone innervating it, it faces the problem of getting its message up the long length of axon separating the cell body from the site of receptor activation at the terminal. The retrograde axonal transport of the neurotrophic molecule, nerve growth factor (NGF), provided one possible mechanism for this information transfer in the sympathetic nervous system. However, some neurotrophic molecules are not retrogradely transported, indicating the message is carried back by a different mechanism. In this paper, we examined such a novel mechanism mediated by the retrograde axonal transport of the alpha subunit of the second messenger protein, Gi. It is proposed that some non-transported neurotrophic molecules may produce a stable second messenger that is itself transported to the nucleus to convey the target derived information for survival.

Animals↗
PubMed1988

Fast axonal transport of modulatory neuropeptides from central ganglia to components of the feeding system in Aplysia.

The transport of neuropeptides from central ganglia to components of the feeding system was studied in Aplysia. Peptide transport was determined by incubating buccal or cerebral ganglia with 35S-methionine and measuring the appearance of labeled peptides by high-pressure liquid chromatography (HPLC) of extracts of target tissues. Selected nerves were left intact and passed through a Vaseline diffusion barrier separating the ganglia and their targets. Five major labeled peptides were observed to be transported from the buccal ganglia to feeding muscles. They were buccalin, FMRFamide, myomodulin, and 2 small cardioactive peptides. Each of these peptides has been shown to modulate the responses of these muscles to their motor neurons. The peptides were transported by fast axonal transport, as judged by the distance transported and the sensitivity to colchicine. When normalized to correct for differences in total incorporation, the patterns of peptide transport were reproducible between animals. The nature and amount of the peptides transported were different for different muscles. The nature of peptide transport also varied for different nerve groups. These results support the proposition that these 5 peptides act as modulatory transmitters at feeding muscles. No transport of neuropeptides from the cerebral ganglia to feeding muscles was observed, although myomodulin was specifically transported to the buccal ganglia. This suggests that this peptide may play an important role in the previously observed regulation of buccal ganglia activity by neurons in the cerebral ganglia.

Animals↗
PubMed1989

Stable and dynamic forms of cytoskeletal proteins in slow axonal transport.

Dynamic organization of the axonal cytoskeleton was investigated by analyzing slow axonal transport of tubulin and other major cytoskeletal proteins in the motor axons of rat sciatic nerve 1-4 weeks after injection of L-35S-methionine into the anterior horn area of L3-L5 lumbar spinal cord. A large proportion (50-65%) of tubulin transported in the axon was found to be insoluble when extracted with 1% Triton at 4 degrees C. This cold-insoluble tubulin was also resistant to other microtubule-destabilizing agents such as Ca2+, colchicine, and nocodazole, suggesting that it corresponded to the stably polymerized tubulin specific to the axon. From the cold-soluble fraction, microtubules containing a distinct set of associated proteins were recovered by the taxol-dependent procedure. Transport pattern of cold-soluble and -insoluble tubulin in this system showed a time-dependent broadening of the tubulin wave resulting in the appearance of a new faster wave enriched in cold-soluble tubulin. The slower and the faster waves of tubulin were defined as group V or slow component a (SCa) and group IV or slow component b (SCb), respectively, with respect to the 2 subcomponents of slow transport originally described in the optic system. However, compositions of groups IV and V in sciatic motor axons differed significantly from those of the optic system. Actin also exhibited a clear dual wave pattern of transport that coincided well with that of tubulin, indicating that both actin and tubulin were the major components of both groups IV and V.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed2006

Gene targeting of GAN in mouse causes a toxic accumulation of microtubule-associated protein 8 and impaired retrograde axonal transport.

Mutations in gigaxonin were identified in giant axonal neuropathy (GAN), an autosomal recessive disorder. To understand how disruption of gigaxonin's function leads to neurodegeneration, we ablated the gene expression in mice using traditional gene targeting approach. Progressive neurological phenotypes and pathological lesions that developed in the GAN null mice recapitulate characteristic human GAN features. The disruption of gigaxonin results in an impaired ubiquitin-proteasome system leading to a substantial accumulation of a novel microtubule-associated protein, MAP8, in the null mutants. Accumulated MAP8 alters the microtubule network, traps dynein motor protein in insoluble structures and leads to neuronal death in cultured wild-type neurons, which replicates the process occurring in GAN null mutants. Defective axonal transport is evidenced by the in vitro assays and is supported by vesicular accumulation in the GAN null neurons. We propose that the axonal transport impairment may be a deleterious consequence of accumulated, toxic MAP8 protein.

Animals↗
PubMed1989

Interganglionic axonal transport of neuropeptides in Aplysia.

The transport of neuropeptides between central ganglia was studied in Aplysia. Peptide transport was determined by incubating ganglia with 35S-methionine and measuring the appearance of labeled peptides in connected ganglia. Selected interganglionic connectives were left intact and passed through a diffusion barrier separating the ganglia. Labeled peptides transported between ganglia included FMRFamide, myomodulin, and pedal peptide. Each of these peptides has been shown to be physiologically active in Aplysia. In addition to these previously characterized neuropeptides, a number of other as yet uncharacterized labeled peptides were also transported. All the peptides were transported by fast axonal transport as judged by the distance transported and/or the sensitivity to colchicine. Overall, FMRFamide and several unidentified peptides were the predominant transported peptides. However, the nature and amount of the peptides transported differed for each ganglia. These results support the proposition that the labeled peptides have transmitterlike actions and suggest that there are a number of neuropeptides that are likely to have central actions that have not yet been characterized in Aplysia.

Abdomen↗