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 19 recordsLinked to original sources
PubMed1988

Effects of taxol on slow and fast axonal transport.

Axonal transport of tubulin in the rat sciatic nerve is almost completely inhibited by a single subepineural injection of taxol, without affecting that of neurofilament proteins. Actin and a large number of polypeptides cotransported with actin as minor components are also blocked by taxol, although to a lesser extent. Fast axonal transport is essentially free from the inhibitory effect of this drug. Although previous models have suggested that slow axonal transport involves the bulk movement of cytoskeletal structures, these results suggest that such transport may involve an equilibrium between polymerised and depolymerised forms of the axonal cytoskeleton.

Actins↗
PubMed1977

Axonal transport and axonal processing of low molecular weight proteins from the abdominal ganglion of Aplysia.

Axonal transport of proteins in nerves of the abdominal ganglion of Aplysia was observed after a 2 h incubation of the ganglion in tritiated amino acids. The transported proteins migrate as a series of discrete peaks, all apparently moving at a rate of 3 mm/h. This process is sensitive to both colchicine and vinblastine, the former agent reducing the amount of transported material without affecting the transport rate. The molecular weight distribution of the transported proteins, as revealed by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate (SDS), is basically unchanged for up to 20 h after labeling. Low molecular weight species (less than or equal to 18,000 daltons) make up 10-20% of the transported protein and appear to be enriched in leucine. These proteins undergo proteolytic cleavage during transport, eventually reaching a molecular weight of 3000 daltons or lower. It is suggested that these data reflect the axonal transport and processing of neurosecretory peptides synthesized by identifiable neurons of the ganglion.

Animals↗
PubMed1986

Nerve repair and axonal transport. Distribution of axonally transported proteins during maturation period in regenerating rabbit hypoglossal nerve.

The distribution of fast migrating [3H]leucine-labelled proteins was studied in transected and repaired rabbit hypoglossal nerves. The nerves were repaired 90 days earlier with mesothelial chamber or epineurial suture technique. Fast migrating radiolabelled proteins were transported into the distal nerve segment and neurophysiological recordings from the tongue as well as the presence of myelinated axons in the distal nerve segment verified successful regeneration. The total amount of radioactivity was increased in repaired nerves as compared to contralateral nerves. In both groups there was a significant accumulation of radiolabelled proteins at the site of lesion. Nerves repaired with mesothelial chambers showed significantly more radioactivity in the distal nerve segment as compared to sutured nerves. The present study indicates long-standing effects on axonal transport system after both types of nerve repair. It is our opinion that axonal transport studies are a valuable complement when evaluating experimental nerve repair.

Animals↗
PubMed1979

Taurine in the developing rabbit visual system: changes in concentration and axonal transport including a comparison with axonally transported proteins.

[35S]Taurine injected intravitreally into rabbits was transported axonally to the optic nerve terminals. Considerably more [35S]taurine was transported in young rabbits than in mature rabbits. The time course of taurine transport did not parallel that of proteins labeled with [3H]proline in the same system. The concentration of taurine in all components of the visual system, except retina, was greater in young animals than in mature animals, and was especially high in optic nerve. The possible functions of the high concentrations of taurine and the greater amount of axonally transported taurine in developing mammalian CNS are discussed.

Age Factors↗
PubMed1979

Continuation of fast axonal transport in regenerating axons in vitro.

A previous study by McLean and co-workers reported that regenerating axons of the rabbit vagus nerve were unable to sustain axonal transport in vitro for several months after nerve injury. In contrast, we found that sensory axons of the rat sciatic nerve were able to transport 3H-labeled protein into their regenerating portions distal to the site of injury within a week after injury when placed in vitro. Transport in vitro was not significantly less than transport in axons maintained in vivo for the same period. Transport occurred in the medium that was used by the McLean group, but was significantly reduced in calcium-free medium. When axon regeneration was delared, only small amounts of activity were present in the nerve distal to the site of injury, showing that labeled protein normally present in that part of the nerve was associated with axons and was not a result of local precursor uptake by nonneural elements in the sciatic nerve. We were not able to explain the failure of McLean and co-workers to demonstrate transport in vitro in regenerating vagus nerve, but we conclude that there is no general peculiarity of growing axons that makes them unable to sustain transport in vitro.

Animals↗
PubMed1990

[Abnormalities of axonal transport as pathogenesis of axonal degeneration in peripheral neuropathy].

Axonal transport is a universal property of nerve cells. Role of axonal transport abnormalities in the pathogenesis of peripheral neuropathies was discussed. Applications of isotope-labeling technique to the study of axonal transport in experimental neuropathy have provided insights into the pathogenesis of axonal degeneration. As a model of dying-back neuropathy, axonal transport has been studied in sciatic motor neurons of rats with neuropathy induced by p-bromophenylacetylurea (BPAU) using this technique. The velocity of rapid anterograde transport was unaffected in this neuropathy and amount of retrograde axonal transport was reduced. The lag time between precursor injection and the onset of transport was shorter in BPAU-treated rats than controls. Whereas, in experimental ethylene oxide (EO) neuropathy rats, rapid transport velocity was markedly reduced in spite of very mild results of morphometric study. Those rapid axonal transport abnormalities may explain some aspects of the pathogenesis of peripheral neuropathies. In BPAU neuropathy model, disturbance of assembly of membrane-limited vesicles in Golgi processing may play a role in turnaround defect which causes dying-back neuropathy. EO neuropathy model suggests the possibility of oxygen utilization disturbance may causes energy dependent rapid transport velocity. Moreover, environments surrounding axon are also important for function of axonal transport. Present information leads to the conclusion that abnormalities in the supply and deposition of transported materials occur in early course of peripheral neuropathy and may contribute to development of the neuropathy.

Animals↗
PubMed1991

The axonal transport motor 'kinesin' is bound to anterogradely transported organelles: quantitative cytofluorimetric studies of fast axonal transport in the rat.

Monoclonal antibodies to the axonal transport ATPase kinesin were used in an immunofluorescent study on mammalian nerves. Following crushing of the sciatic nerve and the ventral roots of adult rats, immunoreactive material was found to accumulate rapidly, mainly proximal to a crush but also, to some degree, distal to a crush. The strongest immunofluorescence was observed after incubation with the H2 antibody against the heavy subunit of kinesin. Using the cytofluorimetric scanning (CFS) procedure, the accumulated amounts were quantified and it was found that the retrogradely accumulating kinesin-like immunoreactivity (IR) was about 4-12% of the anterogradely transported kinesin-IR. The results were compared to the vesicle marker p38 (synaptophysin), which was found to accumulate to a significant extent on both sides of the crush. Cytofluorimetric scanning measurements indicated that nearly 50% of the anterogradely accumulated p38-IR was recycling to the cell body. The results demonstrate that kinesin in the living axon is affiliated with anterogradely transported organelles. Retrogradely transported organelles appeared to carry very little kinesin-IR, suggesting that kinesin may be subject to turnover, distinct from that of p38, in the distal regions of the axon.

Adenosine Triphosphatases↗
PubMed1992

Growth cones of regenerating adult sciatic sensory axons release axonally transported proteins.

Labelled, rapidly transported axonal proteins were shown to be released from adult frog sciatic sensory neurons, regenerating in vitro after a crush injury. The spatial distribution of the transported, released proteins could accurately be resolved by culturing the nerve on nitrocellulose paper, which trapped the released proteins. The release was located to the crush and to the entire outgrowth region. When regeneration was inhibited by adenosine, the release was limited to the crush site, implying that the release was linked to the growing axons. Other experiments suggested that the release emanated from growth cones. Furthermore, two-dimensional electrophoretical analysis of both fast axonally transported and of released proteins showed that the latter represented a selection of the transported protein species.

Adenosine↗
PubMed1990

Precursor of amyloid protein in Alzheimer disease undergoes fast anterograde axonal transport.

In the brains of aged humans and cases of Alzheimer disease, deposits of amyloid in senile plaques are located in proximity to nerve processes. The principal component of this extracellular amyloid is beta/A4, a peptide derived from a larger amyloid precursor protein (APP), which is actively expressed in brain and systemic organs. Mechanisms that result in the proteolysis of APP to form beta/A4, previously termed beta-amyloid protein, and the subsequent deposition of the peptide in brain are unknown. If beta/A4 in senile plaques is derived from neuronally synthesized APP and deposited at locations remote from sites of synthesis, then APP must be transported from neuronal cell bodies to distal nerve processes in proximity to deposits of amyloid. In this study, using several immunodetection methods, we demonstrate that APP is transported axonally in neurons of the rat peripheral nervous system. Moreover, our investigations show that APP is transported by means of the fast anterograde component. These findings are consistent with the hypothesis of a neuronal origin of beta/A4, in which amyloid is deposited in the brain parenchyma of aged individuals and cases of Alzheimer disease. In this setting, we suggest that APP is synthesized in neurons and delivered to dystrophic nerve endings, where subsequent alterations of local processing of APP result in deposits of brain amyloid.

Acetylcholinesterase↗
PubMed1988

Axonal transport of angiotensin-converting enzyme in the rat striatonigral pathway.

We analyzed the transport of angiotensin-converting enzyme (kininase II, EC 3.4.15.1) in the striatonigral pathway by quantitative autoradiography using the specific converting enzyme inhibitor, 125I-351A. 125I-351A binding was studied at different time intervals after knife cut lesions of the striatonigral pathway. Twenty-four h after the lesion, accumulations of 125I-351A binding sites were observed both rostral and caudal to the lesioned site. No change in 125I-351A binding was observed at this time in the caudate putamen and substantia nigra. Ten days after the lesion, a significant decrease (58%) in 125I-351A binding was found in the pars reticulata of the ipsilateral substantia nigra. These results suggest that the angiotensin-converting enzyme is transported axonally in the rat striatonigral pathway.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

Differential extraction of axonally transported proteoglycans.

Axonally transported proteoglycans were differentially solubilized by a sequence of extractions designed to infer their relationship to nerve terminal membranes. Groups of goldfish were injected unilaterally with 35SO4 and contralateral optic tecta containing axonally transported molecules were removed 16 h later. Tecta were homogenized in isotonic buffer and centrifuged at 100,000 g for 60 min to create a "total supernatant" fraction. Subsequent homogenizations followed by recentrifugation were with hypotonic buffer (lysis extract), 1 M NaCl, Triton X-100 or alternatively Triton-1 M NaCl. Populations of proteoglycans in each extract were isolated on DEAE ion exchange columns and evaluated for content of glycosaminoglycans (GAGs). Results show the distribution of transported proteoglycans to be 26.3% total soluble, 13.7% lysis extract, 13.8% NaCl extract, 12.2% Triton extract, and 46.2% Triton-NaCl extract. Proteoglycans from all fractions contained heparan sulfate as the predominant GAG, with lesser amounts of chondroitin (4 or 6) sulfate. The possible localizations of transported proteoglycans suggested by the extraction results are discussed.

Animals↗
PubMed1989

The role of dynein in retrograde axonal transport.

Fast axonal transport is manifested at the sub-cellular level as the anterograde or retrograde movement of membrane-bounded organelles along microtubules. Earlier work implicated the protein kinesin as the motor for anterograde axonal transport. More recent work indicates that a brain microtubule-associated protein, MAP 1C, is responsible for retrograde transport. Of additional interest, MAP 1C has been found to be a cytoplasmic form of the ciliary and flagellar ATPase dynein, indicating a much more general functional role for this enzyme in cells than had been suspected.

Adenosine Triphosphatases↗
PubMed1989

Selective axonal transport in a single cholinergic axon of Aplysia--role of colchicine-resistant microtubules.

Substance-specific selective axonal transport was examined in a single axon by injecting [3H]leucine and [14C]acetylcholine simultaneously into the cell body of a giant cholinergic neuron (R2) in the abdominal ganglion of Aplysia kurodai. The ganglion and attached nerves were cultured for several hours after the injection and the migration of radioactive substances along the axons of the injected neuron was examined. The substances examined were 3H labeled membrane proteins and soluble proteins synthesized in the cell body, 14C labeled bound acetylcholine formed in the cell, injected [3H]leucine and soluble [14C]acetylcholine. Membrane proteins and bound acetylcholine (plus a part of soluble acetylcholine) moved along the axon somatofugally at maximum velocities of 2.4 and 1.7 mm/h, respectively, at 25 degrees C. Soluble proteins, free leucine and most of the soluble acetylcholine did not move by fast axonal transport but diffused inside the axon of the neuron R2 at rates predicted from their expected diffusion constants in the axoplasm [Koike H. and Nagata Y. (1979) J. Physiol. 295, 397-417]. The diffusion kinetics of these substances were analysed and used for determination of true axon length, and to separate axonal transport components from diffusing components. An antimitotic drug, colchicine, selectively suppressed the axonal transport of membrane proteins but not of acetylcholine at 1-5 mM concentration, though it finally blocked the axonal transport of acetylcholine at 20 mM. When 1-5 mM colchicine was separately perfused only to the distal axon of the neuron R2, the migration of membrane proteins was stopped just proximal to the colchicine perfusion zone but acetylcholine migration was not disturbed by the drug. The moving component of acetylcholine was recovered by sucrose density centrifugation from a compartment previously reported as that of vesicular acetylcholine. As a possible mechanism of this selective axonal transport, it is proposed that there are two groups of microtubules: a colchicine-sensitive group of microtubules which may transport membrane proteins, and a colchicine-resistant group which may preferentially transport the transmitter substance acetylcholine at a slower rate.

Acetylcholine↗
PubMed1985

Axonal transport of cytoskeletal proteins in aluminum toxicity. Aluminum toxicity and axonal transport.

Aluminum administration in certain species results in the accumulation of neurofilament bundles within the neuronal perikaryon and the proximal neuronal processes. The study presented here was designed to investigate how aluminum exerts its effects on the neuronal cytoskeleton. Microinjections of AlCl3 were administered directly to the rabbit lumbar spinal cord; the injections resulted in the accumulation of neurofilament bundles in upwards of 80% of the anterior horn cells. Approximately 7 d later, [35S]methionine was administered to the same region, and exactly 14 d after the radioactive pulse the animals were sacrificed. Sequential 3-mm segments of the sciatic nerves beginning at the root exit zone were processed for gel electrophoresis and fluorography. The counts incorporated into gel bands representing actin, tubulin, and the neurofilament (NF) subunits were determined for each segment, and a distribution curve for the pooled control and pooled aluminum-treated rabbits was constructed. The distribution curves for the two groups, separately analyzed for each cytoskeletal protein, did not significantly differ using an analysis of variance. We conclude that an interruption of slow axonal transport does not occur in this model of aluminum-induced lumbar myelopathy.

Aluminum↗
PubMed1988

Progressive deficits in retrograde axon transport precede degeneration of motor axons in acrylamide neuropathy.

Single injection of acrylamide (1.3 mmol/kg, i.p.) inhibited retrograde axon transport of [125I]tetanus toxin in hen sensory and motor axons. Retrograde axon transport deficits appeared within hours of dosing with acrylamide. The inhibitory effect of acrylamide on retrograde axon transport was transient since transport deficits were not detectable 35 h after dosing. Acrylamide impaired the retrograde movement but not the uptake of [125I]tetanus toxin in the axon. Multiple doses of acrylamide (0.42 mmol/kg, i.p.) induced progressive clinical signs of acrylamide neuropathy that correlated with increasing deficits in retrograde axon transport of [125I]tetanus toxin to ventral spinal cord. Deficits were also observed in sensory neurons but were not statistically significant. Accumulated decrements in retrograde axon transport may be the underlying cause of degeneration of motor axons in acrylamide neuropathy in fowl.

Acrylamide↗
PubMed1986

The kinematics of turnaround and retrograde axonal transport.

Rapid axonal transport of a pulse of 35S-methionine-labelled material was studied in vitro in the sensory neurons of amphibian sciatic nerve using a position-sensitive detector. For 10 nerves studied at 23.0 +/- 0.2 degrees C it was found that a pulse moved in the anterograde direction characterized by front edge, peak, and trailing edge transport rates of (mm/d) 180.8 +/- 2.2 (+/- SEM), 176.6 +/- 2.3, and 153.7 +/- 3.0, respectively. Following its arrival at a distal ligature, a smaller pulse was observed to move in the retrograde direction characterized by front edge and peak transport rates of 158.0 +/- 7.3 and 110.3 +/- 3.5, respectively, indicating that retrograde transport proceeds at a rate of 0.88 +/- 0.04 that of anterograde. The retrograde pulse was observed to disperse at a rate greater than the anterograde. Reversal of radiolabel at the distal ligature began 1.49 +/- 0.15 h following arrival of the first radiolabel. Considerable variation was seen between preparations in the way radiolabel accumulated in the end (ligature) regions of the nerve. Although a retrograde pulse was seen in all preparations, in 7 of 10 preparations there was no evidence of this pulse accumulating within less than 2-3 mm of a proximal ligature; however, accumulation was observed within less than 5 mm in all preparations.

Animals↗
PubMed1987

Vacor neuropathy: ultrastructural and axonal transport studies.

Distal axonal degeneration has been correlated with abnormalities of fast axonal transport in several toxic neuropathies. We have investigated axonal transport in experimental PNU (N-3-pyridylmethyl-N'-p-nitrophenylurea; Vacor) neuropathy, because of the rapid and synchronous degeneration of many terminal axons after a single dose of PNU. Almost all axon terminals at neuromuscular junctions in hindfoot muscles degenerated by 24 hours after the administration of PNU. Fewer affected axons were found in intramuscular nerve twigs, and fewer still in the posterior tibial nerves. No abnormal myelinated axons were found in the sciatic nerve in the thigh. Fast axonal transport in the sciatic nerve remained normal to the mid-thigh, but a reduced amount of labeled transported material reached the posterior tibial nerve at the ankle (27% reduction). Autoradiography showed that nearly no transported material reached the intramuscular nerves and neuromuscular junctions of the hindfeet. These results suggest that toxic impairment of fast anterograde axonal transport may contribute to the axonal degeneration produced by PNU.

Animals↗
PubMed1992

Acrylamide exposure preferentially impairs axonal transport of glycoproteins in myelinated axons.

The right L5 dorsal root ganglion of adult rats exposed to acrylamide (40 mg/kg body weight/day for nine consecutive days) was injected with either [3H]methionine or [3H]glucosamine. After allowing incorporation into macromolecules and axonal transport to proceed for 5 hr, the distribution of radioactivity in cross sections and longitudinal sections of sciatic nerve was determined by autoradiography. Control and treated animals showed no difference in distribution of label within the sciatic nerve with respect to rapidly transported proteins labelled with [3H]methionine. In control animals the distribution of rapidly transported glycoproteins labelled with [3H]glucosamine was similar to that found for [3H]methionine-labelled proteins. In contrast, acrylamide-exposed rats had a very different distribution of labelled glycoproteins; there was a marked paucity of label in the myelinated axons. We interpret this result as indicating that acrylamide preferentially inhibits glycosylation or axonal transport of glycoproteins in neurons bearing myelinated axons.

Acrylamide↗