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At least 667 records · Page 37Linked to original sources
PubMed1988

Axonal transport of the molecular forms of acetylcholinesterase in rats at the onset of diabetes induced by streptozotocin.

During the development of streptozotocin-induced diabetic neuropathy in the rat, the axonal transport of 4 acetylcholinesterase molecular forms was studied by measuring their accumulation on both sides of transected sciatic nerves. Our results indicate that both the anterograde and retrograde axonal transport of all these forms remain normal between 2 and 5 weeks after the induction of diabetes by streptozotocin injection.

Acetylcholinesterase↗
PubMed1972

Axonal transport of gangliosides in the goldfish optic nerve.

Radioactive glucosamine and N-acetylmannosamine injected into the goldfish eye are incorporated into gangliosides that undergo rapid axonal transport to the optic nerve terminals. All ganglioside fractions are labeled. These data provide the first evidence that axonal transport has a role in neuronal ganglioside function and metabolism.

Animals↗
PubMed1980

Impaired retrograde axonal transport from a nerve crush in streptozotocin diabetic rats.

The axonal transport of proteins in crushed nerves of streptozotocin (40 mg/kg) diabetic rats was investigated 4 weeks after induction of diabetes. 35S-methionine was used as a marker for protein and 3H-fucose as a marker for glycoprotein. The precursors were injected into the fifth lumbar spinal ganglion and the accumulation of TCA-insoluble activity proximal and distal to a sciatic nerve ligature was measured at different time intervals after application of a crush. The start of accumulation distal to the ligature was delayed by 1 hour for proteins as well as for glycoproteins. Furthermore, the total amount of accumulated protein after 19 h was decreased by 18% while the decrease was 21% for glycoprotein. By insulin treatment the differences could both be prevented and reversed after 3 days of normoglycaemia. These findings demonstrate an impaired response to a nerve crush and might be the explanation for the regenerative abnormalities of peripheral nerves in diabetes.

Animals↗
PubMed2000

Neurofilaments are non-essential elements of toxicant-induced reductions in fast axonal transport: pulse labeling in CNS neurons.

Acrylamide (ACR) and g-diketones (g-DK) produce distal sensory-motor neuropathy in a variety of species, including humans. The specific molecular site and mechanism of toxicant action leading to specific morphological and behavioral abnormalities requires definition. The relative roles of fast anterograde axonal transport and neurofilaments (NF) are investigated using optic nerves of mice, with and without axonal neurofilaments. Segmental analysis, following pulse labeling with 3H-leucine into the vitreous body, was used to detect changes in fast anterograde transport in the optic nerve and tract. Single injections of ACR significantly reduced the quantity of radiolabeled proteins transported in both transgenic (lacking NF) and non-transgenic (containing NF) mice by 68.4% and 46.2%, respectively. Similarly, single injections of 2,5-hexanedione (2,5-HD) reduced the quantity of radiolabeled transport in transgenic and non-transgenic mice by 55.2% and 47.1%, respectively. Equimolar doses of propionamide and 3,4-hexanedione (non-neurotoxic analogues of ACR and 2,5-HD, respectively) produced no changes in the quantity or apparent rate of optic nerve transport. Additionally, no differences in quantity or apparent rate of transport between transgenic and non-transgenic animals were observed under control or experimental conditions. Therefore, ACR and 2,5-HD reduce the quantity of fast anterograde axonal transport in mouse CNS axons in a comparable amount to previously reported reductions in rat PNS axons. The absence of axonal neurofilaments had no effect on normal fast transport. Furthermore, the presence or absence of neurofilaments did not alter the effect of these toxicants on fast axonal transport. We conclude that toxicant-induced reductions in fast axonal transport are unrelated to ACR and g-diketone effects on NF or their accumulation.

Acrylamide↗
PubMed1989

Axonal transport of neurofilament is accelerated in peripheral nerve during 2,5-hexanedione intoxication.

The neurotoxic compound 2,5-hexanedione (2,5-HD) causes an axonopathy characterized by the presence of neurofilament (NF)-containing enlargements in the preterminal segments of central and peripheral axons. The 2,5-HD axonopathy is a good model for human acquired and inherited giant axonal neuropathies. Recently, we reported that following 2,5-HD administration, axonal transport of NF is markedly and selectively accelerated in the primary visual system. We have now studied slow axonal transport in the sciatic system of rats intoxicated with 0.5% 2,5-HD in drinking water. Following radiolabeling, transported proteins were examined after polyacrylamide gel electrophoresis and fluorography. The bulk of radiolabeled NF subunits was located 30-50 mm from the spinal cord in 2,5-HD treated animals and 10-25 mm in controls. The rate of transport of the three NF subunits was 0.7 mm/day in controls and 1.2 mm/day in 2,5-HD treated animals. The rate of transport of tubulin was not significantly changed. Electrophysiological studies of soleus nerve and muscle showed no evidence of denervation after 6 weeks of intoxication. It is concluded that, following 2,5-HD administration, transport of NF is preferentially accelerated in both central and peripheral axons. A pathogenetic mechanism based on the acceleration of NF transport is proposed, which may explain the formation and the distal or proximal location of NF-containing axonal enlargements in giant axonopathies.

Action Potentials↗
PubMed1987

Axonal transport and tissue contents of substance P in rats with long-term streptozotocin-diabetes. Effects of the aldose reductase inhibitor 'statil'.

This study examined the axonal transport of substance P-like immunoreactivity (SPLI) and its content in dorsal root ganglion, trigeminal ganglion, stomach and ileum of non-diabetic rats and two groups of rats with streptozotocin-induced diabetes of 9 months duration. One diabetic group received the aldose reductase inhibitor 'Statil' throughout the period of study. To reduce morbidity all diabetic animals were given twice-weekly injections of a long-acting insulin which restricted weight loss but did not prevent regular and severe hyperglycaemia. Axonal transport of SPLI was studied by measurement of accumulation at 12 h ligatures on the left sciatic nerve. There were no differences between the 3 groups either in the calculated anterograde and retrograde mean rates of accumulation (ranges 6.0 to 7.6 and 0.38 to 0.72 mm/h respectively) or mobile fractions of SPLI (means from 0.54 to 0.58). There were, however, marked reductions in anterograde and retrograde accumulations of SPLI in the constricted nerves of the 'untreated' diabetics (respectively 57 and 33% of controls; P less than 0.01 for both). In the 'Statil'-treated rats these deficits were attenuated (80 and 75% of controls). Diabetes also reduced the SPLI content of unligated sciatic nerve and trigeminal ganglion (65 and 75% of controls). 'Statil' prevented the deficit in the ganglion, but not in the nerve. 'Statil' treatment prevented the myo-inositol depletion and attenuated the sorbitol and fructose accumulation seen in the sciatic nerves of the untreated diabetic animals suggesting effective inhibition of aldose reductase in this tissue. The total SPLI content of the stomach and 1-cm segments of ileum were unaltered in the diabetic animals but due to the increased weights of these tissues the SPLI content per unit weight was reduced. These changes were unaffected by 'Statil'.

Aldehyde Reductase↗
PubMed1980

Cellular synthesis and axonal transport of gamma-aminobutyric acid in a photoreceptor cell of the barnacle.

1. [3H]glutamate or [3H]gamma-aminobutyric acid (GABA) was injected into the photoreceptor cell of the lateral ocellus of Balanus eburneus, in order to study the transmitter substance of the cell. 2. The photoreceptor cell synthesized [3H]GABA from injected [3H]glutamate. 3. The newly formed [3H]GABA moved inside the photoreceptor axon towards the axon terminal with a velocity of about 0.9 mm/hr. Injected [3H]GABA moved at 0.9 mm/hr and also at 0.4 mm/hr. 4. Axonally transported [3H]GABA reached the axon terminal within several hours following the injection. It did not accumulate at the terminal, but gradually disappeared. 5. Light-microscope and electron-microscope autoradiography following the injection of [3H]GABA revealed that [3H]-reacted silver grains were present in a certain type of axon terminal. The terminal thus identified as that of a photoreceptor cell contains many clear, polymorphic synaptic vesicles about 300-500 A in diameter, some dense-cored vesicles 700-1300 A in diameter, and glycogen granules. The terminal forms many synapses, and each synapse has a synaptic dense body. The terminal always faces two post-synaptic elements at the synapse, forming a triad with a gap distance of about 160-200 A. 6. A GABA analogue, [3H]di-aminobutyric acid, was selectively taken up into the terminals previously identified as those of photoreceptors. 7. These results support the notion that the transmitter substance of the photoreceptor cell of the barnacle is GABA.

Animals↗
PubMed1988

Monoclonal anti-Thy 1 antibody (OX7) is axonally transported in rat nervous system.

Monoclonal anti-Thy 1 antibody (OX7) was pressure microinjected into vagus nerve, tongue or caudate nucleus of rats. Indirect anti-IgG immunoperoxidase staining showed that OX7 was axonally transported antero- and/or retrogradely from all injection sites. Histological examination and behavioral observations did not reveal neurotoxicity from these single OX7 injections. We conclude OX7 may prove useful as a carrier for selectively targeting molecules at neurons via endocytosis and axonal transport.

Animals↗
PubMed1989

Axonal transport and localization of B-50/GAP-43-like immunoreactivity in regenerating sciatic and facial nerves of the rat.

Neurons that can regenerate their axons following axotomy increase their synthesis and axonal transport of a growth-associated protein, called GAP-43, which has been shown to be identical to the synaptic phosphoprotein B-50. The function of B-50/GAP-43 to the process of regeneration is unknown. We used a polyclonal, affinity-purified antibody against B-50 to study the axonal transport and localization of B-50/GAP-43-like immunoreactivity (B50LI) in the regenerating sciatic and facial nerves of adult rats. Quantitative data were obtained by densitometry of the B-50 band in immunoblots of nerve segments, which had been run on SDS-polyacrylamide gels. In the regenerating sciatic nerve, anterograde accumulation at a collection ligature was 3.0 times higher than retrograde accumulation. The mobile fraction of B50LI was only 0.28 of total B50LI and traveled with a mean anterograde velocity of 5.3 mm/hr. B50LI distribution in the newly regenerated portion of the nerve revealed maximal B50LI levels midway between the position of the crush and the fastest-growing axons. Immunocytochemistry of this portion of the nerve demonstrated B50LI to be associated with regenerating axons but also to a large extent with extra-axonal structures outlining the Schwann cell bands of Büngner. This zone of B50LI-positive Schwann cell bands was found to extend more distally in nerves in which regeneration had processed longer, e.g., up to 5 mm distal to the crush after 3 d and 8 mm after 4 d. Further distal to this zone, many fine regenerating axonal profiles could be detected with B-50 antibody, but were neurofilament negative. These findings raise the possibility of an extra-axonal function of B-50/GAP-43, as this protein might be secreted from regenerating axons and might play a role in axon-Schwann cell interactions during axonal maturation.

Animals↗
PubMed1980

Analysis of the mechanism of fast axonal transport by intracellular injection of potentially inhibitory macromolecules: evidence for a possible role of actin filaments.

Although actin is thought to participate in several types of cell motility other than muscle contraction, no direct evidence has linked it to the force-generating mechanism for fast axonal transport. We have obtained evidence for the involvement of actin by microinjecting, into the serotonergic giant cerebral neuron of Aplysia, two preparations that have been shown to depolymerize actin filaments. One is a fraction of rabbit serum containing a heat-labile gamma globulin that affects actin polymerization in a manner similar to that of cytochalasin and several proteins that are thought to regulate the length of actin filaments. The other is bovine pancreatic DNase I which binds to actin stoichiometrically. Both preparations substantially decreased the transport of storage vesicles containing [3H]serotonin. Phalloidin, a toxic fungal peptide that binds to actin filaments but stabilizes rather than depolymerizes them, did not inhibit transport. We have not yet determined whether the inhibition od transport occurs during export of [3H]serotonin from the cell body into the axon or during translocation along the axon. Nevertheless, these observations provide a promising experimental indication that actin is involved in fast axonal transport.

Actins↗
PubMed1999

Increased expression, axonal transport and release of pituitary adenylate cyclase-activating polypeptide in the cultured rat vagus nerve.

The expression and axonal transport of pituitary adenylate cyclase-activating polypeptide (PACAP) was studied in the cultured vagus nerve of the rat by immunocytochemistry and in situ hybridization. The number of neurons immunoreactive for PACAP increased markedly within the nodose ganglion during a 24-48 h culture period, as did the number of cells containing messenger RNA for PACAP. PACAP was found to be axonally transported and accumulated at the site of a crush injury. The peptide was also released at this site. Addition of PACAP to regenerating nerves in culture did not affect axonal outgrowth, neither did antibodies against PACAP. Separate experiments showed that neither PACAP-27 nor PACAP-38 affected proliferation of non-neuronal cells measured as the incorporation of [3H]thymidine. In contrast, forskolin, another potent stimulator of adenylate cyclase besides PACAP, dramatically decreased [3H]thymidine incorporation. The results showed that, during regeneration of peripheral nerves, PACAP expression increases and the peptide is transported into the regenerating nerve, where it is released. The functional significance of this release is unknown, but it does not seem to be directly related to the initiation of proliferation of Schwann cells or initial axonal outgrowth.

Animals↗
PubMed1986

Characterization of retrograde axonal transport of antibodies in central and peripheral neurons.

Retrograde axonal transport of antibodies against synaptic membrane glycoproteins was studied in the hypoglossal nerve and several CNS pathways of the rat. Injection into the tongue of polyclonal antibodies against synaptic membrane glycoproteins produced immunocytochemically labeled cells in the hypoglossal nucleus 4-5 hr later. Immunoreactive staining increased through 48 hr after injection and then declined. Injections of Fab preparations of the antibody gave labeling patterns indistinguishable from those of the whole antibody. The specificity of this method is shown by control studies in which antibodies against antigens that are not known to be present on the surface of presynaptic membranes were injected and gave no retrograde labeling. Retrograde labeling was also demonstrated in CNS pathways. However, labeling was never as intense as that seen in the hypoglossal nucleus, and some CNS pathways failed to show any retrograde labeling. Furthermore, retrograde labeling after control injections could be demonstrated in some cases. To determine if antibodies were also transported anterogradely, injections were made into the vitreous body of the eye, and the superior colliculus was processed for immunocytochemistry. Unlike wheat-germ agglutinin and several other tracers, antibodies were not found to be anterogradely transported in the optic nerve.

Animals↗
PubMed1981

On the mechanism of the inhibition of fast axonal transport caused by exposure of frog spinal ganglia to the sodium-deficient medium.

Substitution of choline or sucrose for Na+ in the medium surrounding frog spinal ganglia causes an inhibition of fast axonal transport in vitro. Since an increase Ca2+ influx into neurons does occur in these media, the present experiments examined the possibility that the effect on transport is mediated by an increase in intracellular free Ca2+. The combination of the choline substitution with a 3-fold increase in extracellular Ca2+ reduced transport of [3H] proteins to 75% of control (as compared to the 63% obtained previously with choline alone), thus providing no evidence of an enhancement of choline's effect by a second factor which promotes an increase in intracellular Ca2+. When Li+ was substituted for Na+, the quantity of [3H] proteins transported fell to 40% of control despite the fact that the Li+ substitution does not modify Ca+ fluxes across the plasma membrane in neurons of the frog spinal nerve. The present findings suggest that removal of Na+ interferes with fast axonal transport by a mechanism other than an increase in intracellular Ca2+

Animals↗
PubMed1994

A rapid anterograde axonal transport of carboxypeptidase H in rat sciatic nerves.

Using the highly sensitive HPLC-fluorophotometry technique, anterograde and retrograde axonal transport of carboxypeptidase H (CPH), a putative prohormone processing enzyme that removes a basic amino acid from the C-terminus of a precursor peptide, was measured 12-72 h after double ligations of rat sciatic nerves. CPH-like activity in rat sciatic nerves was 60-fold lower than that in the pituitary gland. CPH-like enzyme activity was rapidly accumulated in the proximal segment and peaked 48 h after ligation. The axonal flow was 100 mm/day, indicating that CPH in rat sciatic nerves is rapidly transported to the nerve terminals as an active form. The properties of the enzyme were similar to those of CPH in the brain: The pH optimum is at 5.5, and the molecular mass is approximately 5 kDa. These results suggest that active CPH in the PNS is transported by a rapid anterograde axonal flow and may play a role in converting proneuropeptides to active neuropeptides under the axonal transport.

Animals↗
PubMed1994

Blockade of neurotensin receptors by the antagonist SR 48692 partially prevents retrograde axonal transport of neurotensin in rat nigrostriatal system.

The effect of SR 48692, a potent and selective non-peptide antagonist of the neurotensin receptor, was investigated on the retrograde axonal transport of neurotensin in the rat nigrostriatal dopamine pathway. When rats were injected in the striatum with (3-[125I]iodotyrosyl3)neurotensin, a substantial accumulation of radioactivity appeared in the ipsilateral substantia nigra 1.5 h after injection, and highest levels (336 +/- 23 dpm/mg of protein) were observed 2.5-3.5 h after the injection. The phenomenon required a pretreatment of the animals with thiorphan (30 micrograms) an inhibitor of endopeptidase. The amount of radioactivity accumulated (3.5 h) was found to be reduced (25%) by local (100 nM) or peripheral administration of SR 48692 (5, 10, 20 mg/kg, i.p.; 25%, 40%, 40%, respectively). Our results indicate that blockade of neurotensin receptors by a selective non-peptide receptor antagonist affects the retrograde axonal transport of the tridecapeptide, and further suggest the notion that this process involves neurotensin receptors.

Animals↗
PubMed1993

Vesicular fast axonal transport rates in young and old rat axons.

An isolated sciatic nerve preparation was used to measure the transport rates of more than 18,000 vesicles in 72 axons from young (3-4 months of age) and old (24-26 months of age) rats from two strains (Harlan Sprague-Dawley and Fisher-344). Average anterograde and retrograde vesicle transport rates were significantly slower in the older animals. The amount of slowing of anterograde vesicles was twice as great as the slowing of retrograde vesicles. Age-related slowing of vesicle transport was inversely proportional to vesicle speed, with the result that transport of the slowest and largest vesicles may essentially be blocked in older axons. One possible explanation for these data is that long-lived axonal cytoskeletal proteins are subject to age-related changes that impede vesicle transport.

Aging↗
PubMed1975

Rôle of axonal transport in maintaining central synaptic connections.

Synaptic boutons on the somata of rat hypoglossal neurones have been stained with Zinc Iodide-Osmium, and counted using light microscopy. Two weeks after Silastic cuffs containing colchicine or vinblastine were applied to the hypoglossal nerve, the number of boutons on parent nerve cell bodies was significantly lower than controls. These drugs inhibited retrograde axonal transport of horseradish peroxidase, but did not affect neuromuscular conduction or the number of axons in the nerve trunk. Cuffs containing lignocaine did not affect boutons or axonal transport significantly.

Animals↗
PubMed1988

Cold blockade of axonal transport activates premitotic activity of Schwann cells and wallerian degeneration.

Between 3 and 4 days after transection of cat sciatic nerve, Schwann cell-associated premitotic activity spreads anterogradely along degenerating distal nerve stumps at a rate of approximately 200 mm/day. We investigated whether fast anterograde axonal transport contributes to the initiation of this component of Wallerian degeneration. Axonal transport was blocked in intact and transected cat sciatic nerves by focally chilling a proximal segment to temperatures below 11 degrees C for 24 hr. Incorporation of [3H]thymidine (a marker of premitotic DNA synthesis) was then measured 3 and 4 days posttransection in cold blocked- and control-degenerating nerves. Effects of cold block prior to and concomitant with nerve transection were studied. Results failed to support the hypothesis that Schwann-cell premitotic activity after axotomy is associated with entry into the axon of mitogenic substances and their anterograde fast transport along the distal stump. Instead, data suggested that progressive anterograde failure of fast anterograde transport distal to transection serves to effect the Schwann-cell premitotic response to axotomy.

Animals↗