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At least 631 records · Page 35Linked to original sources
PubMed2000

Polyol metabolism of retrograde axonal transport in diabetic rat large optic nerve fiber.

PURPOSE: The role of the polyol pathway metabolism in progressive impairment of retrograde axonal transport was evaluated in the optic nerve of rats with streptozotocin-induced diabetes. METHODS: Rats with streptozotocin-induced diabetes received a low (3 mg/kg body weight) or high dose (10 mg/kg body weight) of oral aldose reductase inhibitor (ARI). At 1 and 3 months after induction of diabetes, Fluoro-Gold (FG, Chemicon, Temecula, CA) was injected into the dorsal lateral geniculate nucleus. Percentages of FG-labeled large, medium, and small retinal ganglion cells (RGCs) per total population were calculated in the retinas of ARI-treated diabetic, untreated diabetic, and normal control rats. RESULTS: Mean percentages of FG-labeled large RGCs per total population were significantly decreased in nontreated diabetic rats compared with control animals at 1 month of induced diabetes. This decrease in FG labeling was not observed in both the low- and high-dose ARI-treated diabetic rats. At 3 months of induced diabetes, FG labeling of both large and medium RGCs was significantly decreased. This decrease was completely ameliorated by high-dose ARI treatment. CONCLUSIONS: These results indicate that diabetes affects retrograde axonal transport progressively through selective impairment of RGCs and that the polyol pathway metabolism is involved in such impairment.

Aldehyde Reductase↗
PubMed1978

Axonal transport of 4S RNA in the chick optic system.

The axonal transport of tRNA has been investigated in the chick optic system. Chicks were injected with [3H]uridine intraocularly or intracranially and the RNA of the retina, nerve complex, and tecta separated by polyacrylamide gel electrophoresis and then counted. The ratio of tRNA to rRNA specific activities increased with time in both the nerve complex and contralateral tectum. The ratio increased more rapidly in the nerve complex than the tectum. However, no increase was observed in the case of intracranially injected animals. This is consistent with the axonal flow of tRNA. When [methyl-3H]methionine was used as precursor, the preferential labeling of 4S RNA to rRNA which resulted more clearly showed a transport of 4S RNA from the retinal cells to the tectum. In conclusion, it was found that about 40% of the radioactive RNA observed within the optic tectum 4 days after an intraocular injection of [3H]uridine was accounted for by 4S RNA which has flowed from the retina. However, the migration of a methylated RNA molecule of size 4S, but unrelated to rRNA, cannot be entirely eliminated.

Animals↗
PubMed1993

Direct projections from the cerebellar fastigial nucleus to the thalamic suprageniculate nucleus in the cat studied with the anterograde and retrograde axonal transport of wheat germ agglutinin-horseradish peroxidase.

Axonal transport of WGA-HRP injected into (1) the suprageniculate nucleus or (2) the fastigial nucleus, was investigated. Retrogradely labeled neurons were found in the caudal part of the bilateral fastigial nucleus following injection 1, and anterograde labeled axon terminals were observed in the bilateral suprageniculate nucleus following injection 2. Electron microscopic observations of these terminals revealed that they were large terminals making asymmetric synaptic contacts with dendrites. These results suggest that some neurons in the fastigial nucleus send their axons to the suprageniculate nucleus.

Animals↗
PubMed1976

Effects of colchicine and vinblastine on axonal transport of choline acetyltransferase in rat sciatic nerve.

The effects of colchicine (0.5-10(-2) M) and vinblastine (10(-2)-10(-5) M) Upon axonal transport of choline acetyltranserase (CAT) and on nerve impulse conduction have been investigated in the rat sciatic nerve. High concentrations of colchicine (0.5 M) and vinblastine (10(-2) M) blocked completely both axonal transport of CAT and impulse conduction. 10(-3) M vinblastine did not affect impulse conduction until 20-22 h after injection, but this concentration of vinblastine did block CAT transport but not impulse conduction. 10(-2) M and 10(-1) M colchicine were without effect on impulse conduction, but did produce substantial, although incomplete, block of CAT transport. The results are discussed in relation to the possible involvement of microtubules in transport of CAT.

Acetyltransferases↗
PubMed2004

Cyclin-dependent kinase 5 increases perikaryal neurofilament phosphorylation and inhibits neurofilament axonal transport in response to oxidative stress.

Cyclin-dependent kinase 5 (cdk5) phosphorylates the high molecular weight neurofilament (NF) protein. Overexpression of cdk5 inhibits NF axonal transport and induces perikaryal accumulation of disordered phospho-NF cables. Experimental and clinical motor neuron disease is characterized by oxidative stress, increased cdk5 activity, and accumulation of phospho-NFs within perikarya or proximal axons. Because oxidative stress increases cdk5 activity in experimental motor neuron disease, we examined whether oxidative stress induced cdk5-mediated NF phosphorylation. Treatment of cultured neuronal cells with hydrogen peroxide inhibited axonal transport of green fluorescent protein-tagged NF subunits and induced perikaryal accumulation of NF phosphoepitopes normally confined to axons. These effects were prevented by treatment with the cdk5 inhibitor roscovitine or transfection with a construct expressing the endogenous cdk5 inhibitor peptide. These findings indicate that oxidative stress can compromise NF dynamics via hyperactivation of cdk5 and suggest that antioxidants may alleviate multiple aspects of neuropathology in motor neuron disease.

Animals↗
PubMed1987

Fast axonal transport of acetylcholinesterase in rat sciatic motoneurons is enhanced following prolonged daily running, but not following swimming.

The effects of increases in neuronal activity on fast axonal transport of acetylcholinesterase (AChE) in sciatic motoneurons were studied by subjecting rats to daily running or swimming training (8 weeks). Net accumulation of AChE activity proximal and distal to a ligature served to evaluate orthograde and retrograde transport. Results showed that runners had greater orthograde and retrograde transport of AChE as compared to control animals, while no changes were found in swimmers. These adaptations in the runners were caused by the long-term nature of the training regimen since an acute exercise session had no effect on AChE transport. The observed changes may be attributed to an increase in the mobile fraction of AChE in the motoneurons. Since swimming training had no effect on transport but entails a high level of neuronal activity, it is suggested that increased impulse activity is not the factor mediating the adaptations in axonal transport of AChE which resulted from running training.

Acetylcholinesterase↗
PubMed1980

Axonal transport in rats rendered paraplegic following a single subarachnoid injection of either batrachotoxin or 6-aminonicotinamide into the spinal cord.

Batrachotoxin (BTX) or 6-aminonicotinamide (6-AN) when injected into the subarachnoidal space of the lumbar spinal cord block fast axonal transport of 3H-protein in motor nerves. Axonal transport recovers partially within one day after administering BTX while the effect of 6-AN lasts for more than 21 days. These observations are discussed in relation to the onset and recovery of membrane depolarization observed in the extensor muscle.

6-Aminonicotinamide↗
PubMed1980

Retrograde axonal transport of target tissue-derived macromolecules.

Neurones depend on contact with their target tissues for survival and subsequent development. The protein, nerve growth factor (NGF), can be selectively taken up by sympathetic nerve terminals and reaches the neuronal perikaryon by a process of retrograde intra-axonal transport, suggesting that its role in vivo is to act as a target tissue-derived trophic factor. The development of the neurones of the chick ciliary ganglion requires the presence of structures derived from the optic cup. Several studies in vitro have shown that media conditioned by non-neuronal cells contain factors that result in the survival of neurones from ciliary ganglia. In particular, chick embryo iris, ciliary body and choroid contained large amounts of these factors indicating the presence of a target tissue-derived trophic factor for the cholinergic ciliary ganglion. This study demonstrates that neurones of the ciliary ganglion accumulate, by retrograde intra-axonal transport, proteins synthesized and released by optic tissues in culture.

Animals↗
PubMedDate not supplied

Protein loss from axonal transport occurs without diminution of vesicle traffic.

Protein loss from the rapid anterograde axonal transport system of amphibian sensory nerve fibers was compared with the numbers and sizes of anterogradely transported vesicles in the axons. Protein was found to be lost at a rate of approximately 2% per millimeter of nerve traversed. However, no changes were observed in either the numbers or sizes of vesicles in the nerve at two locations separated by 60-75 mm. The results show that protein loss is not explained as a loss of vesicles from the transport system nor by a reduction in vesicle size.

Animals↗
PubMed1981

Fodrin: axonally transported polypeptides associated with the internal periphery of many cells.

Fodrin (formerly designated 26 and 27) comprises two polypeptides (250,000 and 240,000 mol wt) that are axonally transported at a maximum time-averaged velocity of 40 mm/d--slower than the most rapidly moving axonally transported proteins, but faster than at least three additional groups of proteins. In this communication, we report the intracellular distribution of fodrin. Fodrin was purified from guinea pig brain, and a specific antifodrin antibody was produced in rabbit and used to localize fodrin in tissue sections and cultured cells by means of indirect immunofluorescence. Fodrin antigens were highly concentrated in the cortical cytoplasm of neurons and also nonneuronal tissues (e.g., skeletal muscle, uterus, intestinal epithelium). Their disposition resembles a lining of the cell: hence, the designation fodrin (from Greek fodros, lining). In cultured fibroblasts, immunofluorescently labeled fodrin antigens were arranged in parallel arrays of bands in the plane of the plasma membrane, possibly reflecting an exclusion of labeled fodrin from some areas occupied by stress fibers. The distribution of fodrin antigens in mouse 3T3 cells transformed with simian virus 40 was more diffuse, indicating that the disposition of fodrin is responsive to altered physiological states of the cell. When mixtures of fodrin and F-actin were centrifuged, fodrin cosedimented with the actin, indicating that these proteins interact in vitro. We conclude that fodrin is a specific component of the cortical cytoplasm of many cells and consider the possibilities: (a) that fodrin may be indirectly attached to the plasma membrane via cortical actin filaments; (b) that fodrin may be mobile within the cortical cytoplasm and that, in axons, a cortical lining may be in constant motion relative to the internal cytoplasm; and (c) that fodrin could serve to link other proteins and organelles to a submembrane force-generating system.

Actins↗
PubMed1985

Axonal transport of alpha-bungarotoxin binding sites in rat sciatic nerve.

[125I]alpha-Bungarotoxin (alpha-BuTX) binding sites accumulate both proximal and distal to a ligature positioned around the sciatic nerve of rats. [125I]alpha-BuTX binding sites, localized using quantitative receptor autoradiography, were found to accumulate at nerve ligatures at a relatively constant rate which suggests that they undergo both anterograde and retrograde axonal transport. [125I]alpha-BuTX binding to sections of ligated sciatic nerve was saturable with apparent dissociation constants of 0.97 nM proximal and 0.53 nM distal to the ligature. D-Tubocurarine, nicotine, decamethonium and atropine displaced [125]alpha-BuTX from sciatic nerve sections with affinities comparable to those previously reported for the toxin binding component of rat brain. These data indicate that [125I]alpha-BuTX binding sites pharmacologically similar to those of rat brain are transported in sciatic nerve. Axonally transported toxin binding sites may correspond to those previously localized to the plasma membrane of peripheral nerve axons and on the terminals of motor neurons.

Animals↗
PubMed2006

Axonal transports of tripeptidyl peptidase II in rat sciatic nerves.

Axonal transport of tripeptidyl peptidase II, a putative cholecystokinin inactivating serine peptidase, was examined in the proximal, middle, and distal segments of rat sciatic nerves using a double ligation technique. Enzyme activity significantly increased not only in the proximal segment but also in the distal segment 12-72h after ligation, and the maximal enzyme activity was found in the proximal and distal segments at 72h. Western blot analysis of tripeptidyl peptidase II showed that its immunoreactivities in the proximal and distal segments were 3.1- and 1.7-fold higher than that in the middle segment. The immunohistochemical analysis of the segments also showed an increase in immunoreactive tripeptidyl peptidase II level in the proximal and distal segments in comparison with that in the middle segment, indicating that tripeptidyl peptidase II is transported by anterograde and retrograde axonal flow. The results suggest that tripeptidyl peptidase II may be involved in the metabolism of neuropeptides in nerve terminals or synaptic clefts.

Aminopeptidases↗
PubMed1989

Protein changes during anterograde-to-retrograde conversion of axonally transported vesicles.

In the axon tip, cell biological mechanisms convert anterogradely transported membranous elements. To study the effects of these anterograde-to-retrograde (A-R) converting mechanisms on the electrophoretic behaviour of vesicle proteins, we compared the proteins of anterograde vesicles (before A-R conversion at the axon tip) with those of retrograde vesicles (after A-R conversion at the axon tip). The proteins in transported vesicles were pulse-labeled with [35S]methionine, and the radiolabeled vesicles were concentrated by ligating the axons-anterograde vesicles accumulate selectively on the proximal side of the ligature and retrograde vesicles accumulate on the distal side of the ligature. Analyses of vesicle proteins by polyacrylamide gel electrophoresis (SDS-PAGE) show that most of the anterograde proteins were also present in the retrograde vesicles. In addition to the conservation of these anterograde proteins in the retrograde vesicles, there were also many differences: some anterograde proteins were diminished in the retrograde vesicles, other anterograde proteins were absent from the retrograde vesicles, and the retrograde vesicles contained some new protein bands that were not present in the anterograde vesicles. These results indicate that A-R converting mechanisms modify membranous vesicle proteins in the axon tip. We propose that some of these post-translational protein modifications change the directional code on the vesicle surfaces, thereby converting anterograde membranous elements into retrograde membranous elements.

Animals↗
PubMed1985

Proteins in fast axonal transport are differentially transported in branches of sensory nerves.

Radioactively labeled, fast-transported proteins were collected at ligatures placed on peripheral and central branches of spinal sensory nerves of the bullfrog. In agreement with previous studies, we found that the same species of proteins were transported down each branch. For each protein species analyzed we have measured the amount of radioactivity reaching each ligature, and calculated the ratio of radioactivity reaching the peripheral ligature to that reaching the central ligature. Not all protein species have the same ratio. This suggests that there may be differential transport of fast-transported proteins in axonal branches.

Animals↗
PubMed1985

Uptake and anterograde axonal transport of Aleuria lectin in retinal ganglion cells of the rabbit.

A fucose-specific lectin from Aleuria aurantia was used to study the dynamics of neuronal membrane glycoproteins. Albino rabbits received vitreal injections of affinity-purified 125I-Aleuria lectin. The radioactive probe was internalized by adsorptive endocytosis into retinal ganglion cells, and transported intact down to the nerve terminals in the contralateral geniculate bodies and superior colliculi. We found that the radiolabeled lectin was transported with at least two distinct rates (I, approximately 205 mm/day; II, approximately 45 mm/day) corresponding to the two rapid phases of anterograde transport of endogenous polypeptides described earlier in this system. This is the first evidence that an exogenous macromolecule may be transported along the axon at more than one velocity.

Animals↗
PubMed1982

Electron microscopic study of retrograde axonal transport of horseradish peroxidase in the wall of the small intestine in the cat.

The intracellular distribution of horseradish peroxidase (HRP) transported intra-axonally from the mesenteric nerve to the wall of the small intestine has been examined electron microscopically. After 2 days, some of the neurons of the myenteric and submucosal plexuses showed an accumulation of HRP. The HRP reaction product consisted of fine, discrete cytoplasmic granules and it was located in lysosome-like dense bodies with a 400-500 nm of diameter. The morphological features of the labelled neurons, with synapses occurring on their surfaces, were apparently different from those of unlabelled neurons. Some nerve fibers were also labelled and could be found in all layers of the small intestine. The labelled neurons project directly towards the celiac ganglia, and due to the synapses on their surfaces, it is supposed that these neurons collect information from other local nerve cells and centripetally convey them to the prevertebral ganglia.

Animals↗
PubMed1997

Axonal transport blockade in the neonatal rat optic nerve induces limited retinal ganglion cell death.

Optic nerve section in the newborn rat results in a rapid apoptotic degeneration of most axotomized retinal ganglion cells (RGCs). This massive process of neuronal death has been ascribed mainly to the interruption of a trophic factor supply from target structures rather than to the axonal damage per se. To distinguish between these two possibilities, we induced a reversible axonal transport blockade in the developing optic nerve by topical application of a local anesthetic (lidocaine). Light and electron microscopy showed no alterations in the fine structure of treated optic nerves. Retinae of treated and control rats were stained with cresyl violet and examined at different times after surgery. We found that axonal transport blockade induced only a limited number of pyknotic RGCs. Degeneration of these cells was completely prevented by inhibiting protein synthesis during lidocaine application. We conclude that the rapid degeneration of RGCs after axotomy can be ascribed only partly to the loss of retrogradely transported trophic factors.

Anesthetics, Local↗
PubMed1987

Defects of axonal transport in experimental diabetes that are unrelated to the sorbitol pathway.

This study examined the effect of experimental diabetes on the anterograde and retrograde axonal transport of phosphofructokinase activity. Rats with streptozotocin-induced diabetes of 4 weeks duration showed phosphofructokinase activity accumulation deficits both proximal (53% and 65% in two separate experiments) and distal (80% and 70%) to 24-h sciatic nerve constrictions. There was no significant effect of diabetes on the phosphofructokinase activity per unit length in unconstricted sciatic nerve. Treatment of a group of diabetic rats with the aldose reductase inhibitor, sorbinil, profoundly reduced the concentrations of polyol pathway metabolites (sorbitol and fructose) in sciatic nerve. This effective inhibition of aldose reductase did not alter the accumulation deficits of phosphofructokinase activity on either side of sciatic nerve constrictions. We conclude that short-term experimental diabetes causes impaired axonal transport of phosphofructokinase activity by mechanisms unrelated to aldose reductase.

Aldehyde Reductase↗