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PubMed1995

Vanilloid (capsaicin) receptors in the rat: distribution in the brain, regional differences in the spinal cord, axonal transport to the periphery, and depletion by systemic vanilloid treatment.

Vanilloid (capsaicin) receptors were visualized by [3H]resiniferatoxin (RTX) autoradiography in the brain of newborn as well as adult (both control and colchicine-treated) rats. Specific labelling was seen in the brain stem only, in the nucleus of the solitary tract extending into the area postrema and the spinal sensory nucleus of the trigeminal nerve. Also, a strong signal was seen in the dorsal horn, dorsal root, trigeminal and nodose ganglia. Membranes obtained from the cervical, thoracic, and lumbar segments of the spinal cord showed similar affinities for RTX and likewise for capsaicin and capsazepine; maximal receptor density was similar in the cervical and thoracic segments (approximately 70 fmol/mg protein) but was twice as high in the lumbar segment. 24 h after ligation of the vagal or the sciatic nerves, a strong accumulation of specific RTX binding sites was observed mainly proximal to the ligature, implying intraaxonal receptor transport from the nodose and dorsal root ganglia, respectively, to the periphery. Systemic (s.c.) vanilloid treatment depleted specific [3H]RTX binding sites from the brain stem, the sensory (dorsal root as well as trigeminal) ganglia, and the spinal cord. RTX was approximately 200-fold more potent than capsaicin for eliminating vanilloid receptors from the spinal cord. The present results suggest a discrete expression of vanilloid receptors in the brain stem (sensory nuclei); although intrinsic vanilloid receptor-expressing neurons are though to exist in the rat brain, they remain undetected by the present [3H]RTX autoradiography methodology.

Animals↗
PubMed1985

The efferent projections from the reticular formation and the locus coeruleus studied by anterograde and retrograde axonal transport in the rat.

Following injections of [3H]leucine into the formatio reticularis gigantocellularis (Rgc), reticularis pontis caudalis (Rpc), reticularis pontis oralis (Rpo), reticularis mesencephali (Rmes), or the locus coeruleus (LC) of the rat, autoradiographic study revealed prominent reticuloreticular projections from all areas and secondary projections onto cranial nerve motor nuclei from most areas within the brain stem. Common long descending projections extended the full length of the spinal cord terminating in the ventromedial ventral horn and intermediate zone and more sparsely in the base of the dorsal horn and (particularly from Rgc) the region of the motoneurons. Common long ascending projections extended into the forebrain via Forel's tegmental fascicles. A dorsal branch of fibers innervated the intralaminar and midline nuclei of the thalamus. The major fiber system continued forward through Forel's fields and ascended into the pallidum from Rpo, Rmes, and LC and into the neostriatum from Rmes and LC. Fascicles from all areas also ascended in the medial forebrain bundle through the lateral hypothalamus to the lateral preoptic area, substantia innominata, and nuclei of the diagonal band. From Rpo, Rmes, and LC, fibers continued forward to reach the cerebral cortex, where the innervation was sparse and discrete from Rpo and Rmes but moderate and ubiquitous from LC. Retrograde transport of true blue and/or nuclear yellow revealed inverse gradients along the brain stem longitudinal axis of interdigitated cells respectively projecting caudally into the spinal cord (with the greatest number of cells in Rgc, Rpc, and Rpo) and rostrally into the diencephalon (with the greatest number of cells in Rmes and LC), with very few cells projecting both to the spinal cord and the diencephalon. From the basal forebrain, a large number of reticular and LC cells were retrogradely labelled, whereas from the frontal cortex, a much smaller number of reticular cells was labelled. These results document the widespread efferent projections from the reticular formation and overlapping, yet more extensive, projections from the LC.

Amidines↗
PubMed1977

The identification of two intra-axonally transported polypeptides resembling myosin in some respects in the rabbit visual system.

Two polypeptides (M1 and M2) which co-sediment with F-actin in an ATP-reversible way have been detected in extracts of tissue from the rabbit visual system. Both polypeptides resemble skeletal muscle myosin in their ATP-sensitive co-sedimentation with actin, while they resemble the heavy chain of myosin and the lighter polypeptide of erythrocyte spectrin in their electrophoretic mobilities. (The estimated molecular weights are: MI congruent to 195,000; myosin congruent 200,000; M2 and spectrin congruent to 220,000). M1 and M2 were labeled in the cell bodies of the retinal ganglion cells with a radioactive amino acid and subsequently recovered in tissues (optic nerve, optic tract, lateral geniculate nucleus, and superior colliculus) containing segments of the retinal ganglion cell axons. The temporal sequence of labeling M1 and M2 in these tissues indicated that both polypeptides were synthesized in the cell bodies of retinal ganglion cells and subsequently transported down their axons at different maximum velocities. The estimated velocities were: M1, 4-8 mm per day; and M2, 2-4 mm per day.

Animals↗
PubMed1981

Axonal transport of the mitochondria-specific lipid, diphosphatidylglycerol, in the rat visual system.

Rats 24 d old were injected intraocularly with [2-3H]glycerol and [35S]methionine and killed 1 h-60 d later. 35S label in protein and 3H label in total phospholipid and a mitochondria-specific lipid, diphosphatidylglycerol(DPG), were determined in optic pathway structures (retinas, optic nerves, optic tracts, lateral geniculate bodies, and superior colliculi). Incorporation of label into retinal protein and phospholipid was nearly maximal 1 h postinjection, after which the label appeared in successive optic pathway structures. Based on the time difference between the arrival of label in the optic tract and superior colliculus, it was calculated that protein and phospholipid were transported at a rate of about 400 mm/d, and DPG at about half this rate. Transported labeled phospholipid and DPG, which initially comprised 3-5% of the lipid label, continued to accumulate in the visual structures for 6-8 d postinjection. The distribution of transported material among the optic pathway structures as a function of time differed markedly for different labeled macromolecules. Rapidly transported proteins distributed preferentially to the nerve endings (superior colliculus and lateral geniculate). Total phospholipid quickly established a pattern of comparable labeling of axon (optic nerve and tract) and nerve endings. In contrast, the distribution of transported labeled DPG gradually shifted toward the nerve ending and stabilized by 2-4 d. A model is proposed in which apparent "transport" of mitochondria is actually the result of random bidirectional saltatory movements of individual mitochondria which equilibrate them among cell body, axon, and nerve ending pools.

Animals↗
PubMed1981

Ultrastructure of visual callosal neurons in cat identified by retrograde axonal transport of horseradish peroxidase.

The ultrastructure of neurons at the border of areas 17 and 18 of the visual cortex of the cat was studied by the combined use of the retrograde transport of horseradish peroxidase (HRP) and electron microscopy. Callosal neurons were retrogradely labelled by injecting HRP at the 17/18 border region of the contralateral hemisphere. They were found mainly in layer III but also in IV and VI. They were most commonly pyramidal cells and less often large, spiny stellate cells. Pyramidal callosal neurons received only symmetrical synapses on their soma and mainly symmetrical (but a few asymmetrical) synapses on their dendritic shafts. Their abundant spines received asymmetrical synapses. The stellate cells were contacted by moderate numbers of symmetrical and asymmetrical axodendritic and axosomatic synapses and also had asymmetrical axospinous contacts. We propose that the callosal stellate neurons consist of a class of large spiny stellates, recognizable by light and electron microscopic criteria.

Animals↗
PubMed1980

Axonal transport of dopamine-beta-hydroxylase to rat salivary glands: studies on enzymatic activity.

The method by Nagatsu and Udenfriend (1972) to measure dopamine-beta-hydroxylase (DBH) activity was applied for tissue samples. Proximal to a crush or a ligature of the perihilar tissue of the rat salivary glands, DBH activity was found to increase about linearly with time. However, more DBH activity accumulated after ligation than after crushing. Noradrenaline (NA) accumulated also after a ligature but the increase appeared to exceed a linear one. The same pattern for the increase in NA we earlier had observed proximal to a crush of the rat sciatic nerve. It was now found that the accumulation of DBH activity was about linear with time in the crushed sciatic nerve, without any signs of supra-normal increase. The same increase was found after a crush as after a ligature. The ratio of accumulating NA and DBH activity agreed in the two neuronal systems.

Animals↗
PubMed1986

Labeling of cutaneous sensory nerve endings with axonally transported horseradish peroxidase and wheat germ agglutinin-horseradish peroxidase conjugate: a methodological study in the rat.

Practical aspects on the use of horseradish peroxidase (HRP) and wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) to trace peripheral cutaneous nerve endings have been studied. The parameters studied included application site of the tracer, post-application survival time, tracer concentration and tracer volume. These parameters were examined in the glabrous skin of the rat hindpaw. The best results were obtained with injections of 1 microliter WGA-HRP (20 micrograms/microliter) in dorsal root ganglia innervating the examined cutaneous region and a postinjection survival time of 18-36 h. With this approach extensive and heavy labeling was achieved of epidermal nerve endings, nerve endings in Merkel cell-neurite complexes and Meissner corpuscles. Useful, but less extensive labeling of these types of peripheral nerve endings, was obtained with injections of HRP in the lumbar spinal cord dorsal horn.

Animals↗
PubMed2000

Anterograde axonal transport of glial cell line-derived neurotrophic factor and its receptors in rat hypoglossal nerve.

Glial cell line-derived neurotrophic factor is one of the most potent motoneuron survival factors yet identified. Although retrograde transport of trophic factors to the cell body is thought to be an important process in motoneuron survival, the transport pathways that lead to interaction of glial cell line-derived neurotrophic factor with its receptors is not known. We have used a double ligated hypoglossal nerve preparation to investigate transport of endogenous glial cell line-derived neurotrophic factor and its receptors, glial cell line-derived neurotrophic factor family receptor alpha1 and receptor re-arranged during transfection. Glial cell line-derived neurotrophic factor was found to accumulate at the distal ligature, indicating retrograde transport and consistent with its motoneuron survival effects. In addition, we observed accumulation of glial cell line-derived neurotrophic factor and its receptors at the proximal ligature, indicating anterograde transport. This finding is not predicted by neurotrophic theory. Staining for glial cell line-derived neurotrophic factor in the motor axons was punctate, suggesting involvement of transport vesicles. Results obtained using immunohistochemistry and reverse transcription-polymerase chain reaction provide evidence for the synthesis of glial cell line-derived neurotrophic factor and glial cell line-derived neurotrophic factor family receptor alpha1 in Schwann cells and glial cell line-derived neurotrophic factor family receptor alpha1 and receptor re-arranged during transfection in motoneuron cell bodies. When the motor axons were separated from the cell body by avulsion, glial cell line-derived neurotrophic factor remained in the vicinity of the Schwann cells and did not accumulate at the proximal ligature. Our results indicate anterograde transport of Schwann cell-derived glial cell line-derived neurotrophic factor, which is dependent on binding to its cell body-derived receptors. These findings suggest a mechanism for collection of glial cell line-derived neurotrophic factor from multiple Schwann cells which surround motor axons. We propose that in addition to its role in motoneuron survival, glial cell line-derived neurotrophic factor may also modulate local neuronal effects in distal regions of the nerve.

Animals↗
PubMed1985

[Effect of blockade of axonal transport on endplate currents of muscle fibers in the frog].

The evoked and spontaneous end-plate currents (EPC) were measured in normal voltage-clamped frog sartorius muscle fibres and after colchicine blockade of axoplasmic transport in the corresponding nerve. Colchicine application decreased the growth rate and increased the decay time constant of EPC without changes in the average amplitude of EPC and miniature EPC, quantum content of EPC and frequency of miniature EPC. The increase in EPC time constant was combined with an increase in the sensitivity of the time constant to holding potential, but there were no changes in the amplitude of EPC as a function of holding potential in the reversal potential of EPC. It is suggested that the increase in the EPC decay time constant was due to the appearance of a new population of receptor--ion channel complexes with opening time similar to that described for extrajunctional receptors after denervation. The neurotrophic control of chemosensitive muscle fibre membrane depended on the axoplasmic flow.

Animals↗
PubMed1975

Isolation of axonally transported glycoproteins with goldfish visual system myelin.

[3H]fucose labeled glycoproteins which are rapidly transported in the goldfish optic nerve have been isolated with purified preparations of goldfish optic tectal myelin. SDS acrylamide gels of myelin proteins isolated one day after intraocular injection of fucose show a broad distribution of radioactivity among high molecular weight proteins. At progressively longer times after injection there is a shift in the distribution of radioactivity with the buildup of a peak of label with electrophoretic mobility corresponding to a molecular weight of approximately 50,000. There is no corresponding peak of radioactivity in gels of total tectal membranes. Gels of myelin labeled through intracranial injections of fucose also show no single prominent peak of radioactivity. Results are discussed with reference to possible mechanisms for the shift in radioactivity patterns on gels and the possible functional significance of the myelin-associated glycoproteins.

Animals↗
PubMed1978

A difference between the proteins conveyed in the fast component of axonal transport in guinea pig hypoglossal and vagus motor neurons.

We compared the proteins transported in the fast component of guinea pig hypoglossal motor neurons with those of guinea pig vagus (preganglionic parasympathetic) neurons. The fast component proteins of hypoglossal and vagus neurons were radioactively labeled by injecting 3H-amino acids into the hypoglossal and vagus motor nuclei. The radioactive fast component proteins obtained from each system were then compared with each other by SDS-polyacrylamide slab gel electrophoresis and fluorography. These analyses revealed at least twenty polypeptides which appear common to the fast component of each neuronal system. In addition, we identified one difference between the proteins comprising the fast component of these neuronal systems. A polypeptide, molecular weight 50,000 daltons, present in the fast component of vagus neurons was not detected in the fast component of hypoglossal motor neurons. These observations are discussed with regard to the similarities and differences between these neuronal systems.

Animals↗
PubMed1978

[Study of the neurons of the supraspinal systems of the cat brain using the method of retrograde axonal transport of horseradish peroxidase].

Horseradish peroxidase (HRP) was injected into cervical, thoracic, lumbar and sacral segments of 18 cats. In all the cases HRP was transported retrogradely to the brain stem neurons in the medial reticular formation, vestibular complex and the red nucleus. The present findings demonstrate that, in addition to the above mentioned groups, there exist several other groups of neurons. Many labelled neurons are present in the locus coeruleus and the nucleus subcoeruleus, ipsilaterally. These neurons seem to be located in the same position as the monoaminergic (catecholamine-containing) neurons. Labelled HPR-positive neurons are present in the retroambiguous nucleus and in the upper pontine tegmentum adjoining the rubrospinal tract, mainly contralaterally, in the bulbar raphe, the mesencephalic central gray and the hypothalamus, mainly ipsilaterally. The occurrence of retrograde-labelled neurons in the locus coeruleus and the dorsal hypothalamus after HRP injections as far caudally as the lumbar segments, indicates that these cell groups give rise to descending fibres which pass almost the entire length of the spinal cord.

Animals↗
PubMed1979

Afferent and efferent connections of the parabigeminal nucleus in cat revealed by retrograde axonal transport of horseradish peroxidase.

Afferent and efferent connections of the parabigeminal nucleus (PBG) of the cat have been demonstrated by means of horseradish peroxidase (HRP) tracing technique. Following HRP injection in the PBG, labelled cells were observed mainly in the deep layers of the ipsilateral superior colliculus (SC). The other labelled structures were the prepositus hypoglossi complex (PH), the ventral nucleus of the lateral geniculate body (LGV), the locus coeruleus, the cuneiform nucleus, the periaqueductal gray and the dorsomedial hypothalamic area. Efferent projections of the PBG were investigated by HRP injection in SC, LGV, PH, hypothalamus and in some acoustic relays, i.e. medial geniculate body and inferior colliculus. Only the PBG-SC projection appeared to be well systematized. The positive labelling of the PBG following injection of LGV and hypothalamus is discussed in terms of the specificity of the injection. The absence of afferent and efferent connections of the PGB with any acoustic relay tends to exclude this nucleus from the auditory system in contrast to previous suggestions. On the basis of the close reciprocal PBG-SC connections a possible role of the PBG within visuomotor tectal function is proposed.

Afferent Pathways↗
PubMed2002

Effect on motor neuron survival in mutant SOD1 (G93A) transgenic mice by Bcl-2 expression using retrograde axonal transport of adenoviral vectors.

We investigated the effect of exogenous Bcl-2 on motor neurons in transgenic mice expressing human Cu/Zn superoxide dismutase with a G93A mutation (G93A mice), using adenoviral vectors with a cassette for Bcl-2 (AxCALNLBcl-2) and Cre recombinase (AxCANCre) to express Bcl-2 by Cre-loxP recombination. We were able to detect Bcl-2 in the hypoglossal nuclei of G93A mice for at least 8 weeks after inoculation with AxCALNLBcl-2 followed by inoculation with AxCANCre into the tongue of 10-week-old G93A mice. We examined the morphological changes of motor neurons in the hypoglossal nuclei of each mouse at 25 weeks of age, at which time the G93A mice manifested signs of neural degeneration. We found that the number of motor neurons was significantly higher in the G93A mice with both vectors than in those with AxCALNLBcl-2 alone or without inoculation. Further, we observed an obvious reduction of vacuole formations and reactive astrocytes in and around the hypoglossal nuclei of G93A mice with both vectors. These results suggest that expression of Bcl-2 introduced by our system has a protective effect on degeneration of motor neurons in G93A mice.

Adenoviridae↗
PubMed1986

Selective interruption of axonal transport of neurofilament proteins in the visual system by beta,beta'-iminodipropionitrile (IDPN) intoxication.

Beta,beta'-iminodipropionitrile (IDPN) is an agent that produces a marked impairment in the transport of neurofilaments. Its effect on other slowly transported cytoskeletal components such as tubulin and actin is variable. Previous studies have evaluated transport of neurofilaments after IDPN intoxication in a neurofilament-rich system (sciatic motor nerves) and in a system devoid of neurofilaments (axons of the dorsal motor nucleus of the vagus). In the former, IDPN impairs the transport of tubulin and actin but to a lesser degree than it does neurofilament proteins. In the latter, tubulin and actin transport were not impaired, and neurofilament proteins were not present. In this study we evaluated the transport of the cytoskeletal components in a system with an intermediate amount of neurofilaments (the visual system). In the visual system, there is a selective and marked (50%) impairment in the transport of neurofilaments with no impairment in transport of tubulin or microtubule-associated proteins (tau group). We conclude that these different patterns of impairment in transport reflect the differences in pre-intoxication neurofilament content of the nerves examined, the effect of IDPN on the transport of the other components of slow transport being secondary to the presence of stagnated neurofilaments. This model also suggests that transport of neurofilaments can be selectively impaired without producing an effect on other major slow transport components.

Animals↗
PubMed1977

The pontine projection to the flocculonodular lobe and the paraflocculus studied by means of retrograde axonal transport of horseradish peroxidase in the rabbit.

The occurrence and distribution of labeled cells in the pontine nuclei were mapped following injections of small amounts of horseradish peroxidase (0.05-0.5 microliter, 50% suspension) in the flocculus, nodulus and the dorsal and ventral paraflocculus in adult albino rabbits. While no labeled cells were found in the pontine nuclei following injections in the nodulus, some were present following injections in the flocculus and a great number following injections in the paraflocculus. The projections onto the flocculus and paraflocculus are precisely organized. Following injections in the paraflocculus labeled neurons are arranged in four columns (E and G in the paramedian pontine nucleus, F in the peduncular and H in the dorsolateral nucleus). Following injections in the ventral paraflocculus labeled cells are present only in parts of column E and F, while columns G and H and parts of E and F project onto the dorsal paraflocculus. Following injections in the flocculus labeled cells occur in the rostral part of column E only. A comparison between the sites of termination of pontine afferents and the areas giving origin to floccular and parafloccular fibers shows that only few fibers mediating visual impulses end in these pontine areas, while they receive numerous fibers from gyrus cinguli and areas 18 and 19 of the cerebral cortex.

Animals↗
PubMed1977

The olivocerebellar projection studied with the method of retrograde axonal transport of horseradish peroxidase. V. The projections to the flocculonodular lobe and the paraflocculus in the rabbit.

HRP was injected in the flocculonodular lobe and the paraflocculus in the rabbit to determine the areas of the inferior olive which project onto these cerebellar regions. Following injections in the flocculus labeled cells occurred in the dorsal cap and the rostralmost tip of the medial accessory olive. Following injections in the nodulus labeled cells were likewise found in the dorsal cap, but in addition in the rostralmost part of the dorsomedial cell column and the adjoining part of the medial accessory olive. Injections in the dorsal paraflocculus gave rise to labeling in the rostrolateral part of the medial accessory olive, while injections in the ventral paraflocculus resulted in labeling in the principal olive, mainly in the lateral part of the ventral lamella. Injections in the lateral third of the dentate nucleus gave rise to labeling mainly in the dorsal lamella of the principal olive. The results are discussed with reference to those obtained by previous authors. There are both similarities and discrepancies. It appears from what is known of afferents from areas mediating visual impulses to the inferior olive that the olivary areas projecting onto the flocculonodular lobe, and possibly the dorsal paraflocculus, may mediate visual impulses to these lobules.

Afferent Pathways↗
PubMed1992

Presynaptic terminal loss from alpha-motoneurones following the retrograde axonal transport of diphtheria toxin.

Intercostal motoneurones intoxicated following intraneural injection of diphtheria toxin exhibited a progressive dilatation and fragmentation of Nissl body rough endoplasmic reticulum (rER), coupled with two different forms of presynaptic terminal response. Firstly, terminal dysjunction without prior degeneration, and secondly, Wallerian-type degeneration. Dysjunction was attributed to a toxin-related failure by the motoneurones to maintain postsynaptic site structure. Degeneration was considered to arise from toxicity in presynaptic neurones, either neighbouring motoneurones or local interneurones. Morphometry revealed that by 8 days, intoxicated motoneurones exhibited a 33% loss in terminal frequency, a 15% loss in residual presynaptic membrane, and a 43% loss in overall presynaptic input. The concomitant loss of synaptic sites was greater that the overall loss of presynaptic membrane, indicating a toxin-related deficiency of the maintenance of postsynaptic sites. Analyses of the relationship between changes in terminal numbers and the development of Nissl body abnormality in the postsynaptic motoneurone identified three groups of motoneurones: (i) those with normal presynaptic input and normal neuronal Nissl body rER; (ii) those showing a dramatic loss of presynaptic input and a marked dilatation and fragmentation of Nissl bodies; and (iii) neurones exhibiting a maintained or further loss of presynaptic input coupled with extreme dilatation and fragmentation of Nissl body rER with loss of Nissl body structure. These changes are discussed in context with the known molecular action of diphtheria toxin.

Animals↗