Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A quantitative electron microscopic (EM) study combining the anterograde intra-axonal transport of radioactive amino acids and the retrograde intra-axonal transport of the enzyme horseradish peroxidase (HRP) was performed in the magnocellular red nucleus of the rat to obtain anatomical evidence as to whether there is a direct projection from the cerebellar nucleus interpositus to the cells in the red nucleus that give rise to the rubrospinal tract. Large asymmetrical synaptic terminals were radioactively labeled in the magnocellular red nucleus following injections of [3H]leucine into the cerebellar nucleus interpositus. In these same animals, the postsynaptic target neurons were labeled with HRP granules after injection of this substance in the rubrospinal tract. A quantitative analysis showed that more than 85% of the large and giant neurons in the magnocellular red nucleus were labeled with HRP granules and also received synaptic contacts from radioactively-labeled terminals. Thus, it can be concluded that in the rat, afferents from the cerebellar nucleus interpositus establish asymmetrical synaptic contacts with large and giant rubrospinal neurons, thus confirming and extending the previous physiological evidence of such direct monosynaptic connections.
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PMID:Anatomical evidence for direct fiber projections from the cerebellar nucleus interpositus to rubrospinal neurons. A quantitative EM study in the rat combining anterograde and retrograde intra-axonal tracing methods. 616 12

Myelinated axons were isolated from the sciatic nerve of Xenopus laevis and were subjected to localized (less than 30 microns wide) lesions. In axons which were bathed in a 0.12 M potassium glutamate solution there was very little local reaction to the lesion and optically-detectable particles undergoing axoplasmic transport accumulated immediately adjacent to, and mostly distal to, the lesion. Preparations fixed for electron microscopy at times up to 3 h following the lesion showed that the axoplasmic changes about the lesion were asymmetrical. Large organelles predominated on the distal side of the lesion; these were mostly dense lamellar bodies (DLB) with mean dimensions, as determined from thin sections, of 0.48 by 0.19 microns. Multivesicular bodies, mitochondria, and a variety of smaller membrane bounded bodies also appeared in the particle accumulation distal to the lesion. Analysis of these results led to the conclusion that DLB were transported up to the lesion and represent the majority of the optically detectable particles which are transported in the retrograde direction. Small vesicles and tubules were the commonest structures which accumulated proximal to the lesion. The time course of this accumulation was consistent with the hypothesis that these structures are particulate bodies which move in the orthograde direction at about 1.5 microns/s. Incidental findings which are also of significance to the study of axonal transport were: large particulate material may reverse its direction of movement at an axonal obstruction, and organelles which accumulate on either side of a lesion do so in rows which are associated with microtubules.
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PMID:The short term accumulation of axonally transported organelles in the region of localized lesions of single myelinated axons. 616 22

Following symmetrical bilateral infusion of D-glucose into the basal ventromedial hypothalamus (BVMH), using Alzet minipumps (1 microliter/h of 10% D-glucose for 6 days), average daily food intake was reduced by 27% for the period of treatment. Symmetrical bilateral infusions into the posterior medial hypothalamus had a transitory effect on feeding, as did asymmetrical and unilateral infusions. Infusion of L-glucose into the BVMH did not yield a chronic reduction in food intake. Included in the infused solutions were tracer amounts of [14C]glucose, [14C]proline or [14C]leucine to permit radioautographic estimations of infusate dispersal in the brain and axonal transport patterns from the infusion sites. Infusions were generally well-restricted to 1-1.5 mm of the cannulae tips, and descending transport of amino acids was highest in substantia nigra and midline structures of the mesencephalon and pons including central gray, ventral tegmental area, raphe and ventral tegmental nuclei. These results provide evidence for an energy intake regulatory mechanism situated in the BVMH whose outputs may modulate activity in the substantia nigra and midline brain stem areas.
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PMID:D-glucose infusions into the basal ventromedial hypothalamus and feeding. 617 Dec 96

In acute electrophysiological experiments on anaesthetized cats, single identified hair follicle afferent fibres were injected with horseradish peroxidase (HRP). The HRP was injected from an intra-axonal microelectrode in the lumbosacral spinal cord. One to six hours after injection the animals were perfused and the tissue prepared for light and electron microscopy (EM). Axon collateral arborizations containing HRP reaction product were identified in thick sections under the light microscope and the same tissue then cut on the ultramicrotome for EM study. The terminal branches of the collaterals kept their myelin sheaths until they were 0.45-1.0 micron in diameter, just before they formed synaptic boutons. Synaptic boutons (1.0-4.0 microns in diameter) were usually of the en passant variety and made contact with dendrites. The contacts were asymmetrical (Type I) and contained round, clear synaptic vesicles of 35-60 nm diameter. Both the non-myelinated portion of the terminal axon and the synaptic boutons received axo-axonic contacts. These axo-axonic boutons contained clear (agranular) vesicles irregular in profile.
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PMID:Ultrastructure of hair follicle afferent fibre terminations in the spinal cord of the cat. 618 75

The level of endogenous nerve growth factor (NGF) in rat sciatic nerve was determined using a highly sensitive two-site enzyme immunoassay. After crushing this nerve NGF accumulated linearly distal to the crush during the first 12 h to reach levels 13-fold higher than in the uncrushed contralateral side. In contrast, proximal to the crush NGF levels approached or were below the detection limit of the assay. The asymmetrical distribution of NGF on the two sides of a crush is direct evidence for the retrograde axonal transport of endogenous NGF.
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PMID:Quantitative demonstration of the retrograde axonal transport of endogenous nerve growth factor. 619 60

Area 18 of V II of the prestriate cortex of the squirrel monkey was examined at both the light and electron microscopic (EM) levels for cytochrome oxidase (C.O.) activity. At the 17/18 border, the intense C.O. staining of lamina 4 abruptly ended and a new pattern continued for approximately 6 mm into the adjacent prestriate cortex. Here, periodic puffs of high C.O. activity appeared in laminae (lam.) 2 and 3, with the highest activity in lower 3 (3B) extending slightly into upper 4. There was a hint of a columnar pattern in that lam. 4 and especially 5 below the puffs were slightly more reactive than adjacent areas. A thin band of activity could also be seen in upper 5 (5A) and another one between 5 and 6. Tangential sections revealed that the puffs were arranged in alternating wide and narrow rows that radiated orthogonally from the 17/18 border. The puffs in the wider rows tended to be larger (700-1,100 micrometers in diameter) than those in the narrow rows (400-890 micrometers in diameter). The center-to- center spacing between the puffs was approximately 1,100 micrometers. Both C.O.-reactive and nonreactive stellate and pyramidal cells were found between lam. 2 and 6. Quantitatively analysis of the supragranular layers indicated that the mean area of reactive neurons was significantly larger than that of nonreactive neurons in both the puffs and interpuff (nonpuff) regions. The relative density of reactive neurons was also significantly greater than that of nonreactive neurons, and was highest within the puffs. At the EM level, reactive neurons were medium to large pyramidal cells as well as medium-sized stellates with mild to severely indented nuclei and darker cytoplasm filled with reactive mitochondria. The majority of small stellates with scanty cytoplasm and few mitochondria were nonreactive. Extensive quantitative analysis of mitochondria number and level of reactivity in different neuronal profiles indicated that the number and area of darkly reactive mitochondria was significantly higher in the puffs than in the nonpuffs, and that the majority of them resided in dentritic profiles. Between a third to half of the mitochondria in axonal profiles were darkly reactive, the frequency being slightly higher in profiles with flattened vesicles making symmetrical synapses than those with round vesicles making asymmetrical synapses. Mitochondria in axonal trunks and myelinated axons contributed to only a small percentage of the total population. Glial cells, in general, were not very reactive.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Quantitative light and electron microscopic analysis of cytochrome oxidase-rich zones in V II prestriate cortex of the squirrel monkey. 632 63

The retrograde horseradish peroxidase technique was used to: (1) identify and assess the overall morphology of large neurons in the ventrolateral portion (VL) of rat trigeminal nucleus oralis projecting to cervical, thoracic and lumbosacral levels of the spinal cord; and (2) characterize the synaptic endings terminating on their dendrites. The morphology of large VL neurons projecting to all spinal levels is similar. They have 25-50 microns pyramidal-shaped somata which emit 3-6 primary dendrites. These primary dendrites give rise to spherical to elliptical-shaped dendritic arbors measuring up to 700 microns in diameter. Labeled axons enter either a deep axon bundle or the medial portion of the spinal V tract. Dendrites of labeled neurons are contacted by axonal endings of 3 types. The most numerous endings are filled with clear, spherical synaptic vesicles and usually form single asymmetrical contacts along the entire length of dendritic shafts. Synapsing less frequently on dendritic shafts are endings containing pleomorphic synaptic vesicles and forming single symmetrical synaptic contacts. The least frequently encountered synaptic terminal contains flattened synaptic vesicles and makes a single symmetrical synaptic contact with a dendritic shaft.
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PMID:Axonal endings terminating on dendrites of identified large trigeminospinal projection neurons in rat trigeminal nucleus oralis. 652 24

Pyramidal, aspinous, sparsely-spinous bipolar and multipolar neurons of the rat sensomotor cerebral cortex, impregnated after Golgi method, have been studied at an electron microscopical level. The ultrastructural characteristics of the pyramidal neurons differs from that of the nonpyramidal cells. Distribution of various synaptic contacts on the cellular surface and cortical postsynaptic targets of the axonal arborizations of the neurons are revealed. On the body of the pyramidal cells only symmetrical synapses exist, on large dendritic trunks symmetrical synapses prevail, on the spines and the terminal dendritic branches assymetrical synapses mainly predominate. Axonal collateralies of the pyramidal cells form asymmetrical synapses on the spines, small and middle dendrites. There are more axo-somatic synapses on the bodies of the nonpyramidal neurons than on the pyramidal cells, among them both symmetrical and asymmetrical types of the synapses occur. On the trunks and small dendrites of the nonpyramidal cells both types of synaptic contacts are revealed. In the distal direction of the dendrites the number of the asymmetrical synapses becomes predominating. Axons of the bipolar cells form asymmetrical synapses on the spines, small and middle dendrites. Axons of the multipolar cells form symmetrical synapses on the dendrites and the dendritic trunks of the nondifferentiated cells. Differences in the distribution character of the synaptic inlets and various postsynaptic targets of the axonal systems in the cells assume various functional role of the identified neurons.
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PMID:[Morphological characteristics of various segments of local connections in the rat somatosensory cortex]. 666 Oct 45

The anterograde horseradish peroxidase (HRP) technique was used to identify ascending intratrigeminal axons originating from neurons in the medullary dorsal horn (MDH) which terminate in trigeminal nucleus oralis (Vo). HRP injections into the MDH labeled two populations of axons ascending ipsilaterally within the spinal trigeminal nucleus. The first population was composed of parent branches which each gave off a single branching collateral strand to Vo as they ascended. These collaterals were characterized by boutons filled with small, round synaptic vesicles and forming asymmetrical synaptic contacts with large diameter dendritic shafts. The second axonal population was made up of parent branches which terminated directly in Vo. Their short terminal strands were distinguished by axonal endings containing pleomorphic synaptic vesicles and forming symmetrical synaptic junctions with small diameter dendritic shafts and spines.
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PMID:Termination in trigeminal nucleus oralis of ascending intratrigeminal axons originating from neurons in the medullary dorsal horn: an HRP study in the rat employing light and electron microscopy. 669 29

The electrophysiological features in 145 patients with a new toxic syndrome related to ingestion of adulterated oil are described. Myalgia, joint limitation, weight loss, cramps, progressive weakness and wasting, sensory disturbances that can be asymmetrical or patchy, and scleroderma-like changes were the main clinical features. The electrophysiological findings suggest that the neuromuscular impairment in the new toxic syndrome is a slowly progressive mixed axonal neuropathy, which starts asymmetrically in some patients, with involvement of proximal and distal muscles as well as paraspinal and respiratory muscles. Muscle and nerve biopsies confirm the neuropathy, and show severe perineuritis and perineurial and perimysial fibrosis. The single fiber electromyography (SFEMG) study showed increased motor unit fiber density directly related to the time after onset of the illness. Unstable complex potentials were found after 6 months of evolution, which suggests that an effective collateral reinnervation was delayed following a long period of progressive denervation.
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PMID:Neuromuscular disorders in a new toxic syndrome: electrophysiological study--a preliminary report. 670 Jun 25


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