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

Cholecystokinin (CCK)-8-like immunoreactive structures in the nucleus of tractus solitarius (NTS) were studied by using the peroxidase-antiperoxidase (PAP) immunohistochemical method. Immunoreactivity was localized in cell bodies and nerve fibers. The perikarya were oval or fusiform (average length 13 micron) and were mostly located in the dorsal half of the medial subnucleus of the NTS at the level of the area postrema (AP). One to three straight immunoreactive dendritelike processes emerged from the perikarya. Neurons that had first been identified under light microscopy were also studied by electron microscopy. Each neuron had a moderate amount of cytoplasm and an oval or elongated nucleus that was eccentrically located in the soma. A few synaptic inputs were found on the CCK immunoreactive perikarya, while a moderate number were seen on both proximal and distal dendrites. These neurons received both asymmetrical and symmetrical synaptic inputs. The immunoreactive dendrites were most frequently in asymmetrical synaptic contact with nonreactive boutons (max. 2.7 micron in diameter) containing fairly densely packed, small round vesicles. CCK immunoreactive boutons located in the NTS at the level of the AP were analyzed using electron microscopy; these boutons formed asymmetrical synaptic contact with other neuronal elements. Their postsynaptic targets were immunoreactive and nonreactive perikarya and dendrites. These data suggest that CCK-containing afferents might affect the neurotransmission of heterogenous types of solitary neurons.
 ...
PMID:Fine structural studies of cholecystokinin-8-like immunoreactive neurons and axon terminals in the nucleus of tractus solitarius of the rat. 609 May 10

Somatostatin-immunoreactive neurons in the rat neostriatum were studied by correlated light and electron microscopy using the peroxidase-antiperoxidase immunocytochemical technique. Immunoreactivity was localized in neuronal perikarya and processes. The perikarya were of spindle or fusiform shape (average length 16.9 microns) and were found in all parts of the neostriatum. From each neuron there arose two to four straight immunoreactive dendritelike processes, which could frequently be traced as far as about 130 microns from their perikaryon. Immunoreactive varicose axonlike processes were occasionally found, some of which were proximal axons of identified immunoreactive cells. Nine of the light microscopically identified neurons showing somatostatin-immunoreactivity were studied in the electron microscope; two of them had proximal axons with varicosities. Each neuron had an oval or elongated nucleus, which was always indented. These morphological features correspond well to those of certain "medium-size aspiny" neurons classified by Golgi studies. Although the immunoreactive endproduct was diffusely located throughout the neuron, it was characteristically located in the saccules and large granules (diameter 133 nm) of the Golgi apparatus, and large immunoreactive vesicles of similar size to those in the Golgi apparatus frequently occurred in all parts of axon. Very little synaptic input was found on the perikarya and dendrites of somatostatin-immunoreactive neurons. The perikarya and proximal dendrites received both symmetrical and asymmetrical synaptic input, while the distal dendrites usually received boutons that formed asymmetrical contacts. The somatostatin-immunoreactive boutons contained pleomorphic electron-lucent vesicles (diameter 39.3 nm) and a few large immunoreactive granular vesicles; these boutons always formed symmetrical synapses. Their postsynaptic targets were dendritic shafts, spines, and unclassified dendritic profiles. On the other hand, the varicosities of identified proximal axons of somatostatin-positive neurons did not form typical synapses, since they lacked clusters of small vesicles, but some of them were in direct apposition (via membrane specializations) to unlabelled perikarya or dendrites. It is concluded that somatostatin is a useful marker for a particular type of neuron in the neostriatum. The presence of somatostatin immunoreactivity in synaptic boutons is consistent with the view that somatostatin could be a neurotransmitter in the neostriatum.
 ...
PMID:Fine structural studies on a type of somatostatin-immunoreactive neuron and its synaptic connections in the rat neostriatum: a correlated light and electron microscopic study. 613 37

The cellular distribution of guanylate cyclase (EC 4.6.1.2), guanosine 3',5'-phosphate (cyclic GMP), cyclic GMP-dependent protein kinase (EC 2.7.1.38), and cyclic GMP phosphodiesterase (EC 3.1.4.17) have been examined in the rostral rat caudate-putamen complex. Immunofluorescent staining for guanylate cyclase, cyclic GMP, and cyclic GMP-dependent protein kinase in fresh frozen caudate-putamen tissues is analogous to the immunoperoxidase localization in perfusion-fixed striatal slices. Homologous immunoreactivity in the cytoplasm and processes of ovoid and rounded neurons, 15-20 microns in diameter can be seen for these three components of the cyclic GMP system. Immunoreactive neurons are uniformly distributed throughout the caudate-putamen complex of all experimental tissue examined. Occasional large neurons, greater than 25 microns in diameter, in the ventral region of the striatum show immunoreactivity. Enzyme histochemical determination of the activities of guanylate cyclase and cyclic GMP phosphodiesterase show the medium-sized neuronal population (15-20 microns) contain hydrolytic activity for these proteins. Large- to medium-sized capillaries demonstrate guanylate cyclase synthetic activity, but the endothelial cells do not exhibit immunohistochemical staining. This suggests that physiological activity of an enzyme cannot be completely discerned through application of immunohistochemical procedures. Additionally, enzymatically detected guanylate cyclase histochemical activity was not uniformly distributed throughout the striatal neuropil. Enzyme histochemical detection of cyclic GMP phosphodiesterase demonstrates homologous cellular staining to guanylate cyclase enzymatic reactivity. The activity of the phosphodiesterase hydrolytic enzyme could be detected evenly distributed throughout the neuropil within cells 15-20 microns in diameter, analogous in cytoarchitecture to immunohistochemically visualized guanylate cyclase, cyclic GMP, and protein kinase elements. Ultrastructural examination of rat caudate-putamen demonstrates that the immunoreactivity for the components of the cyclic GMP system is predominantly distributed within the medium-spiny neuron subtype of this structure. Occasional aspiny neurons demonstrate peroxidase immunoreactivity for the cyclase, cyclic GMP, and the protein kinase, as does the luminal surface of capillary endothelial cells. The subcellular distribution of the antigenic determinants for these three elements and the hydrolytic activity of the phosphodiesterase enzyme show proximity to one another and are confined to the postsynaptic region of asymmetrical, but not symmetrical, terminal boutons. The asymmetrical terminal population of the caudate-putamen is derived from striatal afferents from the neocortex, intralaminar thalamus, and substantia nigra, and to a lesser extent the intrinsic striatal circuitry.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Distribution of components of the guanosine 3',5'-phosphate system in rat caudate-putamen. 613 69

Tyrosine hydroxylase-immunoreactive fibres in the rat neostriatum were studied in the electron microscope in order to determine the nature of the contacts they make with other neural elements. The larger varicose parts of such fibres contained relatively few vesicles and rarely displayed synaptic membrane specializations; however, thinner parts of axons (0.1-0.4 micron) contained many vesicles and had symmetrical membrane specializations, indicative of en passant type synapses. By far the most common postsynaptic targets of tyrosine hydroxylase-immunoreactive boutons were dendritic spines and shafts, although neuronal cell bodies and axon initial segments also received such input. Six striatonigral neurons in the ventral striatum were identified by retrograde labelling with horseradish peroxidase and their dendritic processes were revealed by Golgi impregnation using the section-Golgi procedure. The same sections were also developed to reveal tyrosine hydroxylase immunoreactivity and so we were able to study immunoreactive boutons in contact with the Golgi-impregnated striatonigral neurons. Each of the 280 immunoreactive boutons examined in the electron microscope displayed symmetrical synaptic membrane specializations: 59% of the boutons were in synaptic contact with the dendritic spines, 35% with the dendritic shafts and 6% with the cell bodies of striatonigral neurons. The dendritic spines of striatonigral neurons that received input from immunoreactive boutons invariably also received input, usually more distally, from unstained boutons that formed asymmetrical synaptic specializations. A study of 87 spines along the dendrites of an identified striatonigral neuron showed that the most common type of synaptic input was from an individual unstained bouton making asymmetrical synaptic contact (53%), while 39% of the spines received one asymmetrical synapse and one symmetrical immunoreactive synapse. It is proposed that the spatial distribution of presumed dopaminergic terminals in synaptic contact with different parts of striatonigral neurons has important functional implications. Those synapses on the cell body and proximal dendritic shafts might mediate a relatively non-selective inhibition. In contrast, the major dopaminergic input that occurs on the necks of dendritic spines is likely to be highly selective since it could prevent the excitatory input to the same spines from reaching the dendritic shaft. One of the main functions of dopamine released from nigrostriatal fibres might thus be to alter the pattern of firing of striatal output neurons by regulating their input.
 ...
PMID:Tyrosine hydroxylase-immunoreactive boutons in synaptic contact with identified striatonigral neurons, with particular reference to dendritic spines. 615 36

Following the injection of horseradish peroxidase into the ipsilateral substantia nigra, 36 retrogradely labelled neurons in the striatum were characterized (in three rats) by Golgi staining and gold toning: each neuron was of the medium-size, densely spinous type. Prior to the injection of horseradish peroxidase, two of the rats had had lesions placed in the ipsilateral motor cortex, the third rat had had a lesion placed in the ipsilateral frontal and prefrontal cortex. In the electron microscope, degenerating boutons of cortical neurons were found in asymmetrical synaptic contact with the spines of proximal and distal dendrites of all six of the identified striatonigral neurons that were studied. Some of the degenerating boutons were small (diameter 0.1-0.3 micron), while others were larger (1-2 microns). An individual dendrite of a striatonigral neuron was in symaptic contact with very few degenerating boutons. Local axon collaterals in the striatum could be traced from two of the identified striatonigral neurons that received degenerating cortical boutons. These were studied in the electron microscope; their boutons formed symmetrical synapses with spines or dendritic shafts of other striatal neurons. The synaptic boutons contained large, clear, round and pleomorphic vesicles. The postsynaptic targets of these boutons morphologically resemble the dendrites of medium-size spiny neurons. It is concluded that afferents from the cortex make monosynaptic contact with the dendritic spines of medium-size spiny striatonigral neurons and that such neurons have local axon collaterals in the striatum that form synapses with other spiny neurons.
 ...
PMID:Monosynaptic cortical input and local axon collaterals of identified striatonigral neurons. A light and electron microscopic study using the Golgi-peroxidase transport-degeneration procedure. 616 49

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.
 ...
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

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.
 ...
PMID:Ultrastructure of visual callosal neurons in cat identified by retrograde axonal transport of horseradish peroxidase. 617 21

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.
 ...
PMID:Ultrastructure of hair follicle afferent fibre terminations in the spinal cord of the cat. 618 75

The main neuronal systems containing substance P are summarized on the basis of immunohistochemical evidence. The substance P striatonigral projection is one of the most conspicuous of these. Electron microscopic studies using the peroxidase-antiperoxidase technique reveal some heterogeneity in the substance P-immunostained material in the substantia nigra. Immunoreactivity for the peptide is found in terminals establishing both symmetrical and asymmetrical synapses with substantia nigra dendrites. Substance P immunoreactivity in the substantia gelatinosa of the trigeminal nerve and in the skin of the trigeminal territory was found to be depleted after sensory denervation. Electron microscopy showed that in this area of the rat brain substance P-immunoreactive elements are largely associated with dendrites and establish asymmetrical axo-dendritic synapses. Substance P-immunoreactive terminals synapsing with presynaptic dendrites were also observed (i.e. dendrites that themselves are presynaptic to other dendrites). The origin of substance P-containing fibres in the prevertebral ganglia has been investigated in the guinea-pig by combining surgical procedures and immunohistochemistry. Only procedures which disconnected dorsal root ganglia from prevertebral ganglia depleted substance P immunofluorescence in the latter. This substance P-immunoreactive material disappeared after administration of capsaicin. Electron microscopic studies in prevertebral ganglia show that substance P-immunoreactive varicosities establish axodendritic contacts with the sympathetic neurons. These observations provide strong evidence for direct synaptic sensory-autonomic interactions in the prevertebral ganglia involving substance P-containing collaterals of peripheral sensory nerve fibres.
 ...
PMID:Localization of substance P in neuronal pathways. 618 80

The ultrastructural localization of substance P-like immunoreactivity (SPLI) in lamina I (marginal zone) and lamina IIO (outer substantia gelatinosa) of the dorsal horn of the macaque monkey was examined by the indirect antibody peroxidase-antiperoxidase method. SPLI was found in small unmyelinated and finely myelinated axons and a variety of terminal types. The majority of SPLI terminals contained a few to many large granular vesicles (mean diameter 90 nm) in addition to a population of small clear round vesicles. A very few terminals contained mainly small round vesicles. SPLI terminals were presynaptic in axosomatic, axodendritic and axospinous contacts forming, in all but the axosomatic junctions, asymmetrical synapses. Some axosomatic junctions were symmetrical. SPLI terminals also formed the center of glomeruli with unlabeled dendrites and dendritic spines; some of the unlabeled dendrites contained a few small scattered vesicles and large dense-core vesicles. In more complex formations 2 to 4 SPLI terminals were associated with one another and linked by desmosomal contacts. The individual terminals in the complexes or 'congregate terminals' were simple large granular vesicle containing terminals (LGV), LGV-central terminals of associated glomeruli, or terminals containing mainly small round vesicles. In the apical region of lamina I an unlabeled terminal was found occasionally in contact with an SPLI terminal, which in turn synapsed onto a dendrite. These contacts have some synaptic characteristics and the SPLI terminal was possibly postsynaptic. Most of the types of SPLI terminals resemble closely terminal types shown to be of primary afferent origin. These terminals which make direct contact with dorsal horn dendrites may be the morphological substrate for postsynaptic excitation of dorsal horn neurons by substance P. The contacts of unlabeled terminals with SPLI terminals may represent a morphological substrate by which other neurochemical substances such as enkephalin or serotonin may modulate the substance P effects on dorsal horn neuronal activity.
 ...
PMID:Ultrastructure of chemically defined neuron systems in the dorsal horn of the monkey. I. Substance P immunoreactivity. 619 42


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>