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Query: UNIPROT:P50583 (
asymmetrical
)
12,197
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The synaptic interactions between terminals of allocorticostriatal and thalamostriatal fibers and the cholinergic neurons in the nucleus accumbens were investigated using degeneration and dual labelling immunocytochemistry in Wistar rats. The presumptive cholinergic neurons were labelled with antibodies directed against choline acetyltransferase and the afferent fibers were labelled anterogradely with Phaseolus vulgaris-leucoagglutinin. Fibers from the subiculum of the hippocampal formation and from the midline and intralaminar thalamus project densely into the medial nucleus accumbens where they overlap a relatively dense population of choline acetyltransferase-immunoreactive neurons.
Varicosities
containing Phaseolus vulgaris-leucoagglutinin juxtapose the immunoreactive neurons. To study the possibility that the cholinergic neurons could be the synaptic targets of these incoming fibers, the subiculum, the fornix, and the midline/intralaminar thalamus were lesioned in separate animals and brain sections were immunoprocessed for choline acetyltransferase and studied with the electron microscope. In addition, dual-labelling electron microscopic immunocytochemistry was employed. In total, 164 synaptic terminals from the subiculum/hippocampus and 130 from the midline/intralaminar thalamus were examined; all formed
asymmetrical
synaptic specializations. No hippocampal endings were seen to contact the somata or primary dendrites of the choline acetyltransferase-immunoreactive neurons; however, three were found in synaptic contact with distal, immunolabelled dendritic shafts. Most hippocampal terminals established contacts with unlabelled spines. Fifteen percent of the thalamic endings were found to synapse on the somata and the primary and distal dendrites of the choline acetyltransferase-immunoreactive neurons. The remaining thalamic terminals established synaptic junctions with small unlabelled dendrites or spines. These findings have important implications not only for our understanding of the synaptic organization of the hippocampal and thalamic projections to the nucleus accumbens, but also for the contribution of the cholinergic neurons to the circuitry of this nucleus.
...
PMID:Hippocampal and midline thalamic fibers and terminals in relation to the choline acetyltransferase-immunoreactive neurons in nucleus accumbens of the rat: a light and electron microscopic study. 235 32
Cellular relationships between serotonin (5-HT) axon terminals and neurons containing vasoactive intestinal peptide (VIP) were characterized by combined radioautography and immunocytochemistry in rat suprachiasmatic nucleus (SCN). Light microscopic immunoradioautographs showed significant overlap between (3H)5-HT uptake sites and VIP-immunoreactive elements in the ventral half of the SCN. Of the 255 (3H)5-HT-labelled axonal profiles detected in a systematic electron microscopic survey of single thin sections from this area, 75 (30%) were directly apposed to VIP-immunoreactive nerve cell bodies and/or dendrites. Radioautographically labelled 5-HT
varicosities
often showed well-differentiated, symmetrical or
asymmetrical
synaptic junctions, 60% of which were established on VIP-immunoreactive nerve cell bodies or dendrites. In a separate sampling of 198(3H)5-HT-labelled terminals seen in apposition with VIP-immunoreactive elements, 50 showed a junctional complex at the site of contact. Postsynaptic immunoreactive elements were mostly dendrites but also included nerve cell bodies. Despite the methodological limitations inherent to the present double labelling approach, these data strongly support the view that VIP neurons are prime synaptic targets for 5-HT afferents in the SCN. VIP/5-HT interactions are thus likely to play an important functional role in this nucleus and may in particular subserve the 5-HT mediated regulation of certain circadian rhythms, including that of pituitary hormone secretion.
...
PMID:VIP neurons as prime synaptic targets for serotonin afferents in rat suprachiasmatic nucleus: a combined radioautographic and immunocytochemical study. 241 20
In the present study, we examined the ultrastructure of striatal neurons containing neuropeptide Y (NPY) which were labeled by an immunohistochemical method using peroxidase-conjugated F(ab) fragments in the rat. Each of the 26 neurons identified had a deeply indented oval nucleus. The cytoplasm, which was mainly concentrated at the emergence of the dendrites, contained an abundant Golgi apparatus and a well-developed granular endoplasmic reticulum. Dendrites were poorly branched and rarely exhibited
varicosities
or dendritic spines. NPY-immunoreactive (Ir) axons were small in diameter and unmyelinated. These features corresponded to a subpopulation of striatal neurons classified as aspiny type IV in previous Golgi studies. Axon terminals forming symmetrical synapses were numerous on the NPY-Ir perikarya and proximal dendrites. On distal NPY-Ir dendrites, synaptic contacts were mainly of the
asymmetrical
type, suggesting that NPY neurons are contacted by at least 2 categories of afferent fibers. Several NPY-Ir axonal processes and boutons were found to form symmetrical synapses with dendrites, dendritic spines and perikarya belonging to spiny type neurons. These data were consistent with the view that NPY may act as a neurotransmitter of striatal interneurons. Moreover, the frequent observation of NPY axonal processes in the close vicinity of striatal vessels suggested that NPY might also play a role in the control of cerebral vasomotricity. Thirty hours after intranigral injection of 6-hydroxydopamine to induce a degeneration of nigrostriatal dopamine terminals, some characteristic degenerative boutons were observed in close apposition to NPY-Ir cell bodies, suggesting that NPY neurons are under a direct nigrostriatal dopaminergic influence.
...
PMID:Ultrastructural features of NPY-containing neurons in the rat striatum. 270 86
High-resolution radioautography after cerebroventricular administration of tritiated serotonin (5-HT) and PAP immunocytochemistry with an antiserum against 5-HT-glutaraldehyde conjugate (kindly donated by M. Geffard) were used in parallel to investigate the intrinsic and relational fine structural features of 5-HT axon
varicosities
(terminals) in the neostriatum of the adult rat. The uptake-labeled
varicosities
were examined in single thin sections from a paraventricular sector of neostriatum, whereas their immunostained counterparts were viewed in serial thin sections from the same paraventricular sector plus a dorsal neostriatal sector. The two approaches yielded complementary results in terms of varicosity dimensions, synaptic features and appositional relationships. Serotonin axon terminals were generally small and, as measured in immunostained material, even smaller in the dorsal than in the paraventricular neostriatum. Their internal features, best viewed in radioautographs, included small pleomorphic synaptic vesicles with occasional large granular vesicles and mitochondria. Junctional 5-HT terminals from both the paraventricular and the dorsal neostriatal sectors synapsed exclusively, and with equal frequency, on dendritic spines or shafts, almost always with
asymmetrical
membrane differentiations. The proportion of junctional
varicosities
, however, was very low in serial (immunocytochemical) as well as single (radioautographic) thin sections. Only 10-13% of 5-HT
varicosities
from either the paraventricular or the dorsal neostriatum exhibited a synaptic junction, in contrast with a junctional incidence of at least 70% for randomly selected axonal
varicosities
similarly sampled in the surrounding neuropil. Serotonin axon terminals, whether or not synaptic, were closely apposed to a variety of structures comprising mostly other axon terminals, dendritic spines and branches, but rarely neuronal somata. The synaptic and appositional features of immunostained 5-HT
varicosities
were similar for both the dorsal and the paraventricular neostriatum. In this context, it is likely that the effects of 5-HT in the neostriatum are exerted upon a multiplicity of cellular target sites in addition to the restricted number of dendritic spines and shafts synaptically contacted by this type of monoamine terminal.
...
PMID:Serotonin innervation in adult rat neostriatum. II. Ultrastructural features: a radioautographic and immunocytochemical study. 270 68
The dopaminergic innervation of the rat primary (area 17) and secondary (areas 18 and 18a) visual cortical areas was examined immunocytochemically using an antiserum directed against dopamine. This innervation was characterized by the differential density of the respective afferents within individual visual areas. Area 18, especially its rostral part, was observed to receive a considerable amount of dopaminergic axons, whereas areas 17 and 18a were sparsely innervated. The innervation of all layers of area 18 seemed to consist to a considerable extent of axonal branches of radial fibres ascending from layer VI to layer I. At the ultrastructural level, dopamine profiles were found to display similar characteristics in all visual areas. Dopamine labelled axon-terminals and axonal
varicosities
, examined in single and serial ultrathin sections, were seen to form primarily
asymmetrical
synaptic contacts with dendritic profiles. These observations suggest a 'specific' innervation of cytoarchitectonically distinct cortical regions by dopaminergic axons.
...
PMID:Light and electron microscopic immunocytochemical analysis of the dopamine innervation of the rat visual cortex. 274 3
PAP immunocytochemistry with an antiserum against serotonin (5-HT)-glutaraldehyde-protein conjugate (kindly donated by M. Geffard) was used to analyze the ultrastructural relationships of 5-HT axon terminals (
varicosities
) in the frontal (Fr1-Fr2), parietal (Par1), and occipital (Oc1M-Oc2) cortex of adult rats. One hundred-forty-five immunostained
varicosities
from Fr1-Fr2 (54 from layers I-II; 91 from layer VI) and 97 each from the upper layers (I-II) of Par1 and OcM1-Oc2 were examined in groups of serial thin sections (mean number of sections in series: 3.2 to 7.3). These terminals were of comparable shape and size in the 4 cortical sectors examined, and averaged 0.66 +/- 0.2 microns in mean diameter. The proportion of
varicosities
engaged in synaptic contact was evaluated by linear transformation of the relationship between the frequency of observed synaptic junctions and the number of thin sections available for examination. Reliability of the sampling was evidenced by a high coefficient of correlation (r greater than 0.95) in each cortical sector. The synaptic incidence extrapolated for whole
varicosities
ranged from 28% (layer VI of Fr1-Fr2) to 46% (Par1), without statistically significant differences between the 4 sectors examined. The interregional mean could thus be evaluated at 38%. The synaptic 5-HT terminals always made
asymmetrical
junctions, which were exclusively found on dendritic spines and shafts, and appeared more frequent on spines than shafts in the deep frontal and the upper occipital cortex. In all 4 sectors, dendritic shafts and spines and other axonal
varicosities
were frequently encountered in the immediate microenvironment of the immunostained
varicosities
. It is concluded that the cortical 5-HT innervation is predominantly nonjunctional throughout the neocortex of the adult rat, which reinforces earlier views of a highly divergent afferent system with particular functional properties and perhaps capable of widespread, global and/or sustained influences in this part of the brain.
...
PMID:Ultrastructural relationships of serotonin axon terminals in the cerebral cortex of the adult rat. 280 57
Tyrosine-hydroxylase (TH-IR) and methionine-enkephalin like immunoreactivity (MetE-IR) were analyzed in the lateral septal nucleus (LSN) of the rat from birth (PO) to adulthood. TH-IR labeled specifically the dopaminergic (DA) pericellular arrangements of the LSN, as checked by negative dopamine-beta-hydroxylase and phenylethanolamine-N-methyl transferase-IR. TH-IR and Met-IR processes were present at birth in the medial LSN and extended lateralwards and caudalwards from P0 to P6 to constitute two main DA terminal fields (medial and lateral) surrounding a MetE one. Within these fields, the development of perineuronal baskets followed a similar medial to lateral sequence: DA axons first surrounded a few neuronal cell bodies at P3 in the medial part of the intermediate LSN; at P6, Met-IR axons encircled more laterally located perikarya, and only at P9, some neurons located along the ventricle in the lateral DA field became surrounded. The initial aspect of TH-IR baskets consisting of few axons surrounding the cell body rapidly evolved in a positive network encapsulating the perikaryon and long segments of the proximal dendrites, whereas MetE-IR
varicosities
remained restricted around the perikaryon and the initial dendritic segments. Ultrastructural study at P14 revealed numerous TH-IR and MetE-IR axosomatic and axodendritic profiles. TH-IR axosomatic
varicosities
exhibited
asymmetrical
synapses, whereas MetE-IR ones displayed rare symmetrical contacts. The medio-lateral gradient of development of the perineuronal baskets was parallel to the postnatal neuronal development of the LSN as evaluated by cytological criteria: neuronal density, cell size and Nissl staining. Therefore, the formation of DA and MetE perineuronal arrangements in the LSN does not seem to be subordinate to the nature of the neurotransmitter they contain but related to the level of differentiation of their target neurons. A similar sequential set-up in the development of afferences paralleling the neuronal differentiation is discussed.
...
PMID:Postnatal sequential development of dopaminergic and enkephalinergic perineuronal formations in the lateral septal nucleus of the rat correlated with local neuronal maturation. 289 20
Using antibodies raised against gamma-aminobutyric acid (GABA)-glutaraldehyde complexes, we have found neurons with GABA-like immunoreactivity in the superior cervical ganglion of adult rats. The processes of these neurons formed pericellular networks around the principal ganglion cells. Electron microscopy revealed that the immunoreactive dendrites were innervated by non-reactive axon terminals which formed
asymmetrical
synapses and probably originated from the preganglionic nerve. Axons with GABA-like immunoreactivity, especially axonal
varicosities
filled with synaptic vesicles, were found in direct apposition to principal ganglion cells. The GABA-positive axons and axon
varicosities
persisted in experimentally decentralized (deafferented) ganglia, suggesting that the perikarya of the immunoreactive neurons were intrinsic to the superior cervical ganglion. Taken together with data on inhibitory effects of GABA in sympathetic ganglia, these findings suggest that the superior cervical ganglion of rats contains a subpopulation of inhibitory interneurons which is GABAergic. This would indicate that GABAergic neurons do not only occur in the central but also in the peripheral nervous system.
...
PMID:Presence of neurons with GABA-like immunoreactivity in the superior cervical ganglion of the rat. 302 73
Cutis marmorata telangiectatica congenita (CMTC) is characterized by a persistent vascular mottling of the skin, usually on the limbs. Four cases (2 males and 2 females) followed up for varying lengths of time are reported. In the first patient, whose vascular lesions were mild, careful re-examination after 10 years revealed some scars. In the second patient the lesions were located on the right side of the body, notably on the leg; 6 years later atrophic scars and a brownish plaque were visible on that leg. In the third patient the lesions occupied almost the entire body, although one side was more affected than the other and hypotrophic; the child's face was
asymmetrical
because of hypoplasia of the jaw and curvature of the nose; after 1 year the patient's general condition was satisfactory and the skin lesions were less evident but still present. In the fourth patient hypoplasia of a lumbar vertebra was discovered; the skin lesions were similar to those observed in the third patient. Examination of the deep vessels, performed whenever possible, did not show any abnormality, but the possibility of future vascular defects, such as
varicosities
, must be considered. While some authors emphasize the functional character of the disease, in our opinion the high frequency of multiple associated congenital abnormalities makes CMTC not only a vascular disorder but also a syndrome including other neuroectodermal and mesodermal defects. Therefore, any patient presenting with the cutaneous changes typical of CMTC should be examined with this in mind.
...
PMID:[Cutis marmorata telangiectatica congenita. 4 new cases and review of the literature]. 332 46
The distribution of GABA-immunoreactive neurons and axonal
varicosities
was investigated in the hippocampal region of the rat brain by means of an indirect peroxidase immunocytochemical method with recently developed anti-GABA antibodies. The immunolabeling was found to be restricted to nervous structures: neuronal cell bodies, dendrites and axon terminals. Myelinated axons showing GABA-immunoreactivity were also observed. GABA-immunoreactive neurons were found in great number in the stratum pyramidale, the superficial part of the stratum oriens and the deep part of the stratum radiatum in the Ammon's horn. Less were found in the other regions; rare labeled cells were observed in the superficial part of the stratum radiatum and the middle part of the stratum oriens. The dentate gyrus exhibited numerous labeled cells in the granular layer, few in the hilus, rare in the molecular layer. A high density of GABA-immunoreactive terminals was found at the limit of the stratum oriens with the alveus, in the stratum pyramidale and in the stratum lacunosum. A lower density of labeled fibers was observed in the other areas. The somata and proximal dendrites of pyramidal and granular cells were encompassed by characteristic pericellular arrangements of GABA-immunoreactive
varicosities
. Ultrastructural observations revealed a diffuse immunoreaction product spread over the cytoplasm and the nucleus without specific relationship with the organelles, and immunoreactive aggregates in the cytoplasm. Labeled dendrites often showed enlargements displaying the immunoreaction whereas thinner segments were devoid of it. They received numerous
asymmetrical
synapses from unlabeled axon terminals. GABA-immunoreactive terminals were filled with small clear vesicles with immunopositive membranes and were observed in symmetrical contact with somata and dendrites.
...
PMID:Gamma-aminobutyric acid-immunoreactivity in the rat hippocampus. A light and electron microscopic study with anti-GABA antibodies. 351 33
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