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)

The findings from the present EM-autoradiography experiments identify the cerebellar nucleocortical projection as a mossy fiber-type pathway. In these studies orthogradely labelled axons and terminals were observed in the folial white matter and granule cell layer, with only background levels of silver grains over the Purkinje cell and molecular layers. Most nucleocortical axons synapsed within cerebellar glomeruli either at en passant contacts along dilated segments of unmyelinated axons or at multilobulated (terminal) expansions of the axons. Typically these synaptic junctions were of the asymmetrical type containing clear round vesicles. Usually, each labelled mossy fiber rosette synapsed on a large number of small terminal dendrites of granule cells; however, occasionally a series of 4-8 asymmetric contacts were noted on a single large dendrite. Labelled nucleocortical terminals were occasionally present in the nonglomerular neuropil between granule cell bodies where they contacted large dendrites of Golgi cells.
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PMID:EM-autoradiography of cerebellar nucleocortical terminals in the cat. 746 42

Anatomical relationships between tachykinin-containing terminals and neurons of the medial preoptic area that innervate the arcuate nucleus were studied using silver staining of the retrograde tracer wheat germ agglutinin-apoperoxidase-gold (WGA-ApoHRP-gold) complex injected in the arcuate nucleus and pre-embedding immunocytochemistry for neurokinin A (NKA). At the histological level, retrogradely labeled cells not stained for NKA were seen to be surrounded by numerous NKA-immunopositive punctate profiles, in particular in the dorsal part of the medial preoptic area. At the ultrastructural level, retrogradely labeled cell bodies and dendritic profiles displayed highly electron-dense silver particle accumulations over the cytoplasm. The were seen in synaptic contact with one or several NKA-immunoreactive axon terminals containing small clear vesicles and dense-cored vesicles. Such synapses were either symmetrical or asymmetrical. The occurrence of synaptic contacts between tachykinin terminals and cells innervating the arcuate nucleus in the medial preoptic region provides a morphological support for a tachykinergic regulation of preoptic afferences to the arcuate nucleus. These results suggest that tachykinins are implicated in the indirect control of neuronal activity in the arcuate nucleus notably via the preoptic area. Consequently, tachykinins are potentially able to regulate indirectly numerous neuroendocrine events involving the tuberoinfundibular system.
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PMID:Tachykinergic synaptic inputs to neurons of the medial preoptic region which project to the rat arcuate nucleus. 751 35

On the basis of the comparing of the distribution of beta-endorphin-like immunoreactive neuronal fibres and nitric oxide synthase-like immunoreactive neurons in the dorsal raphe nucleus, the synapses between the two immunocytochemically identified neurons were studied with a modified DAB-silver-gold intensification double immunostaining technique at the electron microscopic level. Although both of them can be found in the mediodorsal and medioventral parts of the dorsal raphe nucleus, the synapses between them could only be found in the mediodorsal part. The majority of the beta-endorphin-like immunoreactive neuronal fibers contained many dense-cored vesicles. The synapses made by beta-endorphin-like immunoreactive neuronal axon terminals on nitric oxide synthase-like immunoreactive neurons were both symmetrical and asymmetrical with the former predominant, especially in the axo-dendritic ones. beta-Endorphin-like immunoreactive perikarya could only be found in the ventrobasal hypothalamus. These findings suggest the possibility that the beta-endorphin- producing neurons in the ventrobasal hypothalamus could influence nitric oxide synthase-containing neurons in the dorsal raphe nucleus by synaptic relations.
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PMID:Immunoelectron microscopy of beta-endorphinergic synaptic innervation of nitric oxide synthase immunoreactive neurons in the dorsal raphe nucleus. 758 21

The pre-embedding double immunoreaction method was used to study synaptic relations of enkephalinergic and GABAergic neuronal elements in the ventrolateral part of the periaqueductal gray of the Wistar albino rat. The enkephalin-like neuronal elements were immunoreacted by the silver-gold intensified peroxidase-antiperoxidase method and the GABA-like immunoreactive neurons were immunoreacted by the unintensified peroxidase-antiperoxidase method. GABA-like immunoreactive neuronal somata were post-synaptic to both the enkephalin-like immunoreactive and the non-immunoreactive axon terminals. Enkephalin-like immunoreactive axon terminals were found to make synapses with GABA-like immunoreactive and non-immunoreactive dendrites. The synapses between the two kinds of chemically characterized neurons appeared to be both asymmetrical and symmetrical. Possible functional activity related to pain modulation, and synaptic relations between the enkephalinergic and GABAergic neurons in the periaqueductal gray and the dorsal raphe nucleus, are discussed.
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PMID:Immunoelectron microscopy of enkephalinergic innervation of GABAergic neurons in the periaqueductal gray. 788 16

Glutamate (Glu) is the most prevalent excitatory neurotransmitter in the brain and has been implicated in the regulation of GnRH secretion in several mammalian species, including the monkey. To investigate the neuroanatomical basis for Glu-GnRH interactions, we performed an immunocytochemical study at both the light and electron microscopic levels on the brains of four female and five male macaques. Initially, we determined the location of Glu-immunoreactive (-ir) elements using a monoclonal antibody specific for glutaraldehyde-fixed Glu (Glu-2) and 3,3'-diaminobenzidine-4-HCl (DAB). Glu-ir was observed in the cytoplasm and to a variable degree in the nuclei of neurons in the diencephalon. Cytoplasmic staining was particularly intense in numerous neurons in the arcuate nucleus, supraoptic nucleus, and many paraventricular nucleus neurons. Short Glu-ir processes were evident in these and other hypothalamic regions and were extremely dense in the infundibular stalk and median eminence. Prior absorption of the Glu-2 antibody with a Glu-glutaraldehyde-BSA conjugate completely abolished all immunostaining in both neuronal nuclei and cytoplasm. Double label Glu-GnRH immunostaining for light microscopy was performed using Glu-2 and DAB without enhancement, and a polyclonal antibody (LR1 or LR2) with silver-enhanced DAB for Glu and GnRH, respectively. Glu-ir interactions with GnRH-ir cell bodies were not apparent, but a few Glu-ir axons seemed to contact GnRH-ir dendrites in the organum vasculosum of the lamina terminalis, medial septum, and arcuate nucleus regions. Reciprocal interactions occurred more frequently, however, in which GnRH-ir axons and dendritic fibers engaged Glu-ir cell bodies en passant, particularly toward the medial and posterior hypothalamus. For ultrastructural analyses, Glu-ir elements were stained with the Glu-2 antibody and 15 nm immunogold or DAB. Electron microscopy demonstrated that Glu-ir was associated with clear microvesicles within the neuronal cytoplasm. Glu-ir processes made classical asymmetrical synapses with one another and received asymmetrical synapses from unlabeled afferents. In sections double labeled for Glu with immunogold and for GnRH with DAB, axo-somatic interactions were not observed. However, axo-dendritic Glu-GnRH synapses were seen, which usually exhibited Glu-ir labeling of terminal vesicles and inconsistent postsynaptic densities, with GnRH-ir neurosecretory granules sometimes congregated in the apposing dendrite or spine. Surprisingly, reverse GnRH-Glu interactions were observed more frequently.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Glutamate-immunoreactive neurons and their gonadotropin-releasing hormone-neuronal interactions in the monkey hypothalamus. 790 10

In situ hybridization was used to detect the expression of the c-ets1 protooncogene during formation of the germ layers in the chick blastodisc. c-ets1 transcripts were present during the gastrulation process, i.e. when the mesodermal cells invaginated. The expression became down-regulated in lateral plate and the dorsal part of the somites while an intense signal was retained in the intermediate cell mass. When vasculogenesis started, c-ets1 transcripts labelled blood islands and endothelial cells. Before the mesoderm split, transcripts were present over the whole layer, more abundant however on its ventral side in contact with the endoderm. After the mesoderm split, silver grains became distributed asymmetrically: splanchnopleural mesoderm expressed c-ets1 messengers all over while expression in the somatopleural mesoderm was restricted to a few profiles corresponding to small endothelial cell groups. This asymmetrical distribution of c-ets1 transcripts is in agreement with our previous experimental findings establishing the different potentialities of the two mesodermal layers regarding hemopoiesis, vasculogenesis and angiogenesis processes.
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PMID:Expression of C-ETS1 in early chick embryo mesoderm: relationship to the hemangioblastic lineage. 808 77

The sources of GABAergic innervation to granule cells were studied to establish how the basic cortical circuit is implemented in the dentate gyrus. Five types of neuron having extensive local axons were recorded electrophysiologically in vitro and filled intracellularly with biocytin (Han et al., 1993). They were processed for electron microscopy in order to reveal their synaptic organization and postsynaptic targets, and to test whether their terminals contained GABA. (1) The hilar cell, with axon terminals in the commissural and association pathway termination field (HICAP cell), formed Gray's type 2 (symmetrical) synapses with large proximal dendritic shafts (n = 18), two-thirds of which could be shown to emit spines, and with small dendritic branches (n = 6). Other boutons of the HICAP neuron were found to make either Gray's type 1 (asymmetrical) synapses (n = 4) or type 2 synapses (n = 6) with dendritic spines. Using a highly sensitive silver-intensified immunogold method for the postembedding visualization of GABA immunoreactivity, both the terminals and the dendrites of the HICAP cell were found to be immunopositive, whereas its postsynaptic targets were GABA-immunonegative. The dendritic shafts of the HICAP cell received synapses from both GABA-negative and GABA-positive boutons; the dendritic spines which densely covered the main apical dendrite in the medial one-third of the molecular layer received synapses from GABA-negative boutons. (2) The hilar cell, with axon terminals distributed in conjunction with the perforant path termination field (HIPP cell), established type 2 synapses with distal dendritic shafts (n = 17), most of which could be shown to emit spines, small-calibre dendritic profiles (n = 2) and dendritic spines (n = 6), all showing characteristics of granule cell dendrites. The sparsely spiny dendrites of the HIPP cell were covered with many synaptic boutons on both their shafts and their spines. (3) The cell with soma in the molecular layer had an axon associated with the perforant path termination field (MOPP cell). This GABA-immunoreactive cell made type 2 synapses exclusively on dendritic shafts (n = 20), 60% of which could be shown to emit spines. The smooth dendrites of the MOPP cell were also restricted to the outer two-thirds of the molecular layer, where they received both GABA-negative and GABA-positive synaptic inputs.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Subdivisions in the multiple GABAergic innervation of granule cells in the dentate gyrus of the rat hippocampus. 826 Nov 18

The preembedding double immunoreaction method was used to study interrelations of enkephalinergic and GABAergic neuronal elements in the dorsal raphe nucleus of the Wistar albino rat. The enkephalin-like neuronal elements were immunoreacted by the peroxidase-antiperoxidase method and silver-gold intensified, which showed strongly and was specific. The GABA-like immunoreactive neurons were immunoreacted by the peroxidase-antiperoxidase method only. GABA-like neural somata were postsynaptic to both the enkephalin-like immunoreactive and the non-immunoreactive axon terminals. The enkephalin-like immunoreactive axon terminals were also found to synapse GABA-like immunoreactive dendrites. The GABA-like immunoreactive neuronal elements were also found to receive synapses from other non-immunoreactive as well as GABA-like immunoreactive axon terminals. Almost all of the synapses appeared to be asymmetrical. Possible functional activity of interactions among the enkephalinergic, GABAergic, and serotonergic neuronal elements in the dorsal raphe nucleus are discussed.
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PMID:Enkephalinergic innervation of GABAergic neurons in the dorsal raphe nucleus of the rat. 837 9

Elasmobranchs possess a well-developed cerebellum with an associated cerebellar nucleus. To determine whether the organization of this nucleus is comparable with that of the deep cerebellar nuclei of mammals, we studied the dogfish cerebellar nucleus with light microscopic methods (Nissl stain, Golgi method, reduced silver stain, NADPH-diaphorase histochemistry and immunocytochemistry) and with electron microscopy. We found the dogfish cerebellar nucleus to consist of about 1,050 large neurons, the ratio of Purkinje cells to cerebellar nucleus neurons being about 17:1. Immunocytochemistry showed large glutamatergic neurons in the main portions of the nucleus and small glutamate- and/or alpha-aminobutyric acid (GABA)-immunoreactive cells in the subventricular region of the nucleus. Large glutamatergic neurons corresponded to bipolar or triangular cells revealed by Golgi methods. Application of horseradish peroxidase to the cerebellar cortex produced the labelling of beaded fibres of Purkinje cells in the cerebellar nucleus. Unlike in mammals, GABAergic innervation of the cerebellar nucleus was scare: Purkinje cell axon terminals in the cerebellar nucleus did not appear to be GABA-immunoreactive, most GABAergic fibres being found in the subventricular neuropile. Some fibres immunoreactive to serotonin and somatostatin were also observed in the subventricular neuropile of the cerebellar nucleus. Three neuron types were distinguished with electron microscopy (types A to C). Type A cells were abundant and smooth-surfaced, and appeared to correspond to Golgi-impregnated neurons and large glutamate-immunoreactive cells. Type B neurons were scarce and possessed dendrites covered by sessile or stalked spines. Type C neurons were small cells located mainly in the medialmost region of the nucleus and corresponded to subventricular glutamate- and GABA-immunoreactive cells. Six types of synaptic bouton were observed (types I to VI). The most abundant (type I boutons) made symmetrical contacts and appeared to correspond to Purkinje cell axons. Type I boutons were the only type observed on perikarya and initial axon segments of type A cells. Type IV and type V boutons made complex glomerular-like asymmetrical contacts with spines of type B cells. Type VI boutons appeared to correspond to peptidergic and/or monoaminergic axons. The functional significance of these results is discussed.
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PMID:Organisation of the cerebellar nucleus of the dogfish, Scyliorhinus canicula L.: a light microscopic, immunocytochemical, and ultrastructural study. 874 38

The cellular and subcellular localization of the GluRA, GluRB/C and GluRD subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type glutamate receptor was determined in the rat hippocampus using polyclonal antipeptide antibodies in immunoperoxidase and immunogold procedures. For the localization of the GluRD subunit a new polyclonal antiserum was developed using the C-terminal sequence of the protein (residues 869-881), conjugated to carrier protein and absorbed to colloidal gold for immunization. The purified antibodies immunoprecipitated about 25% of 3[H]AMPA binding activity from the hippocampus, cerebellum or whole brain, but very little from neocortex. These antibodies did not precipitate a significant amount of 3[H]kainate binding activity. The antibodies also recognize the GluRD subunit, but not the other AMPA receptor subunits, when expressed in transfected COS-7 cells and only when permeabilized with detergent, indicating an intracellular epitope. All subunits were enriched in the neuropil of the dendritic layers of the hippocampus and in the molecular layer of the dentate gyrus. The cellular distribution of the GluRD subunit was studied more extensively. The strata radiatum, oriens and the dentate molecular layer were more strongly immunoreactive than the stratum lacunosum moleculare, the stratum lucidum and the hilus. However, in the stratum lucidum of the CA3 area and in the hilus the weakly reacting dendrites were surrounded by immunopositive rosettes, shown in subsequent electron microscopic studies to correspond to complex dendritic spines. In the stratum radiatum, the weakly reacting apical dendrites contrasted with the surrounding intensely stained neuropil. The cell bodies of pyramidal and granule cells were moderately reactive. Some non-principal cells and their dendrites in the pyramidal cell layer and in the alveus also reacted very strongly for the GluRD subunit. At the subcellular level, silver intensified immunogold particles for the GluRA, GluRB/C and GluRD subunits were present at type 1 synaptic membrane specializations on dendritic spines of pyramidal cells throughout all layers of the CA1 and CA3 areas. The most densely labelled synapses tended to be on the largest spines and many smaller spines remained unlabelled. Immunoparticle density at type 1 synapses on dendritic shafts of some non-principal cells was consistently higher than at labelled synapses of dendritic spines of pyramidal cells. Synapses established between dendritic spines and mossy fibre terminals, were immunoreactive for all studied subunits in stratum lucidum of the CA3 area. The postembedding immunogold method revealed that the AMPA type receptors are concentrated within the main body of the anatomically defined type 1 (asymmetrical) synaptic junction. Often only a part of the membrane specialization showed clustered immunoparticles. There was a sharp decrease in immunoreactive receptor density at the edge of the synaptic specialization. Immunolabelling was consistently demonstrated at extrasynaptic sites on dendrites, dendritic spines and somata. The results demonstrate that the GluRA, B/C and D subunits of the AMPA type glutamate receptor are present in many of the glutamatergic synapses formed by the entorhinal, CA3 pyramidal and mossy fibre terminals. Some interneurons have a higher density of AMPA type receptors in their asymmetrical afferent synapses than pyramidal cells. This may contribute to a lower activation threshold of interneurons as compared to principal cells by the same afferents in the hippocampal formation.
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PMID:High-resolution immunogold localization of AMPA type glutamate receptor subunits at synaptic and non-synaptic sites in rat hippocampus. 884 93


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