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)

Parvalbumin (PV)-immunoreactive neurons in rat neostriatum were studied under light and electron microscopes. A small number of neurons in the striatum were immunoreactive for PV (a Ca-binding protein). Most of them were also strongly immunoreactive for glutamate decarboxylase but were negative for NADPH-diaphorase activity. Light microscopic analysis revealed that PV-containing neurons have somata with fusiform or polygonal shape and are medium to large in size. The dendrites were smooth and cylindrical at the proximal portion but were varicose at the distal portion. Thin PV-immunoreactive fibers with large boutons were unevenly distributed in the striatum. Electron microscopy revealed that the somata of PV-immunoreactive neurons had a deeply indented nucleus with a nucleolus and often an intranuclear rod. These are the morphological features reported for interneurons of the striatum. Gap junctions formed between two neighboring PV-immunoreactive dendrites. A total of 175 boutons forming synapses with somata and dendrites of PV-immunoreactive neurons were examined. Of these, 115 were small in diameter (less than 1 micron), contained densely packed round vesicles and formed asymmetrical synapses mainly with dendrites. The other 60 boutons formed symmetrical synapses with somata and dendrites of PV-immunoreactive neurons. Both myelinated and unmyelinated axons with boutons were observed. PV-immunoreactive boutons had a diameter of 0.3-2 microns and contained round or elongated vesicles which were about 35 nm in diameter. The boutons formed symmetrical synapses with postsynaptic targets. Of the 100 PV-immunoreactive boutons, 51 were found on somata and proximal dendrites of medium-sized neurons containing a large, round, centrally located nucleus. The others formed synapses with dendrites of various sizes. It was occasionally observed that varicose dendrites free of spines were contacted by a large number of PV-immunoreactive boutons. The study indicates that, in the striatum, immunocytochemistry for PV selectively stains GABAergic interneurons and that the GABAergic interneurons are incorporated in a feed-forward inhibitory circuit of the striatum.
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PMID:Parvalbumin-immunoreactive neurons in the rat neostriatum: a light and electron microscopic study. 208 40

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

Previous observations have shown that the striatum contains a population of neurones that display immunoreactivity for calretinin. In order to morphologically characterize these neurones, sections of the rat striatum were immunostained to reveal calretinin and examined at both light and electron microscopic levels. The striatum contained a small population of calretinin-immunoreactive neurones, which were of medium-size (9-17 microns) and possessed few aspiny, infrequently branching dendrites which tapered to become very thin processes in their most distal portions. Although the calretinin-immunoreactive neurones were homogeneously distributed in the frontal plane, there was a marked rostrocaudal gradient with a much greater density of cells in the rostral than in the caudal parts of the striatum. At the ultrastructural level, calretinin-immunoreactive neurones were seen to possess an indented nucleus and to receive synaptic input from at least three types of boutons. In addition to the calretinin-immunoreactive neurones, the striatum also contained axons and terminal boutons that displayed immunoreactivity for calretinin. At least two types of immunoreactive terminals were identified, those forming symmetrical synaptic specialisations and those forming asymmetrical synaptic specialisations. Approximately 50% formed asymmetrical contacts with spines and 30% formed symmetrical synaptic contact with dendritic shafts. In an attempt to further chemically characterize the calretinin-containing neurones, double pre-embedding immunocytochemistry for calretinin and parvalbumin or choline acetyltransferase was carried out and calretinin immunocytochemistry was combined with histochemistry for NADPH-diaphorase. Analysis of these double-stained sections revealed that the population of calretinin-immunoreactive neurones was distinct from the populations of neurones containing parvalbumin, choline acetyltransferase or NADPH-diaphorase. It is concluded that: (1) on the basis of distribution, morphology, chemistry, ultrastructure and afferent synaptic input, the calretinin-immunoreactive neurones are distinct from the major classes of neurones that have been previously recognised in the striatum; (2) calretinin-immunoreactive terminals are heterogeneous and are probably derived from local calretinin-containing neurones and possibly other sources.
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PMID:Characterization of calretinin-immunoreactive structures in the striatum of the rat. 850 97

Nitric oxide (NO) is a cell-to-cell mediator involved in the regulation of vascular tone and in the mechanisms of host defence. Since uraemic syndrome is characterized by abnormalities in blood pressure and flow and by impairment of white cell function, we studied the regulation of nitric oxide synthase (NOS) activity by uraemic plasma. We used three different cellular types having different levels of NOS activity: tEnd.1 murine endothelial cell line transformed by mT oncogene of polyomavirus had a high NOS activity and expressed endothelial-NOS (eNOS) and inducible-NOS (iNOS) isoforms; human endothelial cells from cord umbilical vein (HUVEC) had low enzymatic activity and expressed only eNOS; finally, J774 murine macrophage line was characterised by iNOS induced after treatment with cytokines. We demonstrated that most (79%) of end-stage uraemic plasma studied inhibited NOS activity in tEnd.1 and in cytokine induced -J774, whereas they were ineffective on HUVEC. Twenty percent of plasma samples (14 of 67) activated NOS activity in tEnd.1 and in J774 cells, but not in HUVEC, suggesting the presence of molecule(s) which influence iNOS. The effect of plasma was not dependent on the type of haemodialysis treatment. A great number of plasmas from patients with moderate renal failure also inhibited NOS activity in tEnd.1, suggesting that the accumulation of molecules affecting NOS was caused by the renal failure rather than the haemodialytic treatment. However, the haemodialysis modified the effect of plasmas on NOS activity. Plasma taken after haemodialysis session showed a reduced inhibitory activity in tEnd.1 and in some cases it enhanced NOS activity. Simultaneously, molecules reducing NOS activity accumulated in the ultrafiltrate. The plasma concentration of NG-NG dimethyl-L-arginine (asymmetrical dimethylarginine, ADMA), an inhibitor of NOS, increased in end-stage uraemic patients and was reduced by haemodialysis. However, the concentrations reached in uraemic plasmas were lower than the ADMA IC50 on tEnd.1 NOS, indicating that this compound contributes with other molecules to the inhibitory effect of uraemic plasma. Haemodialysis reduced also the enhanced effect exerted by some plasmas on NOS in J774. Therefore, the effect of end-stage uraemic plasma on NOS activity derive from the balance between inhibitors and activators.
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PMID:Regulation of nitric oxide synthesis in uraemia. 853 31

Dietary supplementation of L-arginine, the precursor of endogenous NO, has been shown to enhance endothelial function in the cholesterol-fed rabbits. However, the mechanism by which dietary L-arginine accomplishes these effects has been unclear. In the present study we have assessed the plasma concentrations of L-arginine and of asymmetrical dimethylarginine (ADMA), a known endogenous inhibitor of NO synthase, in cholesterol-fed rabbits with or without dietary supplementation of L-arginine. Urinary nitrate excretion rates were assessed as an index of endogenous NO formation. Plasma L-arginine levels were not different between control and cholesterol-fed rabbits, but they were elevated nearly threefold in rabbits fed cholesterol + L-arginine. Plasma ADMA concentration increased about two-fold in hypercholesterolemia, but was unaffected by dietary L-arginine. Thus, dietary L-arginine elevated the plasma L-arginine/ADMA ratio above the normal level, and partly restored urinary nitrate excretion, which was decreased by hypercholesterolemia. We conclude that elevation of the L-arginine/ADMA ratio may at least partly explain the restored NO formation by exogenous L-arginine in hypercholesterolemia.
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PMID:Elevated L-arginine/dimethylarginine ratio contributes to enhanced systemic NO production by dietary L-arginine in hypercholesterolemic rabbits. 860 33

The rat nucleus accumbens contains medium-sized, spiny projection neurons and intrinsic, local circuit neurons, or interneurons. Sub-classes of interneurons, revealed by calretinin (CR) or parvalbumin (PV) immunoreactivity or reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry, were compared in the nucleus accumbens core, shell and rostral pole. CR, PV and NADPH-diaphorase-containing neurons are shown to form three non-co-localising populations in these three areas. No significant differences in neuronal population densities were found between the subterritories. NADPH-diaphorase-containing neurons could be further separated morphologically into three sub-groups, but CR- and PV-immunoreactive neurons form homogeneous populations. Ultrastructurally, NADPH-diaphorase-, CR- and PV-containing neurons in the nucleus accumbens all possess nuclear indentations. These are deeper and fewer in neurons immunoreactive for PV than in CR- and NADPH-diaphorase-containing neurons. CR-immunoreactive boutons form asymmetrical and symmetrical synaptic specialisations on spines, dendrites and somata, while PV-immunoreactive boutons make only symmetrical synaptic specialisations. Both CR- and PV-immunoreactive boutons form symmetrical synaptic specialisations with medium-sized spiny neurons and contact other CR- and PV-immunoreactive somata, respectively. A novel non-carcinogenic substrate for the peroxidase reaction (Vector Slate Grey, SG) was found to be characteristically electron-dense and may be distinguishable from the diaminobenzidine reaction product. We conclude that the three markers used in this study are localised in distinct populations of nucleus accumbens interneurons. Our studies of their synaptic connections contribute to an increased understanding of the intrinsic circuitry of this area.
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PMID:A light and electron microscopic study of NADPH-diaphorase-, calretinin- and parvalbumin-containing neurons in the rat nucleus accumbens. 870 62

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

A double immunocytochemical method combining the preembedding avidin biotin peroxidase complex technique and the postembedding immunogold technique was used to examine synaptic interactions between GABAergic and nitric oxide synthase containing neurons in the same tissue sections of the dorsal raphe nucleus of the Wistar white rat. Although a large number of immunogold stained GABAergic axon terminals were found to be presynaptic to dendrites containing nitric oxide synthase-like immunoreaction product, synapses between GABA-like immunoreactive axon terminals and nitric oxide synthase-like immunoreactive perikarya were rare. The labeled boutons were found to make symmetrical and asymmetrical synapses. No axo-axonic synapse was found. These results suggest that GABAergic neurons could modulate nitric oxide producing neurons in the dorsal raphe nucleus through direct synaptic relations.
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PMID:Electron microscopic study of GABAergic synaptic innervation of nitric oxide synthase immunoreactive neurons in the dorsal raphe nucleus in the rat. 898 44

Glutamate released in the basal ganglia is involved in the expression of clinical symptoms of neurodegenerative diseases like Parkinson's or Huntington's. Neostriatal neurons are the targets of glutamatergic inputs derived from the cortex and the thalamus acting via AMPA-type as well as other glutamate receptors. To determine the location of subunits of the AMPA subclass of glutamate receptors (GluR) in the rat neostriatum, we applied multiple immunocytochemical techniques using anti-peptide antibodies against the GluR1, GluR2/3, and GluR4 subunits at both the light and electron microscopic levels. All medium spiny efferent neurons, some of which were identified as striatonigral neurons, displayed immunoreactivity for GluR1 and GluR2/3 subunits. Double immunofluorescence revealed that at least 70-90% of parvalbumin-immunopositive GABAergic interneurons were immunoreactive for each of GluR1, GluR2/3, or GluR4 subunits and that at least 40% of choline acetyltransferase-immunopositive cholinergic interneurons were immunopositive for GluR1 or GluR4 subunits. The majority of nitric oxide synthase-immunopositive neurons had no detectable immunoreactivity for any of the AMPA receptor subunits. Electron microscopic analysis confirmed the presence of immunoreactivity for GluR1 and GluR2/3 in the perikarya of spiny neurons and interneurons and GluR4 in perikarya of interneurons only. GluR1 and GluR2/3 subunits were detected in dendrites and spines. A significant population of extrasynaptic receptors was revealed by pre-embedding immunogold labeling along the plasma membranes of perikarya, dendrites, and spines. Receptors were concentrated in the postsynaptic membrane specialization of asymmetrical synapses, as revealed by the postembedding immunogold method. Quantitative analysis demonstrated that immunoreactivity for the GluR1 and GluR2/3 subunits is higher at the periphery than at the middle of the postsynaptic membrane specialization. Our results demonstrate that AMPA receptor subunits are distributed widely and heterogeneously among striatal neurons and are concentrated on the postsynaptic membrane of asymmetrical synaptic specializations, although extrasynaptic receptors are also present.
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PMID:Cellular, subcellular, and subsynaptic distribution of AMPA-type glutamate receptor subunits in the neostriatum of the rat. 898 3

Neurons in the rat subiculum that are capable of producing nitric oxide were studied by using an antibody to the neuronal isoform of nitric oxide synthase (nNOS). In the light microscope, the staining pattern with the nNOS antibody closely resembled that seen following histochemical processing with nicotinamide adenine dinucleotide phosphate diaphorase. Immunostained neurons were found in all layers, and, in addition, large dendrites in the apical dendrite layer were also immunopositive. Although a few immunolabelled cells had the typical morphology of interneurons, most were found to have the characteristics of pyramidal neurons. In the subiculum, these immunoreactive pyramidal neurons were concentrated mainly in the most superficial cell layers and closest to the CA1 region, but pyramidal neurons in the CA1 layer of the hippocampus were consistently immunonegative. Immunopositive profiles in the subiculum were studied in the electron microscope and compared with unlabelled structures. Ultrastructural criteria suggest that both pyramidal and nonpyramidal subicular neurons are immunopositive for nNOS. Large, spiny dendrites and smaller, varicose dendrites were found to be immunoreactive for nNOS. Vesicle-containing profiles were probably presynaptic axons, and immunopositive boutons were seen to make symmetrical and asymmetrical synaptic contacts.
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PMID:Light and electron microscopic study of neuronal nitric oxide synthase-immunoreactive neurons in the rat subiculum. 960 72


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