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PubMed2005

NADPH-diaphorase positive neurons of the rat hippocampal formation: regional distribution, total number and colocalization with calcium binding proteins.

The present study aimed to asses the total number and distribution of the NADPH-diaphorase-positive non-pyramidal neurons in Ammon's horn and dentate gyrus of rat hippocampal formation. Cell bodies were counted according to the "disector" principle. The total numbers varied from 27 000 to 32 400. In all strains, approximately one third of the NADPH-diaphorase-reactive non-principal cells were found in the dentate gyrus and the remaining two thirds were within the Ammon's horn. Analysis of the dorsoventral differences revealed that approximately 70% of NADPH-diaphorase-positive cells were in the dorsal and 30% in the ventral hippocampus. Distribution of NADPH-diaphorase-reactive cells in the different layers of the dentate gyrus and Ammon's horn was similar in all strains. Double-labelling studies revealed colocalization of NADPH-diaphorase with calretinin, but none with calbindin or parvalbumin. NADPH-diaphorase-positive neurons appear to form the largest chemically identified subpopulation of the GABAergic inhibitory cell population of the hippocampal formation.

Animals↗

PubMed2006

[Colocalized expression of Fas and Fas-ligand in acute pancreatitis and its correlation with cell apoptosis].

OBJECTIVE: To study the expressions of Fas and Fas-Ligand (FasL) genes in rats with acute pancreatitis (AP) and their relation to apoptosis of pancreatic acinar cells. METHODS: Rat models of acute pancreatitis with varied severity were established by retrograde injection of sodium taurocholate at different concentrations via the apancreatobiliary duct. The expressions of Fas and FasL mRNAs and proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. The apoptosis of acinar cells was quantified by in situ nick ending-labeling technique. RESULTS: of expressions fas, FasL mRNA and protein were colocalized in normal pancreatic acinar cells. In pancreatic tissue with less severe inflammation, the expressions of Fas and FasL mRNA increased significantly, and the apoptosis index of the acinar cells was also elevated; with the increase in the severity of the pancreatitis, the expression of Fas and FasL mRNAs were gradually lowered and apoptosis index of the acinar cells was increased. CONCLUSION: Fas/FasL system might be involved in the renewal and homeostasis of normal pancreatic tissue, and constitute an important pathway mediating the apoptosis of pancreatic acinar cells in AP.

Acute Disease↗

PubMedDate not supplied

Distribution and colocalization of delta sleep-inducing peptide and luteinizing hormone-releasing hormone in the aged human brain: an immunohistochemical study.

The distributions of delta sleep-inducing peptide (DSIP)- and luteinizing hormone-releasing hormone (LHRH)-immunoreactive neurons were investigated in the human brain with special emphasis on the basal forebrain (from the septum to the hypothalamus), using indirect immunofluorescence. With a modified elution technique, sequential stainings on the same section showed that DSIP- and LHRH-immunoreactivities were often colocalized. Small numbers of LHRH/DSIP-immunoreactive cells were essentially detected in the diagonal band of Broca, the medial septum and the ventral hypothalamus. The richest areas displaying fibres and terminal-like structures were the preoptic area, the ventromedial and ventrolateral hypothalamic areas, the periventricular region and certain circumventricular organs (i.e. median eminence, vascular organ of the lamina terminalis). Few isolated fibres were observed in the subfornical organ. The topographical relationships between DSIP- and LHRH-immunoreactivities in the neurosecretory systems suggest that DSIP may play a role as important as that of LHRH.

Aged↗

PubMedDate not supplied

Neurons with neurokinin B mRNA in the rat magnocellular basal nucleus: distribution, projection and colocalization studies.

Mapping and cortical projections of neurons containing neurokinin B (NKB) mRNA in the rat basal forebrain were studied using hybridization histochemistry and retrograde labeling. Neurokinin B mRNA was found in a small proportion of the neurons present in the magnocellular basal nucleus that project to the cortex. Most of these neurons projected to the frontal and parietal cortices, whereas only few projected to the occipital cortex and almost none to allocortical areas, including the olfactory bulb. NKB mRNA colocalization with galanin or substance P mRNAs, both found within neurons of the magnocellular basal nucleus, was not detected there. These results demonstrate a novel diffuse neocortical tachykinin input from the basal forebrain, in addition to the well-known cholinergic one.

Animals↗

PubMed1989

Immunofluorescence colocalization of the 90-kDa heat-shock protein and microtubules in interphase and mitotic mammalian cells.

A mouse monoclonal antibody (AC88) that was raised against the 88-kDa heat-shock protein of the water mold, Achlya ambisexualis, and that cross-reacts with the 90-kDa mammalian heat-shock protein (hsp90), and an antibody against tubulin were used to localize hsp90 and microtubules, respectively, in the same cultured rat endothelial and PtK1 epithelial cells by indirect immunofluorescence. AC88 and tubulin antibodies labeled the same structures in cells at all stages of the cell cycle, regardless of whether cells were permeabilized before or after fixation. Labeling of cell structures by both AC88 and anti-tubulin antibodies was identically affected by treating cells with colcemid. Double labeling with AC88 and anti-tubulin antibodies in interphase and mitotic cells is consistent with the conclusion that all microtubules are labeled and that no subclass of microtubules is preferentially labeled. Fluorescent labeling by AC88 was prevented by preabsorption of the antibody with purified rat hsp90 but was unaffected by preabsorption with purified 6S tubulin dimer. In contrast to AC88, fluorescent labeling by an anti-tubulin antibody was prevented by preabsorption with tubulin dimer but was unaffected by preabsorption with rat hsp90. Western-blot analysis demonstrated no cross-reactivity of AC88 for tubulin and no cross-reactivity of the anti-tubulin antibody for hsp90. A polyclonal antiserum fraction from a rabbit immunized with the 89-kDa heat-shock protein from chicken also labeled the mitotic apparatus in dividing cells and, somewhat less distinctly, fibrous structures in interphase cells. Labeling by hsp89 anti-serum was prevented by absorption with hsp90. AC88 also labeled microtubules in cultured mouse (L929 and 3T3), rat (endothelium and TRST), hamster (CHO) and primate (BSC, COS-1 and HeLa) cell lines. The demonstration of colocalization of hsp90 with microtubules should provide a valuable clue to eventual understanding of the cellular function of this ubiquitous, conserved and abundant stress-response protein.

Animals↗

PubMed1988

Colocalization and coprecipitation of ankyrin and Na+,K+-ATPase in kidney epithelial cells.

Interactions between integral proteins of the plasma membrane and the cytoskeleton may be important for localizing certain membrane proteins in a nonrandom fashion at specialized domains of the cell surface. Here, we show that ankyrin, the key protein for the linkage of the erythrocyte anion exchanger (band 3) to the spectrin-based membrane cytoskeleton, is also present in kidney distal tubular cells where ankyrin is precisely colocalized with Na+,K+-ATPase. Both proteins are confined to the basolateral plasma membrane and are absent from the apical membrane, the junctional complex and the membrane surface that contacts the basal lamina. Purified Na+,K+-ATPase of sheep and pig kidney contains a binding site for erythrocyte ankyrin as demonstrated by immunoprecipitation experiments. A band 3-like binding site for ankyrin is likely, since binding of ankyrin to Na+,K+-ATPase could be inhibited in a competitive fashion by the isolated cytoplasmic domain of erythrocyte band 3.

Animals↗

PubMed1987

The v- and c-myc oncogene proteins colocalize in situ with small nuclear ribonucleoprotein particles.

The intranuclear distribution of the v-myc and c-myc oncogene proteins were studied by immunofluorescence and immunoelectron microscopy. The nuclear distribution pattern of these proteins is shown to be identical to the distribution of small nuclear ribonucleoprotein particles (snRNPs). Colocalization was observed in cells expressing either the v- or c-myc proteins or in cells microinjected with the recombinant human c-myc protein. Immunolocalization studies revealed the v-myc protein and snRNPs to be concentrated within a nuclear network which excludes the nucleolus, nuclear pore-lamina complex, and portions of the nucleoplasm which contain the bulk of DNA. These results identify a nuclear region enriched in the myc-oncogene protein and snRNPs and raise the possibility that these nuclear constituents may function in related processes.

Animals↗

PubMed1985

Platelet membrane topography: colocalization of thrombospondin and fibrinogen with the glycoprotein IIb-IIIa complex.

The distribution of platelet thrombospondin (TSP), fibrinogen, and glycoproteins IIb-IIIa (GPIIb-IIIa) and GPIb were studied in resting and activated human platelets using frozen thin-section immunoelectron microscopy. In resting platelets, TSP and fibrinogen were found within alpha granules and not on the platelet surface. In unstimulated platelets, GPIIb-IIIa and GPIb were distributed diffusely over the platelet membrane as well as within the body of the platelets. Upon thrombin or A23187 stimulation, TSP, fibrinogen, and GPIIb-IIIa colocalized on the platelet membrane and the canalicular system as well as on pseudopodia and between adherent platelets. GPIb distribution was unchanged by platelet activation. The findings support the hypothesis that a macromolecular complex of TSP-fibrinogen and GPIIb-IIIa forms on the activated platelet membrane.

Blood Platelets↗

PubMed1987

Neuronal colocalization of peptides, catecholamines, and catecholamine-synthesizing enzymes in guinea pig paracervical ganglia.

The patterns of colocalization of neuropeptides, catecholamines, and catecholamine-synthesizing enzymes were examined in principal neurons and nerve terminals in guinea pig paracervical ganglia using a double-labeling immunohistochemical procedure. A small proportion of nerve cell bodies (less than 10%) had the characteristics of catecholamine-synthesizing neurons and presumably were noradrenergic. Another 50% of the nerve cell bodies contained immunoreactivity (IR) to dopamine-beta-hydroxylase (DBH), but did not have any other characteristics of noradrenergic neurons; they did not contain detectable catecholamines, or IR to dopa decarboxylase (DDC) or tyrosine (TH) hydroxylase, nor did they take up exogenous catecholamines. Half of the catecholamine neurons had neuropeptide Y (NPY)-IR, and a small number (0.5% total neurons) had somatostatin (Som)-IR. Most of the non-noradrenergic neurons with DBH-IR (40-50% total neurons) contained IR for dynorphin (Dyn), NPY, and vasoactive intestinal peptide (VIP), and about half of them (20-25% total) also contained Som-IR. Ten to twenty percent of neurons contained IR to Som, but not to any other antigen examined here. Nerve terminals with substance P (SP)-IR or enkephalin (Enk)-IR were prominent in all ganglia. SP-IR fibers formed dense baskets only around those neurons with DBH/Dyn/NPY/VIP (+/- Som)-IR, while fibers with very bright Enk-IR were associated selectively with those neurons with Som-IR alone. In addition, most TH-IR nerve cell bodies were surrounded by NPY-IR varicose nerve fibers. In conclusion, this analysis of combinations of peptides and enzymes contained in principal neurons of the paracervical ganglia allows us to identify as many as 11 different neuron populations. The functional significance of the presence of the same neuropeptide (e.g., NPY) in different neuron populations is as yet unknown. Some of these classes of neurons are associated specifically with immunohistochemically distinct types of presynaptic nerve fibers, which suggests that different immunohistochemically defined classes of neurons represent different functional pathways.

Animals↗

PubMed1994

Colocalization of somatostatin with GABA or glutamate in distinct afferent terminals presynaptic to the Mauthner cell.

The presence of somatostatin in afferent fibers impinging on the goldfish Mauthner (M-) cell was determined using immunohistochemical methods, combined with confocal and electron microscopy, and the relationship of this peptide with inhibitory and excitatory terminals was studied. Somatostatin-reactive boutons were present only on the distal part of the M-cell's lateral dendrite. Somatostatin immunoreactivity was observed in typical large myelinated club endings (LMCEs) corresponding to mixed (electrical and chemical) eighth nerve primary afferent fibers. The axoplasm of these fibers contained dense-core vesicles (DCVs) dispersed among round vesicles. We have made a novel finding that the excitatory transmitter glutamate is present in LMCEs. Colocalization of this amino acid with somatostatin was detected in 75% of these endings using postembedding staining with gold particles of various sizes. The other structures labeled by somatostatin antibody were found to be small vesicle boutons (SVBs), which establish symmetrical synapses and contain a population of pleiomorphic vesicles with DCVs scattered among them. Double labeling with antibodies against glutamic acid decarboxylase and GABA allowed the definition of three types of biochemically characterized terminals: [somatostatin-GABA], [GABA], and [somatostatin]. However, the occurrence of DCVs in SVBs stained for GABA alone suggests that neuropeptides other than somatostatin may also coexist with GABA in this class of boutons. The coexistence of somatostatin with both inhibitory and excitatory neurotransmitters acting on the same region of a postsynaptic cell is discussed in relation to the role postulated for this peptide in synaptic plasticity.

Afferent Pathways↗

PubMed1994

Colocalization of myocardial fibrosis and inflammatory cells in rats.

BACKGROUND: Left ventricular overload and aging lead to an increase in fibrosis in the rat cardiac interstitium. The relationship between fibrosis, fibroblast activity, and inflammatory cell infiltration, was explored in spontaneously hypertensive rats (SHR) and Wistar controls. EXPERIMENTAL DESIGN: The left ventricle of three groups of eight SHR and eight Wistar controls hearts were sectioned for light microscopy, immunohistochemistry, and in situ hybridization with a cDNA probe encoding the murine alpha 1 chain of type I collagen. Fibrosis was measured morphometrically. Monoclonal antibodies directed against Ia antigen, CD8+ cytotoxic, CD4+ helper lymphocytes and monocyte/macrophages were used to localize and quantify the inflammatory cells. RESULTS: In 2-month-old rats, with nearly normal interstitial cardiac tissue, fibroblasts expressing collagen mRNA were located around coronary vessels. The areas of fibrosis and interstitial cellular infiltration were more extensive in 22-month-old rats than in 12-month-old rats and greater in SHR than in Wistar. Fibroblasts expressing collagen mRNA were mainly found at the border between fibrosis and myocytic cells, and were always colocalized with lymphocytes and macrophages. The interstitial areas of fibrosis and collagen I expressing fibroblasts had the same pattern of infiltrating cells in normotensive rats than in SHR. Fibrosis and the density of macrophages and CD4+ lymphocytes were correlated. CONCLUSIONS: Thus, fibroblast activity could be closely related to the presence of lymphocytes and macrophages in the myocardium of spontaneously hypertensive and aged rats.

Aging↗

PubMed1993

Colocalization of low- and high-affinity NGF receptors on PC12 cells, C6 glioma cells and dorsal root ganglion neurons.

The biological responsiveness of neural cells to nerve growth factor (NGF) appears to require expression and ligand binding to both the low-affinity NGF receptor (LNGFR) and the proto-oncogene product trk, the latter being a receptor tyrosine kinase. Immunolocalization of the LNGFR and the high-affinity component of the NGF receptor, trk (HNGFR) was studied by electron microscopic morphometric analysis on cultured PC12 pheochromocytoma cells, C6 glioma cells and neonatal rat dorsal root ganglia neurons using a double immunogold labeling technique. Two receptor-specific antibodies, anti-LNGFR monoclonal antibody 192-IgG and a polyclonal antibody against the 14 carboxy-terminal amino acids of the Trk protein, were utilized in conjunction with immunoglobulin conjugated to colloidal gold particles of different sizes. All cells treated with NGF (50 ng/ml) displayed significant colocalization of LNGFR/HNGFR-like immunoreactivity. Gold particles associated with LNGFR (LNGFR-like immunoreactivity) were frequently seen near 2 or 3 (or more) particles delineating the HNGFR on all cell surfaces. Positive Trk-like immunoreactivity (HNGFR) thus seems to localize in close proximity to LNGFRs in at least these cell types.

Animals↗

PubMed1993

The glucose transporter GluT4 and secretory carrier membrane proteins (SCAMPs) colocalize in rat adipocytes and partially segregate during insulin stimulation.

Secretory carrier membrane proteins (SCAMPs) mark the recycling system for the insulin-responsive glucose transporter, GluT4, in rat adipocytes. Anti-GluT4 and anti-SCAMP antibodies each immunoadsorbed vesicles containing both antigens from a low density microsomal fraction that is enriched in both antigens. The immunoadsorbed vesicles also contain VAMPs (synaptobrevins), synaptic vesicle membrane proteins. All three antigens were colocalized in low density microsomal vesicles from both basal and insulin-stimulated adipocytes. The SCAMPs have the same electrophoretic mobility as a major polypeptides detected in GluT4 vesicles. During insulin stimulation, 40% each of GluT4 and VAMPs redistribute from low density microsomes to the plasma membrane fraction; however, < 10% of the SCAMPs redistribute. Immunocytochemical staining of adipose tissue shows almost complete coincidence of SCAMPs and GluT4 in the basal state and extensive redistribution of both antigens to the cell periphery during insulin stimulation. Segregation of antigens during stimulation is not as distinct as observed by fractionation, although there are regions at the cell border where the SCAMPs appear more concentrated than GluT4. These data suggest that during insulin stimulation, in contrast to the behaviour of GluT4, SCAMPs remain tightly associated with the recycling system.

Adipose Tissue↗

PubMed1995

Neurothelin: amino acid sequence, cell surface dynamics and actin colocalization.

Neurothelin is a cell surface protein of chicken endothelial cells at the blood-brain barrier and also of pigment epithelial cells forming the blood-eye barrier. Peptide sequencing of affinity-purified neurothelin revealed that it is likely to be identical with the protein called HT7. It belongs to the immunoglobulin superfamily having two extracellular C2-type domains, a membrane spanning region and a cytoplasmic tail. During development neurothelin cell surface localization changed on pigment epithelial cells. In early embryogenesis neurothelin was found preferentially at lateral sites of neighboring epithelial cells, but after hatching, predominantly on basal cell surfaces and on apical microvilli of epithelial cells that contact retinal photoreceptors. Disruption of cell-cell contacts induced a rapid change of neurothelin distribution on the cell surface in vitro as could be shown by confocal laser microscopy. Disintegration of microfilaments by cytochalasin D hampered this specific cell surface rearrangement of neurothelin, whereas depolymerization of microtubules by demecolcine had no effect. In double-labeling experiments neurothelin and F-actin were colocalized. The data suggest that the polarized cell surface distribution of neurothelin is influenced intracellularly by F-actin and extracellularly by cell-cell interactions.

Actin Cytoskeleton↗

PubMed1996

Nuclear signaling induced by ionizing radiation involves colocalization of the activated p56/p53lyn tyrosine kinase with p34cdc2.

The Src-like protein-tyrosine kinase p56/p53lyn associates with cell membranes and transduces signals from activated cell surface receptors. In the present work, cell fractionation and confocal microscopy studies demonstrate expression of Lyn in the nucleus. We also demonstrate that exposure of intact cells to ionizing radiation is associated with selective activation of nuclear Lyn. Similar findings have been obtained following irradiation of purified nuclei. Immunoprecipitation studies of nuclear lysates demonstrate radiation-induced binding of Lyn to p34cdc2. Nuclear colocalization of Lyn with Cdc2 has been confirmed by confocal microscopy. Other studies with glutathione S-transferase-Lyn fusion proteins demonstrate that the binding of Lyn to nuclear Cdc2 is associated with inhibition of Cdc2 activity. These findings suggest that the association of activated Lyn with Cdc2 in the nucleus may contribute to regulation of a DNA damage-dependent premitotic checkpoint.

CDC2 Protein Kinase↗

PubMed1996

Colocalization of three types of intermediate filament proteins in perisinusoidal stellate cells: glial fibrillary acidic protein as a new cellular marker.

The presence and the colocalization of the three intermediate filament proteins, glial fibrillary acidic protein (GFAP) and the marker of mesenchymal liver cells, vimentin, were studied by an immunofluorescence double-labeling technique in cultures of isolated rat perisinusoidal stellate cells (PSC) and hepatocytes, in cocultures of isolated PSC and hepatocytes as well as in cryostat sections of rat liver. GFAP and vimentin immunoreactivities were localized in cultured PSC which were identified by the presence of the cellular marker desmin, another intermediate filament protein, or the stellate morphology to be seen after staining for one of three intermediate filament proteins. Both GFAP and vimentin were strongly expressed in the perinuclear region and the cell processes of cultured PSC. Staining for GFAP highly coincided with that for vimentin or desmin in cultured PSC and with that for vimentin in the liver sections. Desmin-positive cells were always also GFAP-positive. However, of the GFAP-positive cells only an estimated 50% were found desmin-positive. The coexpression of desmin and GFAP in the same cells appear to be unique, since apparently it has not been previously reported for any other cell type. Almost all of the vimentin-positive cells in hepatocyte culture were also expressing GFAP. Since desmin was not found in all of the cultured cells with PSC morphology, GFAP is suggested as a more reliable marker for PSC than desmin.

Animals↗

PubMed1996

Gonadotropin-releasing hormone and NMDA receptor gene expression and colocalization change during puberty in female rats.

During development, an increase in gonadotropin-releasing hormone (GnRH) release occurs that is critical for the initiation of puberty. This increase is attributable, at least in part, to activation of the GnRH neurosecretory system by inputs from neurotransmitters, such as glutamate, acting via NMDA receptors. We examined changes in GnRH and NMDA-R1 gene expression by RNase protection assay of preoptic area-anterior hypothalamic (POA-AH) dissections of female rats undergoing normal puberty or in which precocious puberty was induced by treatment with the glutamate agonist NMA. GnRH mRNA levels increased significantly throughout normal development; this was accelerated by treatment with NMA. NMDA-R1 mRNA levels increased only between P10 and P20. The acceleration of the elevation in GnRH mRNA levels by NMDA suggests that a stimulation of GnRH gene expression may be a rate-limiting factor for the onset of puberty. This is attributable to a post-transcriptional mechanism because GnRH primary transcript levels, an index of proGnRH gene transcription, were not observed to change during puberty. Alterations in the colocalization of GnRH neurons with the NMDA-R1 subunit during puberty also were assessed immunocytochemically. The percentage of GnRH neurons that double-labeled with NMDA-R1 was 2% in prepubertal rats and 3% in pubertal rats; this increased to 19% in postpubertal rats. Taken together, these studies suggest that an increase in glutamatergic input to GnRH neurons plays a role in the increase in GnRH release and gene expression that occurs at the initiation of puberty.

Animals↗

PubMed1996

DNA damage and apoptosis in Alzheimer's disease: colocalization with c-Jun immunoreactivity, relationship to brain area, and effect of postmortem delay.

Many neurons in Alzheimer's disease (AD) exhibit terminal deoxynucleotidyl transferase (TdT) labeling for DNA strand breaks with a distribution suggestive of apoptosis. We have shown previously that immunoreactivity for c-Jun is elevated in AD and found in association with neuronal pathology. In addition, cultured neurons undergoing beta-amyloid-mediated apoptosis exhibit a selective and prolonged induction of c-Jun. Consequently, we conducted double-labeling experiments to examine whether c-Jun is associated with DNA strand breaks in AD tissue; we observed a strong colocalization between these markers. As would be predicted based on the distribution of AD pathology, we also found that TdT labeling was prominent in the entorhinal cortex, but absent or at very low levels in cerebellum. Furthermore, we confirmed that postmortem delay (PMD) does not affect TdT labeling within the limits used for tissue used in this study. However, in contrast to previous studies, we report an increase in TdT labeling with more extended PMDs. Finally, gel electrophoresis of genomic DNA isolated from AD and control cases failed to reveal evidence for either an apoptotic or a necrotic mechanism of cell death in AD, possibly because of a low number of cells actually undergoing cell death at any given time. Our findings support the hypothesis that DNA damage labeled using TdT reflects neuronal vulnerability and cell loss associated with AD pathology, and that at least a portion of the cells labeled with this technique is undergoing apoptosis. Furthermore, in agreement with in vitro findings, these results suggest a relationship between the expression of c-Jun and neuronal risk and/or cell death in AD.

Aged↗