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At least 955 records · Page 53Linked to original sources

PubMed2005

Nitric oxide synthase in the gill of Atlantic salmon: colocalization with and inhibition of Na+,K+-ATPase.

We investigated the relationship between nitric oxide (NO) and Na(+),K(+)-ATPase (NKA) in the gill of anadromous Atlantic salmon. Cells containing NO-producing enzymes were revealed by means of nitric oxide synthase (NOS) immunocytochemistry and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry, which can be used as an indicator of NOS activity, i.e. NO production. Antibodies against the two constitutive NOS isoforms, neuronal and endothelial NOS, both produced immunoreactivity restricted to large cells at the base and along the secondary lamellae. NADPHd-positive cells showed a corresponding distribution. Antibodies against the inducible NOS isoform only labeled small cells located deep in the filament. Using in situ hybridization and NKA immunoreactivity, cells expressing Na(+),K(+)-ATPase alpha-subunit mRNA were found to have a similar distribution to the NOS cells. Double labeling for NOS immunoreactivity and NKA alpha-subunit mRNA revealed cellular colocalization of NKA alpha-subunit mRNA and nNOS protein in putative chloride cells at the base of the lamellae and interlamellar space. Along the lamellae, some NOS- or NKA-immunoreactive cells possessed a relatively lower expression of NKA alpha-subunit mRNA in smolts. A clear increase in NADPHd staining in the gill was demonstrated from parr to smolt. The regulatory role of NO on gill NKA activity was studied in vitro using sodium nitroprusside (SNP; 1 mmol l(-1)) and PAPA-NONOate (NOC-15; 0.5 mmol l(-1)) as NO donors. Both SNP and NOC-15 inhibited gill NKA activity by 30% when compared to controls. The study shows that NO systems are abundant in the gill of Atlantic salmon, that NO may be produced preferentially by a constitutive NOS isoform, and suggests that NO influence on gill functions is mediated via intracellular, possibly both auto/paracrine, inhibition of Na(+),K(+)-ATPase activity in chloride cells. Furthermore, the increase in NADPHd in the gill during smoltification suggests a regulatory role of NO in the attenuation of the smoltification-related increase in Na(+),K(+)-ATPase activity prior to entering seawater.

Animals↗

PubMed2003

The GW182 protein colocalizes with mRNA degradation associated proteins hDcp1 and hLSm4 in cytoplasmic GW bodies.

A novel cytoplasmic compartment referred to as GW bodies (GWBs) was initially identified using antibodies specific to a 182-kD protein termed GW182. GW182 was characterized by multiple glycine(G)-tryptophan(W) repeats and an RNA recognition motif (RRM) that bound a subset of HeLa cell messenger RNAs (mRNAs). The function of GWBs was not known; however, more recent evidence suggested similarities between GWBs and cytoplasmic structures that contain hLSm proteins and hDcp1, the human homolog to a yeast decapping enzyme subunit. In this study, we used antibodies to hLSm4 and hDcp1 to show that both of these markers of an mRNA degradation pathway colocalize to the same structures as GW182. Our studies demonstrate that GW182, hLSm4, and hDcp1 are found in the same cytoplasmic structures and suggest that GW182 is involved in the same mRNA processing pathway as hLSm4 and hDcp1.

Autoantigens↗

PubMed1994

Immunohistochemical colocalization of serotonin, aromatic L-amino acid decarboxylase and polypeptide hormones in islet A- and PP-cells of the cat pancreas.

To establish which monoamines are elaborated in the pancreatic islet cells of cats, the pancreatic tissue was studied by immunohistochemistry on serial or mirror tissue sections. Glucagon-containing A-cells reacted immunohistochemically with antisera directed against serotonin and aromatic L-amino acid decarboxylase, though the half of A-cells immunostained with glucagon antiserum did not show the colocalization with serotonin. Pancreatic polypeptide-containing PP-cells also showed immunoreactivity for antisera directed against serotonin and aromatic L-amino acid decarboxylase. However, PP-cells exhibiting immunoreactivity for serotonin were very few in number. The overlapping areas of the two types of cell represented only a small proportion of the PP-cells. Immunoreactivity for aromatic L-amino acid decarboxylase was observed within almost all A- and PP-cells. Since aromatic L-amino acid decarboxylase is an enzyme involved in the synthesis of serotonin, it is concluded that pancreatic islet A- and PP-cells in cats have the ability to elaborate serotonin. Contrarily, islet B- and D-cells showing immunoreactivity for insulin and somatostatin antisera, respectively, did not react with antisera directed against serotonin and aromatic L-amino acid decarboxylase.

Animals↗

PubMed1999

Colocalization of gamma-aminobutyric acid immunoreactivity and acetylcholinesterase activity in nerve fibers of the mouse adrenal gland.

The present immunohistochemical and enzyme histochemical study showed gamma-aminobutyric acid (GABA) immunoreactivity and acetylcholinesterase (AChE) activity in the mouse adrenal gland. Weak GABA immunoreactivity was seen in clusters of chromaffin cells showing noradrenaline fluorescence. This finding suggests that both GABA and noradrenaline may be released from the granules of noradrenaline cells by adequate stimuli. GABA-immunoreactive varicose nerve fibers densely contacted adrenaline cells and large ganglion cells, but they were sparse in the periphery of clusters of noradrenaline cells. AChE activity was strong in a few large ganglion cells and weak in chromaffin cells showing noradrenaline fluorescence, and was found in numerous nerve bundles and fibers of the medulla. AChE-active nerve fibers more densely contacted noradrenaline cells than adrenaline cells. By using double labeling technique, numerous GABA-immunoreactive nerve fibers in the medulla were reactive for AChE in the same sections. These results suggest that both GABA and acetylcholine may be colocalized in the intra-adrenal nerve fibers and may have some secretory effects on the chromaffin cells.

Acetylcholinesterase↗

PubMed2005

Mosquito phenoloxidase and defensin colocalize in melanization innate immune responses.

Mosquitoes mount strong humoral and cellular immune responses against foreign organisms. Two components of the mosquito immune response that have received much attention are the phenoloxidase cascade that leads to melanization and antimicrobial peptides. The purpose of the current study was to use immunocytochemistry and transmission electron microscopy to identify the location of the melanization rate-limiting enzyme phenoloxidase and the antimicrobial peptide defensin in innate immune reactions against Escherichia coli and Micrococcus luteus by the mosquito Aedes aegypti. Our results show that both phenoloxidase and defensin are present at the sites of melanin biosynthesis in immune reactions against bacteria. Furthermore, both proteins are often present inside the same melanotic capsules. When hemocytes were analyzed, phenoloxidase was present in the cytosol of oenocytoids, but no significant amounts of defensin were detected inside any hemocytes. In summary, these data show that phenoloxidase and defensin colocalize in melanization reactions against bacteria and argue for further studies into the potential role of defensin in phenoloxidase-based melanization innate immune responses in mosquitoes.

Aedes↗

PubMed2003

Pituitary adenylate cyclase-activating polypeptide does not colocalize with vasoactive intestinal polypeptide in the hypothalamic magnocellular nuclei and posterior pituitary of cats and rats.

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) immunoreactive cells were demonstrated in the hypothalamic magnocellular nuclei in cats and rats. In cats these immunoreactive cells were stained without any treatment or intervention; however, in rats we had to use the pituitary stalk section to enhance the amount of PACAP and VIP for successful immunostaining. In both species the regions occupied by PACAP and VIP immunoreactive cells partially overlap each other in the paraventricular and supraoptic nuclei. Nevertheless, in either cats or rats PACAP and VIP immunoreactivities do not colocalize in the same cells studied by double labeling immunohistochemistry (IHC) or by the combination of immunohistochemistry and in situ hybridization. As was expected, PACAP and VIP immunoreactive materials were stored in different fibers of the posterior pituitary where the distribution of PACAP and VIP fibers also showed different patterns: PACAP fibers form a dense plexus at the periphery of the posterior lobe, in the vicinity of the intermediate lobe; however, the VIP fibers were evenly distributed mainly in the center of the posterior lobe. In spite of the high sequence homology of PACAP and VIP, the two peptides are synthesized in different subpopulations of hypothalamic neurons. This different distribution correlates well with the different role of the hypothalamic PACAP and VIP in the biologic clock and in the functions of the anterior and posterior pituitary.

Animals↗

PubMed1998

Colocalization of tumor necrosis factor-alpha and nitric oxide-synthase immunoreactivity in mast cell granules of nasal mucosa.

We have demonstrated, with immunohistochemical techniques, the colocalization of tumour necrosis factor-alpha (TNF alpha) with a constitutive neuronal isoform of nitric oxide-synthase (NOS) in granules of the majority (52.77%) of the mast cells (MCs) of healthy human nasal mucosa. Very few cells were positive for NOS alone (2.54%). Some cells were positive for TNF alpha alone (16.73%) or negative for both antigens (18%). Since dim degranulation occurs in MCs of healthy nasal mucosa at any time, we propose that low concentrations of TNF alpha and NOS secreted by these cells are involved not only in the regulation of homeostasis of normal human nasal mucosa, but also in the survival and function of MCs themselves.

Adolescent↗

PubMed2004

Fibroblast growth factor homologous factor 2B: association with Nav1.6 and selective colocalization at nodes of Ranvier of dorsal root axons.

Voltage-gated sodium channels interact with cytosolic proteins that regulate channel trafficking and/or modulate the biophysical properties of the channels. Na(v)1.6 is heavily expressed at the nodes of Ranvier along adult CNS and PNS axons and along unmyelinated fibers in the PNS. In an initial yeast two-hybrid screen using the C terminus of Na(v)1.6 as a bait, we identified FHF2B, a member of the FGF homologous factor (FHF) subfamily, as an interacting partner of Na(v)1.6. Members of the FHF subfamily share approximately 70% sequence identity, and individual members demonstrate a cell- and tissue-specific expression pattern. FHF2 is abundantly expressed in the hippocampus and DRG neurons and colocalizes with Na(v)1.6 at mature nodes of Ranvier in myelinated sensory fibers in the dorsal root of the sciatic nerve. However, retinal ganglion cells and spinal ventral horn motor neurons show very low levels of FHF2 expression, and their axons exhibit no nodal FHF2 staining within the optic nerve and ventral root, respectively. Thus, FHF2 is selectively localized at nodes of dorsal root sensory but not ventral root motor axons. The coexpression of FHF2B and Na(v)1.6 in the DRG-derived cell line ND7/23 significantly increases the peak current amplitude and causes a 4 mV depolarizing shift of voltage-dependent inactivation of the channel. The preferential expression of FHF2B in sensory neurons may provide a basis for physiological differences in sodium currents that have been reported at the nodes of Ranvier in sensory versus motor axons.

Animals↗

PubMed2005

D2 dopamine receptors colocalize regulator of G-protein signaling 9-2 (RGS9-2) via the RGS9 DEP domain, and RGS9 knock-out mice develop dyskinesias associated with dopamine pathways.

Regulator of G-protein signaling 9-2 (RGS9-2), a member of the RGS family of G GTPase accelerating proteins, is expressed specifically in the striatum, which participates in antipsychotic-induced tardive dyskinesia and in levodopa-induced dyskinesia. We report that RGS9 knock-out mice develop abnormal involuntary movements when inhibition of dopaminergic transmission is followed by activation of D2-like dopamine receptors (DRs). These abnormal movements resemble drug-induced dyskinesia more closely than other rodent models. Recordings from striatal neurons of these mice establish that activation of D2-like DRs abnormally inhibits glutamate-elicited currents. We show that RGS9-2, via its DEP domain (for Disheveled, EGL-10, Pleckstrin homology), colocalizes with D2DRs when coexpressed in mammalian cells. Recordings from oocytes coexpressing D2DR or the m2 muscarinic receptor and G-protein-gated inward rectifier potassium channels show that RGS9-2, via its DEP domain, preferentially accelerates the termination of D2DR signals. Thus, alterations in RGS9-2 may be a key factor in the pathway leading from D2DRs to the side effects associated with the treatment both of psychoses and Parkinson's disease.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1996

Colocalization of connexin 43 and connexin 45 but absence of connexin 40 in granulosa cell gap junctions of rat ovary.

The expression and localization of gap junction family proteins (connexins) were examined in nonstimulated and gonadotrophin-stimulated ovarian follicles of immature rats. Immunoblot and RNA blot analysis showed the presence of connexin (Cx) 43, Cx40 and Cx45 in ovarian tissue. Of these connexin proteins, Cx43 and Cx45 were identified by immunofluorescent microscopy between granulosa cells in characteristic expression patterns related to follicular developmental stages, while Cx40 was not expressed in granulosa cells but was detected in blood vessels in ovarian stroma. In some plaques of gap junction between granulosa cells, Cx45 was found to be colocalized with Cx43. In immunofluorescent microscopy, the expression of Cx43 was increased with follicular growth, but decreased after induction of ovulation by injection of human chorionic gonadotrophin. In contrast, the Cx45 protein was constantly expressed through follicular development; however, after ovulation, no staining of Cx45 was detected in the corpus luteum. Dual expression and the functional role of Cx43 and Cx45 in cell-to-cell communication in ovarian granulosa cells at various developmental stages were discussed.

Animals↗

PubMed2003

Colocalization analysis of sialomucins CD34 and CD164.

Flow cytometric protocols are employed to identify and characterize hemopoietic stem/progenitor populations before transplantation. Cell surface antigens, including CD34, are employed in this process and widely used in harvest protocols, which largely ignores the potential functional role of such antigens. Transmembrane glycoprotein sialomucins, including CD34 and CD164, have been implicated in cell-to-cell interactions and activation. CD164, also expressed on early hemopoietic populations, was reported to have a possible function facilitating CD34(+) cells to adhere to bone marrow stroma. In this study, we employed high-definition laser-scanning confocal microscopy to investigate CD34 and CD164 surface co-localization patterns on bone marrow and cord blood cells and to compare the expression patterns using a three-dimensional computer-generated method developed in house. Differential interference microscopy analysis revealed bone marrow membrane activity was higher than the corresponding cord blood counterpart, perhaps indicating the marrow microenvironmental nature. Fluorescence analysis of CD34 and CD164 antigens showed both were expressed first in a halo-like pattern and second in antigen-dense pockets. Three-dimensional computer analyses further revealed that this pocketing corresponded to dense crest-like surface structures appearing to rise from the point of adherence on the slide. Further, it was found that CD34 and CD164 display strong colocalization patterns on cells expressing both antigens. The dual nature of the CD34 and CD164 antigens discovered here lends further evidence to the previous literature implicating a strong functional link between these two sialomucins, which should be considered in the transplantation arena and in the function of such sialomucins as negative regulators of cell proliferation.

Antigens, CD34↗

PubMed1994

Insulin-induced hypoglycaemia increases colocalization of corticotrophin-releasing factor and arginine vasopressin mRNAs in the rat hypothalamic paraventricular nucleus.

The regulation of ACTH secretion during stress is a multifactorial process that mainly involves two hypothalamic neurohormones: corticotrophin-releasing factor (CRF) and arginine vasopressin (AVP). In this report we measured, using semiquantitative in situ hybridization, the concentrations of CRF and AVP mRNA in hypophyseotrophic paraventricular parvocellular cell bodies of male rats after an acute (3-h) exposure to insulin-induced hypoglycaemia. Insulin injection (2.5 IU/kg) induced a significant decrease in blood glucose levels and a strong increase in plasma ACTH concentrations. The concentration of CRF mRNA in the paraventricular nucleus (PVN) was significantly increased after insulin-induced hypoglycaemia (150% of control levels), while the number of CRF mRNA-containing cell bodies was not changed. Double-labelling experiments demonstrated that the number of CRF mRNA-containing cell bodies that also contained AVP mRNA was doubled after insulin injection. These data demonstrate that the established increased colocalization of AVP immunoreactivity in nerve terminals immunoreactive for CRF after exposure to stress follows a pretranslational activation of AVP synthesis. Cell-by-cell analysis indicated that the mean CRF hybridization signal was increased in double-labelled cells (about 150% of control levels), suggesting that the increase in CRF gene expression occurs equally in the AVP-synthesizing and in the AVP-deficient CRF mRNA-containing cell bodies. The mean AVP hybridization signal in the double-labelled cells was decreased, suggesting that the amount of AVP mRNA was unchanged in the cell bodies that expressed both CRF and AVP in the basal state and that AVP mRNA levels in the cell bodies recruited after insulin-induced hypoglycaemia were below control values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

PubMed2000

Nuclear colocalization and complex formation of insulin with retinoblastoma protein in HepG2 human hepatoma cells.

Previous structural and biochemical evidence had suggested that insulin may bind to the nuclear tumor suppressor retinoblastoma protein (RB). The present study is now the first to unravel the physical and functional interaction between a growth factor and an anti-oncoprotein, specifically demonstrating the association between insulin and RB in living cells and finding that this complex formation is relevant for cell division. Our immunofluorescence microscopy data suggest that insulin colocalizes with RB in the cell nuclei of HepG2 human hepatoma cells and that contacts the B-region of the RB pocket. Furthermore, these events were found to correlate with an enhancement of cell proliferation. These results are in line with the initial structure-based predictions and, moreover, provide a suitable starting point for the further understanding as well as the pharmacological modulation of nucleocrine interactions between growth factors and tumor suppressors, in physiology and disease.

Antibodies, Monoclonal↗

PubMed1993

Colocalization of GABA-immunoreactivity in neuropeptide- and monoamine-containing amacrine cells in the retina of Bufo marinus.

Immunocytochemical study was performed in the Bufo marinus retina to reveal the localization of gamma-aminobutyric acid (GABA)-immunoreactivity in neuropeptide Y (NPY)-, substance P (SP)-, serotonin (5HT)-and tyrosine hydroxylase (TH)-immunoreactive amacrine cells. GABA-immunoreactivity was present in all NPY-, in some of the SP- and 5HT-containing amacrine cells, but not in TH-immunoreactive amacrine cells. Among the 5HT-immunoreactive amacrine cells, a population of 5HT-synthesizing and most of the 5HT-accumulating cells were GABA-immunoreactive. These results indicate that neuropeptide- and GABA-immunoreactivity are colocalized in amacrine cells of the anuran retina. We propose a possible co-transmission for two classical neurotransmitters (GABA and 5HT) in some of the 5HT-containing amacrine cells.

Animals↗

PubMed1994

NADPH-diaphorase is colocalized with nitric oxide synthase and vasoactive intestinal polypeptide in rat pancreatic neurons in culture.

NADPH-diaphorase activity together with nitric oxide synthase- and vasoactive intestinal polypeptide-immunoreactivities were examined in the neurons of the rat pancreas in culture. Nitric oxide synthase (NOS)- and vasoactive intestinal polypeptide (VIP)-immunoreactivities were localized in a subpopulation of neurons which were also NADPH-diaphorase positive. All neurons expressing colocalized activities for NOS/VIP and NADPH-diaphorase were solitary cells in culture. Each of these double-labelled neurons was characterized by a round or oval cell body, with short and long processes emanating from it. Some of these processes traversed several micrometres before terminating on the exocrine acinar and endocrine cells. The present study provides evidence that nitric oxide may act as a regulatory agent in the inhibitory neural control of the secretory functions in the pancreas, thereby maintaining the milieu interieur of the organism.

Amino Acid Oxidoreductases↗

PubMed1994

Immunohistochemical distribution of 7B2 and colocalization with calcitonin gene-related peptide in rat lung.

The novel pituitary protein 7B2 has a widespread distribution in neurons and paraneurons and is known to be associated with endocrine disorders. In the mammalian lung, solitary neuroendocrine cells (NECs) and their innervated aggregates, termed neuroepithelial bodies (NEBs), are scattered along the bronchopulmonary tree; however, presence of 7B2 in these structures has not previously been reported. Bouin fixed, paraffin embedded rat lungs were cut and stained for 7B2, using a polyclonal antibody and a streptavidin biotin immunoperoxidase method. The identity of NEBs was confirmed on adjacent serial sections by the immunocytochemical reaction for calcitonin gene-related peptide (CGRP). NEBs selectively labelled for 7B2 are distributed throughout bronchi, bronchioli and alveolar ducts, whereas NECs are always negative. Likewise, 7B2 immunoreactivity is not detected in intrapulmonary ganglion cells nor in nerve fibers. Immunoreactivity for CGRP, on the other hand, occurs in NECs, NEBs, nerve fibers and neuronal somata. Colocalization of both peptides is demonstrated in almost all NEBs. This study presents the first immunohistochemical demonstration and morphological mapping of 7B2 in the rat lung. The finding that only NEBs are stained suggests biochemical and functional variations between NEBs and NECs as well as the absence of a role for 7B2 in the pulmonary nervous system.

Animals↗

PubMed1995

Colocalization of H-ATPase and H,K-ATPase immunoreactivity in the rat kidney.

Urinary acidification in the collecting duct (CD) is via V-type H-ATPase and P-type H,K-ATPase. The localization and polar distribution of H-ATPase in intercalated cells (IC) have been well studied. The localization of H,K-ATPase to IC has been reported, but its intracellular distribution has not been defined. To colocalize these pumps, a murine monoclonal antibody (E11) to the 31-kd subunit of the H-ATPase and a rabbit antiserum (HK alpha N2) to a synthetic peptide based on the N terminus of the hog gastric H,K-ATPase alpha-subunit were used. In immunocytochemical staining of rat kidney, H,K-ATPase was present only in the IC of the CD with the same polar distribution as H-ATPase. The preabsorption of HK alpha N2 with affinity-purified bovine H-ATPase did not affect the H,K-ATPase staining, whereas preabsorption with the immunizing synthetic peptide eliminated immunoreactivity. HK alpha N2 stained only parietal cells in the rat gastric mucosa, whereas preimmune serum and E11 showed no immunoreactivity. On immunoblots of rat gastric mucosal microsomes, HK alpha N2 labeled a single 94-kd band, and this staining disappeared after preabsorption with the immunizing synthetic peptide. HK alpha N2 labeled no bands on immunoblots of affinity-purified bovine H-ATPase. All immunochemistry was negative with preimmune serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2000

Acoustic schwannoma and arachnoid cyst colocated in the cerebellopontine angle--case report.

A 50-year-old female presented with a right acoustic schwannoma colocated with a cerebellopontine angle arachnoid cyst. The arachnoid cyst was distinct from the arachnoid cap surrounding the acoustic schwannoma. Initial excision of the arachnoid cyst created the space required to excise the schwannoma. The acoustic schwannoma had surprisingly dense adhesions to the brainstem, probably due to the constant pressure exerted by the cyst displacing the tumor towards the brainstem. The acoustic schwannoma was excised by meticulous dissection. Such a coexisting lesion should be suspected when a large cystic collection surrounds an acoustic schwannoma. Initial excision of the arachnoid cyst will prevent excessive cerebellar retraction.

Arachnoid Cysts↗