Parathyroid cells express dihydropyridine-sensitive cation currents and L-type calcium channel subunits

Parathyroid cells express Ca2+-conducting currents that are activated by raising the extracellular Ca2+ concentration ([Ca2+]o). We investigated the sensitivity of these currents to dihydropyridines, the expression of voltage-dependent Ca2+ channel (VDCC) subunits, and the effects of dihydropyridines on the intracellular free [Ca2+] ([Ca2+]i) and secretion in these cells. Dihydropyridine channel antagonists dose dependently suppressed Ca2+-conducting currents, and agonists partially reversed the inhibitory effects of the antagonists in these cells. From a bovine parathyroid cDNA library, we isolated cDNA fragments encoding parts of an α1S- and a β3-subunit of L-type Ca2+ channels. The α1S-subunit cDNA from the parathyroid represents an alternatively spliced variant lacking exon 29 of the corresponding gene. Northern blot analysis and immunocytochemistry confirmed the presence of transcripts and proteins for α1- and β3-subunits in the parathyroid gland. The addition of dihydropyridines had no significant effects on high [Ca2+]o-induced changes in [Ca2+]i and parathyroid hormone (PTH) release. Thus our studies indicate that parathyroid cells express alternatively spliced L-type Ca2+ channel subunits, which do not modulate acute intracellular Ca2+ responses or changes in PTH release.

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Possible role of calcium in parathyroid hormone actions in rabbit renal proximal tubules

AJP Renal Physiology ◽

10.1152/ajprenal.1986.250.5.f942 ◽

1986 ◽

Vol 250 (5) ◽

pp. F942-F948

Author(s):

N. Yanagawa ◽

O. D. Jo

Keyword(s):

Parathyroid Hormone ◽

Proximal Tubules ◽

Inhibitory Effects ◽

Renal Proximal Tubules ◽

Intracellular Ca ◽

Altered Response ◽

Isolated Renal Tubule ◽

Convoluted Tubules

Using a glucose microassay and in vitro isolated renal tubule perfusion technique, we have studied the actions of parathyroid hormone (PTH) on gluconeogenesis (GNG) and fluid (Jv) and phosphate (Jp) transport rates in isolated rabbit renal proximal tubules. In proximal straight tubules (PST), PTH stimulated GNG and inhibited Jv and Jp. In proximal convoluted tubules (PCT), PTH inhibited Jv but failed to affect GNG and Jp. An increase in Ca concentration, however, stimulated GNG and allowed PTH to inhibit Jp in PCT. Addition of the intracellular Ca antagonists trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) abolished the inhibitory effects of PTH on Jv and Jp in both PCT and PST. In conclusion, these studies suggest that Ca-dependent intracellular pathways may be involved in the actions of PTH in rabbit renal proximal tubules. The altered response to PTH in rabbit PCT may be due to alterations in the response of intracellular Ca to the hormone.

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Role of Ca2+ in injury-induced changes in sodium current in rat skeletal muscle

AJP Cell Physiology ◽

10.1152/ajpcell.00021.2009 ◽

2009 ◽

Vol 297 (2) ◽

pp. C352-C359 ◽

Cited By ~ 5

Author(s):

Gregory N. Filatov ◽

Martin J. Pinter ◽

Mark M. Rich

Keyword(s):

Voltage Dependence ◽

Sodium Current ◽

Muscle Fibers ◽

Current Amplitude ◽

Resting Potential ◽

Fast Inactivation ◽

Adult Rat ◽

Voltage Dependent ◽

Intracellular Ca ◽

Induced Changes

Characteristics of voltage-dependent sodium current recorded from adult rat muscle fibers in loose patch mode were rapidly altered following nearby impalement with a microelectrode. Hyperpolarized shifts in the voltage dependence of activation and fast inactivation occurred within minutes. In addition, the amplitude of the maximal sodium current decreased within 30 min of impalement. Impalement triggered a sustained elevation of intracellular Ca2+. However, buffering Ca2+ by loading fibers with AM-BAPTA did not affect the hyperpolarized shifts in activation and inactivation, although it did prevent the reduction in current amplitude. Surprisingly, the rise in intracellular Ca2+ occurred even in the absence of extracellular Ca2+. This result indicated that the injury-induced Ca2+ increase came from an intracellular source, but it was not blocked by an inhibitor of release from the sarcoplasmic reticulum, which suggested involvement of mitochondria. Ca2+ release from mitochondria triggered by carbonyl cyanide 3-chlorophenylhydrazone was sufficient to cause a reduction in sodium current amplitude but had little effect of the voltage dependence of activation and fast inactivation. Our data suggest the effects of muscle injury can be separated into a Ca2+-dependent reduction in amplitude and a largely Ca2+-independent shift in activation and fast inactivation. Together, the impalement-induced changes in sodium current reduce the number of sodium channels available to open at the resting potential and may limit further depolarization and thus promote survival of muscle fibers following injury.

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Interaction between amrinone and parathyroid hormone on bone in culture

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1982.243.6.e499 ◽

1982 ◽

Vol 243 (6) ◽

pp. E499-E504

Author(s):

N. S. Krieger ◽

P. H. Stern

Keyword(s):

Parathyroid Hormone ◽

Bone Resorption ◽

Direct Interaction ◽

Inhibitory Effects ◽

Dihydroxyvitamin D3 ◽

Basal Bone ◽

Cardiotonic Agent ◽

Neonatal Mouse Calvaria ◽

Dose Dependent ◽

Stimulation Of

The cardiotonic agent amrinone has been postulated to directly affect Na-Ca exchange. Because stimulated bone resorption has been proposed to require Na-Ca exchange, we examined the effects of amrinone on bone. Amrinone inhibited release of Ca from neonatal mouse calvaria in organ culture stimulated by parathyroid hormone (PTH), 1,25-dihydroxyvitamin d3, or prostaglandin E2. Inhibition was dose dependent and maximal at 2 X 10(-4) M. The effect of amrinone differed from the inhibitory effects of calcitonin, ouabain, or nigericin in that 1) 6-h exposure to amrinone alone prevented the effect of subsequently added PTH; 2) amrinone was only partially effective if added after resorption was initiated by 24-h treatment with PTH; 3) coincubation with amrinone and PTH during the first 48 h of culture allowed for a response to PTH after amrinone was removed; no such protection by a stimulator occurred with ouabain or nigericin. Also submaximal concentrations of amrinone plus calcitonin, ouabain, or nigericin gave greater than additive inhibition of Ca release. Amrinone had no effect on basal bone cAMP or on the acute stimulation of cAMP by PTH. The results suggest that amrinone could have a more direct interaction with the pathway involved in stimulated bone resorption than the other inhibitors.

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Northern Blot Analysis of microRNAs and Other Small RNAs in Plants

Methods in Molecular Biology - Plant MicroRNAs ◽

10.1007/978-1-4939-9042-9_9 ◽

2019 ◽

pp. 121-129 ◽

Cited By ~ 1

Author(s):

Carlos De la Rosa ◽

José Luis Reyes

Keyword(s):

Northern Blot ◽

Blot Analysis ◽

Small Rnas ◽

Northern Blot Analysis

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Application of biotinylated oligonucleotide probes to the detection of pituitary hormone mRNA using Northern blot analysis, in situ hybridization at the light- and electron-microscope levels

The Histochemical Journal ◽

10.1007/bf00188075 ◽

1994 ◽

Vol 26 (10) ◽

pp. 771-777 ◽

Cited By ~ 1

Author(s):

Akira Matsuno ◽

Akira Teramoto ◽

Susumu Takekoshi ◽

Hirotoshi Utsunomiya ◽

Yoshitaka Ohsugi ◽

...

Keyword(s):

In Situ Hybridization ◽

Electron Microscope ◽

Northern Blot ◽

Blot Analysis ◽

Northern Blot Analysis ◽

Pituitary Hormone ◽

Oligonucleotide Probes

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IL-8 and MCP Gene Expression and Production by LPS-Stimulated Human Corneal Stromal Cells

International Journal of Inflammation ◽

10.1155/2012/714704 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

Roni M. Shtein ◽

Susan G. Elner ◽

Zong-Mei Bian ◽

Victor M. Elner

Keyword(s):

Gene Expression ◽

Northern Blot ◽

Stromal Cells ◽

Blot Analysis ◽

Time Course ◽

Northern Blot Analysis ◽

Statistical Significance ◽

Dependent Manner ◽

Corneal Inflammation ◽

Chemotactic Protein

Purpose. To determine time course of effect of lipopolysaccharide (LPS) on production of interleukin-8 (IL-8) and monocyte chemotactic protein (MCP) by cultured human corneal stromal cells.Methods. Human corneal stromal cells were harvested from donor corneal specimens, and fourth to sixth passaged cells were used. Cell cultures were stimulated with LPS for 2, 4, 8, and 24 hours. Northern blot analysis of IL-8 and MCP gene expression and ELISA for IL-8 and MCP secretion were performed. ELISA results were analyzed for statistical significance using two-tailed Student'st-test.Results. Northern blot analysis demonstrated significantly increased IL-8 and MCP gene expression after 4 and 8 hours of exposure to LPS. ELISA for secreted IL-8 and MCP demonstrated statistically significant increases (P<0.05) after corneal stromal cell stimulation with LPS.Conclusions. This paper suggests that human corneal stromal cells may participate in corneal inflammation by secreting potent leukocyte chemotactic and activating proteins in a time-dependent manner when exposed to LPS.

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Purification and characterization of the plasminogen activator inhibitors PAI-1, PAI-2, and PN-1 from the human glioblastoma U138

Biochemistry and Cell Biology ◽

10.1139/o93-038 ◽

1993 ◽

Vol 71 (5-6) ◽

pp. 248-254 ◽

Cited By ~ 2

Author(s):

Patricia G. Murphy ◽

Steven P. Lenz ◽

Mark Dobson ◽

Allan D. Arndt ◽

David A. Hart

Keyword(s):

Monoclonal Antibody ◽

Plasminogen Activator ◽

Concanavalin A ◽

Northern Blot ◽

Northern Blot Analysis ◽

Plasminogen Activator Inhibitor ◽

Immunoaffinity Column ◽

Positive Hybridization ◽

Activator Inhibitor ◽

Pai 1

This investigation presents data which indicate that the plasminogen activator inhibitor (PAI) activity secreted from U138 cells is composed of three separate PAIs: PAI-1, PAI-2, and PN-1. It was demonstrated that the U138 PAI-1-like protein had an apparent molecular mass of 50 kilodaltons (kDa) and was purified to apparent homogeneity by elution from an anti-PAI-1 immunoaffinity column. These fractions were also reactive with a second anti-PAI-1 monoclonal antibody using immunoblotting techniques. Northern blot analysis of RNA isolated from unstimulated U138 cells demonstrated positive hybridization with the cDNA specific for human PAI-1. The U138 PAI-2-like protein was adherent to an anti-PAI-2 immunoaffinity column and was demonstrated to be nonadherent to concanavalin A – agarose, heparin–Sepharose, and the anti-PAI-1 immunoaffinity column. The eluted U138 PAI-2-like protein was demonstrated to have an apparent molecular mass of 60 kDa and was also reactive with a second anti-PAI-2 monoclonal antibody using immunoblotting techniques. Further, the cDNA specific for PAI-2 was demonstrated to hybridize to a 2.5-kilobase message from RNA isolated from U138 cells. A third PAI was detected that was nonadherent to concanavalin A – agarose and both of the anti-PAI columns. This 50-kDa PAI was adherent to heparin–Sepharose and thrombin–agarose columns, and was not reactive with any antibodies for either PAI-1 or PAI-2. Northern blot analysis of U138 RNA demonstrated positive hybridization with an oligodeoxynucleotide specific for PN-1. This investigation demonstrates with biochemical, immunological, and molecular data that the U138 glioblastoma constitutively produces three PAIs.Key words: plasminogen activator inhibitor, U138 glioblastoma, PAI purification, human tumor cell line, proteinase inhibitors.

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