Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Arginine vasopressin (AVP) induced concentration-dependent (10(-9) to 10(-6) M) stimulation of inositol phosphate production and a biphasic increment of cytosolic free Ca2+ concentration ([Ca2+]i) in skeletal myogenic cells in culture. These effects were almost completely abolished when the cells were pretreated with the AVP antagonist [deamino-Pen1,Val4,D-Arg8]-vasopressin before stimulation with AVP, thus confirming a V1 receptor-mediated effect. Inositol 1,4,5-trisphosphate production was maximally stimulated within 2-3 s of treatment with AVP, immediately followed by release of Ca2+ from intracellular deposits. Both effects were inhibited by treatment with 12-O-tetradecanoyl phorbol 13-acetate (TPA). Such effect of TPA was reversed by the protein kinase C inhibitor staurosporine. Vasopressin also regulated the intracellular pH of responsive cells with mechanisms involving both Na+ and anion transport across the plasma membrane. However, unlike in other cell types, AVP stimulated the Na(+)-H+ antiport only simultaneously with a dramatic cell acidification or after treatment with TPA. Response to AVP was observed in L6 and L5 and, to a lesser extent, in chick embryo myogenic cells, regardless of the stage of differentiation (myoblast or myotube). Comparison of different subclones of the L6 cell line demonstrated that the responsiveness to AVP correlated positively with their myogenic potential.
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PMID:Transduction of arginine vasopressin signal in skeletal myogenic cells. 839 77

Results presented in this study demonstrate that, in rat glomerulosa cells, fluoroaluminate (AlF4-) alone stimulates both cAMP accumulation (maximal stimulation 10-fold, ED50, 24 mM) and total inositol phosphate accumulation (maximal stimulation 12-fold, ED50 14 mM). Despite a transient accumulation of Ins(1,4,5)P3 after AlF4- stimulation, no rapid and transient intracellular calcium mobilization was observed. In contrast to angiotensin II (Ang II) or vasopressin (AVP), AlF4- induces only a slow and sustained increase in intracellular Ca2+. We demonstrate that this increase results from a Ca2+ influx mediated by cAMP-protein kinase A (PKA) pathway since preincubation with H-89, a potent PKA inhibitor, inhibits this influx. Moreover, a short preincubation (15 min at 37 degrees C) of cells with AlF4- or ACTH prevents the initial release of Ca2+ from intracellular stores induced by Ang II, but does not affect the amount of InsPs accumulated under Ang II stimulation. This rapid inhibition of Ang II action is mediated by ACTH- or AlF4(-)-stimulated cAMP production since pretreatment with H-89 leads to a complete reversal. cAMP most likely acts at the level of Ins(1,4,5)P3 receptors since an increase in intracellular cAMP blunts the calcium response induced by addition of exogenous Ins(1,4,5)P3 to permeabilized cells. These results point out that, in rat glomerulosa cells, activation of the cAMP pathway can induce a rapid desensitization of the phospholipase C pathway by acting downstream of inositol phosphate accumulation.
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PMID:Dual effects of fluoroaluminate on activation of calcium influx and inhibition of agonist-induced calcium mobilization in rat glomerulosa cells. 865 54

We tested the hypothesis that ethanol impairs liver regeneration by abrogating receptor-mediated elevation of cytosolic free calcium ([Ca2+]i). In rats fed for 16 weeks with ethanol, hepatocellular proliferation induced by partial hepatectomy was greatly impaired. Similarly, EGF-induced DNA synthesis was reduced in cultured hepatocytes from ethanol-fed rats. There was no change in the number or affinity of EGF receptors on hepatocytes from ethanol-fed rats. Despite this, EGF-mediated production of inositol 1,4,5-trisphosphate (Ins[1,4,5]P3) was lower in hepatocytes from ethanol-fed rats, and the EGF-induced [Ca2+]i transient appeared to be abrogated. When vasopressin or phenylephrine were used as cell surface receptor ligands, hepatocytes cultured from ethanol-fed rats exhibited major reductions in Ins(1,4,5)P3 synthesis. This was associated with greatly truncated [Ca2+]i transients. These changes were not due to an effect on the Ins(1,4,5)P3 receptor on the endoplasmic reticulum or to a decrease in the size of the Ins(1,4,5)P3-mobilizable intracellular Ca+2 store. Further, mobilization of the same Ca2+ store by 2,5-di-tert-butylhydroquinone or thapsigargin restored the ability of hepatocytes from ethanol-fed rats to proliferate when exposed to EGF. It is concluded that chronic ethanol consumption inhibits liver regeneration by a mechanism that is, at least partly, the result of impaired receptor-operated [Ca2+]i signaling due to reduced generation of Ins(1,4,5)P3.
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PMID:Chronic ethanol administration to rats decreases receptor-operated mobilization of intracellular ionic calcium in cultured hepatocytes and inhibits 1,4,5-inositol trisphosphate production: relevance to impaired liver regeneration. 878 87

Arg8-vasopressin (AVP) is a potent inducer of myogenic differentiation stimulating the expression of myogenic regulatory factors. To understand the mechanism of its effect on myogenesis, we investigated the early signals induced by AVP in myogenic target cells. In the rat skeletal muscle cell line L6, AVP selectively stimulates phosphatidylinositol (PtdIns) and phosphatidylcholine (PtdCho) breakdown, through the activation of phospholipases C and D (PLC, PLD), as shown by the generation of Ins(1,4,5)P3 and phosphatidylethanol (PtdEtOH), respectively. AVP induces the biphasic increase of sn-1,2-diacylglycerol (DAG) consisting in a rapid peak followed by a sustained phase, and the monophasic generation of phosphatidic acid (PA). Propranolol (a PA phosphatase inhibitor) and Zn2+ (a PLD inhibitor), abolish the sustained phase of DAG generation. Our data indicate that PtdIns-PLC activity is mainly responsible for the rapid phase of AVP-dependent DAG generation, whereas the sustained phase is dependent upon PtdCho-PLD activity and PA dephosphorylation, ruling out any significant role of DAG kinase. Modifications of PA level correlate with parallel changes of PLC activity, indicating a possible cross-talk between the two signal transduction pathways in the intact cell. PLD activation is elicited at AVP concentrations two orders of magnitude lower than those required for PLC activation. The differentiation of L6 myoblasts into multinucleated fibers is stimulated significantly by AVP at concentrations at which PLD, but not PLC, is activated. These data provide the first evidence for an important role of PLD in the mechanism of AVP-induced muscle differentiation.
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PMID:Role of phospholipase C and D signalling pathways in vasopressin-dependent myogenic differentiation. 911 90

The roles of a monomeric GTP-binding regulatory protein in the activation of store-activated plasma membrane Ca2+ channels and in the release of Ca2+ from the smooth endoplasmic reticulum (SER) in rat liver parenchymal cells were investigated with the use of freshly isolated rat hepatocytes and rat liver microsomes. A low concentration (approx. 130 microM intracellular) of guanosine 5'-[gamma-thio]triphosphate (GTP[S]) activated Ca2+ inflow in intact hepatocytes in the absence of an agonist, whereas a high concentration (approx. 530 microM intracellular) of GTP-S- or guanosine 5'-[betagamma-imido]triphosphate (p[NH]ppG) inhibited the Ca2+ inflow induced by inhibitors of the activity of the endoplasmic-reticulum Ca2+-ATPase (SERCA) and by vasopressin. GTP (530 microM) prevented the inhibition of Ca2+ inflow by GTP-S- and p[NH]ppG. Brefeldin A and the peptide human Arf-1-(2-17), which inhibit many functions of ADP ribosylation factor (Arf) proteins, inhibited the Ca2+ inflow induced by SERCA inhibitors and vasopressin, and altered the profile of Ca2+ release from the SER. These effects were observed at concentrations of Brefeldin A and Arf-1-(2-17) comparable with those that inhibit the functions of Arf proteins in other systems. Succinylated Arf-1-(2-17) had a negligible effect on Ca2+ inflow. GTP[S] and Arf-1-(2-17) completely inhibited the synergistic action of GTP and Ins(1,4,5)P3 in releasing 45Ca2+ from rat liver microsomes loaded with 45Ca2+. AlF4(-) (under conditions expected to activate trimeric G-proteins) and succinylated Arf-1-(2-17) had no effect on GTP/Ins(1,4,5))3-induced 45Ca2+ release, and a mastoparan analogue caused partial inhibition. Arf-1-(2-17) did not inhibit 45Ca2+ release induced by either thapsigargin or ionomycin. It is concluded that a low-molecular-mass G-protein, most probably a member of the Arf protein family, is required for store-activated Ca2+ inflow in rat hepatocytes. The idea that the role of this G-protein is to maintain a region of the SER in the correct intracellular location is discussed briefly.
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PMID:Evidence that a low-molecular-mass GTP-binding protein is required for store-activated Ca2+ inflow in hepatocytes. 937 2

The roles of a subregion of the endoplasmic reticulum (ER) and the cortical actin cytoskeleton in the mechanisms by which Ins(1,4,5)P3 induces the activation of store-operated Ca2+ channels (SOCs) in isolated rat hepatocytes were investigated. Adenophostin A, a potent agonist at Ins(1,4,5)P3 receptors, induced ER Ca2+ release and the activation of Ca2+ inflow. The concentration of adenophostin A that gave half-maximal stimulation of Ca2+ inflow (10 nM) was substantially lower than that (20 nM) which gave half-maximal ER Ca2+ release. A low concentration of adenophostin A (approx. 13 nM) caused near-maximal stimulation of Ca2+ inflow but only 20% of maximal ER Ca2+ release. Similar results were obtained using another Ins(1,4,5)P3-receptor agonist, 2-hydroxyethyl-alpha-d-glucopyranoside 2,3',4'-trisphosphate. Anti-type-1 Ins(1,4,5)P3-receptor monoclonal antibody 18A10 inhibited vasopressin-stimulated Ca2+ inflow but had no observable effect on vasopressin-induced ER Ca2+ release. Treatment with cytochalasin B at a concentration that partially disrupted the cortical actin cytoskeleton inhibited Ca2+ inflow and ER Ca2+ release induced by vasopressin by 73 and 45%, respectively. However, it did not substantially affect Ca2+ inflow and ER Ca2+ release induced by thapsigargin or 13 nM adenophostin A, intracellular Ca2+ release induced by ionomycin or Ins(1,4, 5)P3P4(5)-1-(2-nitrophenyl)ethyl ester ['caged' Ins(1,4,5)P3] or basal Ca2+ inflow. 1-(5-Chloronaphthalene-1-sulphonyl)homopiperazine, HCl (ML-9), an inhibitor of myosin light-chain kinase, also inhibited vasopressin-induced Ca2+ inflow and ER Ca2+ release by 53 and 44%, respectively, but had little effect on thapsigargin-induced Ca2+ inflow and ER Ca2+ release. Neither cytochalasin B nor ML-9 inhibited vasopressin-induced Ins(1,4,5)P3 formation. It is concluded that the activation of SOCs in rat hepatocytes induced by Ins(1,4,5)P3 requires the participation of a small region of the ER, which is distinguished from other regions of the ER by a different apparent affinity for Ins(1,4,5)P3 analogues and is associated with the plasma membrane through the actin skeleton. This conclusion is discussed briefly in relation to current hypotheses for the activation of SOCs.
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PMID:Evidence for the involvement of a small subregion of the endoplasmic reticulum in the inositol trisphosphate receptor-induced activation of Ca2+ inflow in rat hepatocytes. 1039 99

In a previous study we overexpressed the thapsigargin (tg)-insensitive Pmr1 Ca(2+) pump of the Golgi apparatus of Caenorhabditis elegans in COS-1 cells and studied the properties of the Ca(2+) store into which it was integrated. Here we assessed the properties of an endogenous tg-insensitive nonmitochondrial Ca(2+) store in A7r5 and 16HBE14o- cells, which express a mammalian homologue of Pmr1. The tg-insensitive Ca(2+) store was considerably less leaky for Ca(2+) than the sarco(endo)plasmic-reticulum Ca(2+)-ATPase (SERCA)-containing Ca(2+) store. Moreover like for the worm Pmr1 Ca(2+) pump expressed in COS-1 cells, Ca(2+) accumulation into the endogenous tg-insensitive store showed a 2 orders of magnitude lower sensitivity to cyclopiazonic acid than the SERCA-mediated transport. 2,5-Di-(tert-butyl)-1,4-benzohydroquinone was only a very weak inhibitor of the tg-insensitive Ca(2+) uptake in A7r5 and 16HBE14o- cells and in COS-1 cells overexpressing the worm Pmr1. Inositol 1,4,5-trisphosphate released 11% of the Ca(2+) accumulated in permeabilized A7r5 cells pretreated with tg with an EC(50) that was 5 times higher than for the SERCA-containing Ca(2+) store but failed to release Ca(2+) in 16HBE14o- cells. In the presence of tg, 15% of intact A7r5 cells responded to 10 microm arginine-vasopressin with a small rise in cytosolic Ca(2+) concentration after a long latency. In conclusion, A7r5 and 16HBE14o- cells express a Pmr1-containing Ca(2+) store with properties that differ substantially from the SERCA-containing Ca(2+) store.
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PMID:Ca2+ uptake and release properties of a thapsigargin-insensitive nonmitochondrial Ca2+ store in A7r5 and 16HBE14o- cells. 1186 57


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