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)

Platelets are discoid, anucleate cells with a large number of secretory granules. Physiological agonists (thrombin, collagen, ADP, adrenaline, thromboxane A2, serotonin, vasopressin) interact with specific receptors on the platelet surface which causes the platelet responses shape change, aggregation, secretion of substances from three types of granules and liberation of arachidonate from membrane phospholipids. Some secreted substances and conversion products of arachidonate are platelet agonists and enhance platelet stimulation (positive feedback). The shape change and aggregation responses are of central importance for platelet adhesion to the subendothelium and formation of platelet thrombi. Dense granule secretion and the storage of ADP, ATP, Ca2+ and serotonin, a-granule secretion of platelet-specific, cationic, coagulation and carbohydrate-containing proteins as well as secretion of glycosidases are also shown to be important for platelet participation in haemostasis and thrombosis. Signal transduction mechanisms (phospholipase C activation, polyphosphoinositide metabolism, Ca2+ mobilization) and arachidonate oxygenation are central processes for the physiological functions of platelets.
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PMID:Physiological functions of platelets. 253 34

Arginine vasopressin (AVP) has been shown previously to enhance phosphatidylinositol (PI) turnover and mobilize calcium in the rat aortic smooth muscle cell-line (A10; ATCC CRL 1476) via the V1 receptor (Aiyar, N., Nambi, P., Stassen, F. L., and Crooke, S. T. (1986) Life Sci. 39, 37-45). Exposure of A10 cells to AVP for periods ranging from 5 min to 2 h resulted in 30-40% loss in AVP-binding sites and an inhibition of the production of inositol di- and trisphosphates and the mobilization of calcium when the cells were rechallenged by addition of AVP. We now report that during the same time course AVP induces a dose- and time-dependent decrease in labeled PI, phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate reaching a minimum after 30 min of incubation. After 2 h of exposure to AVP, the levels of labeled PI, phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate increased to a new basal level approximately 30% less than the untreated cultures. The decrease in inositol lipid labeling mediated by AVP was inhibited when the V1 antagonist SK&F 100273 was included in the incubations with AVP. No decrease was observed when the V2 agonist 1-deamino, [8-D-arginine]vasopressin was used for pretreatment of the cells. Furthermore, when PI kinase activity was measured in cell extracts from untreated and AVP-treated (2 h) cells a significant decrease (p less than 0.05) was observed in the absence, but not in the presence, of added PI in the AVP-treated cells as compared with the control cells. Thrombin also stimulates PI metabolism and calcium mobilization in these cells and brought about both a prolonged decrease in inositol lipids and inhibition of PI kinase activity. AVP pretreatment affected the release of intracellular Ca2+ induced by AVP, thrombin, and ATP, differently. The time of AVP pretreatment required to induce half-maximal inhibition of intracellular Ca2+ release in response to AVP, thrombin, and ATP was approximately 8, 24, and 30 min, respectively. Consequently, we suggest that the reduction in response to AVP with short term preincubation is due to homologous desensitization as reflected by 30-40% decrease in V1 receptors. Subsequently, a decrease in inositol lipid pools and PI kinase activity results in heterologous desensitization in response to AVP, thrombin, and ATP.
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PMID:Molecular mechanisms of homologous and heterologous desensitization mediated by vasopressin in smooth muscle cells. 253 19

The regulation of cytosolic calcium in LLC-PK1 cells by various agonists was characterized. Arginine vasopressin (AVP, 100 nM) rapidly increased cytosolic calcium (Caf) measured with fura-2 from a basal level of 65 +/- 5 to 516 +/- 102 nM followed by a return to a plateau level of 128 +/- 18 nM. Similar responses to 100 nM lysine vasopressin were seen. AVP also increased adenosine 3',5'-cyclic monophosphate (cAMP) as previously documented for these cells. A V2-selective AVP analogue increased cAMP without affecting Caf, whereas two V1-receptor antagonists prevented the Caf response to AVP without altering the cAMP response. Increasing cellular cAMP with forskolin, cholera toxin, or stable cAMP analogues did not affect Caf or the response of Caf to AVP. Both adenosine and ATP produced large Caf transients at concentrations of 1-10 microM in both calcium-containing media and after acute chelation of medium Ca with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). The A1-selective adenosine analogue, (R-phenyl-isopropyl)-adenosine, and the A2-selective analogue, 5'-(N-ethyl)-carboxamido-adenosine, both produced Caf responses similar to adenosine. The Caf responses to adenosine and its analogues but not to ATP were blocked by the adenosine receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine. Islet-activating protein, pertussis toxin, inhibited the Caf response to adenosine and enhanced the cAMP response to AVP. Responses to all agonists were demonstrable in greater than 80% of single cells studied by microfluorometry, and individual cells responded to multiple agonists. These studies indicate that the Caf and cAMP responses to AVP in the LLC-PK1 cell line involve separate receptors, and they document the presence in this cell line of at least two types of receptors for exogenous purines.
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PMID:Alterations of cytosolic calcium in LLC-PK1 cells induced by vasopressin and exogenous purines. 254 21

Treatment of intact adipocytes with either or both insulin and adrenaline stimulated membrane cyclic AMP phosphodiesterase activity only in the endoplasmic reticulum subfraction. The cyclic GMP-inhibited cyclic AMP phosphodiesterase activity was also found in this fraction. Quantitative Western blotting using a specific polyclonal antibody, raised against the homogeneous 'dense-vesicle' cyclic AMP phosphodiesterase from rat liver, identified a single 63 kDa species which was localized in the adipocyte endoplasmic reticulum fraction. The ability of adrenaline to stimulate adipocyte membrane cyclic AMP phosphodiesterase was shown to be mediated via beta-adrenoceptors and not alpha 1-adrenoceptors. Membrane cyclic AMP phosphodiesterase was stimulated by glucagon but not by vasopressin, A23187 or 12-O-tetradecanoylphorbol 13-acetate (TPA). Treatment of adipocytes with either chloroquine or dansyl cadaverine failed to affect the ability of insulin to stimulate cyclic AMP phosphodiesterase activity. Treatment of an isolated adipocyte endoplasmic reticulum membrane fraction with purified protein kinase A increased its cyclic AMP phosphodiesterase activity some 2-fold. When this fraction was treated with purified protein kinase A and [32P]ATP, label was incorporated into a 63 kDa protein which was specifically immunoprecipitated with the antiserum against the liver 'dense-vesicle' cyclic AMP phosphodiesterase.
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PMID:Subcellular localization and hormone sensitivity of adipocyte cyclic AMP phosphodiesterase. 255 12

Treatment of hepatocytes with 2,5-di-(tert-butyl)-1,4-benzohydroquinone (tBuBHQ), a novel mobilizer of the inositol 1,4,5-trisphosphate-sensitive Ca2+ pool, produces a sustained elevation of [Ca2+]i (Kass, G. E. N., Duddy, S. K., and Orrenius, S. (1989) J. Biol. Chem. 264, 15192-15198). Exposure of hepatocytes to the Ca2(+)-mobilizing hormones, vasopressin, angiotensin II, or ATP following [Ca2+]i elevation by tBuBHQ produced a rapid return of [Ca2+]i to basal or near basal levels. Release of the inositol 1,4,5-trisphosphate-sensitive Ca2+ pool by tBuBHQ following pretreatment with vasopressin or angiotensin II resulted in a [Ca2+]i transient and not the sustained [Ca2+]i elevation observed in the absence of the Ca2(+)-mobilizing hormones. The G-protein activator, NaF plus AlCl3, mimicked both effects of the Ca2(+)-mobilizing hormones on [Ca2+]i. The mechanism for Ca2+ removal from the cytosol by Ca2(+)-mobilizing hormones did not involve cyclic nucleotides nor did it require protein kinase C activation or cyclo- and lipoxygenase-dependent metabolites of arachidonic acid. Furthermore, the hormone-mediated decrease in [Ca2+]i did not involve the pertussis toxin-sensitive Gi-protein. Removal of the tBuBHQ-mobilized Ca2+ from the cytosol of hepatocytes by Ca2(+)-mobilizing hormones was mediated by stimulation of a Ca2+ efflux pathway. Thus, in addition to initiating [Ca2+]i transients by releasing Ca2+ from the inositol 1,4,5-trisphosphate-sensitive Ca2+ store and stimulating Ca2+ influx, Ca2(+)-mobilizing hormones also regulate the termination of the [Ca2+]i transient by stimulating a Ca2+ efflux pathway.
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PMID:Ca2(+)-mobilizing hormones stimulate Ca2+ efflux from hepatocytes. 255 86

1. The effects of the alpha2-adrenoceptor agonists clonidine, rilmenidine, TL99 and UK14304 on the vasoconstrictor response to sympathetic nerve stimulation and on the concentration-response curves to noradrenaline and phenylephrine were compared in two isolated, perfused vascular tissues: the rat tail artery (which has both postjunctional alpha 1- and alpha 2-adrenoceptors), and the rabbit ear artery (in which only alpha 1-adrenoceptors are present postjunctionally). 2. In the rabbit ear artery, the first observable effect of alpha 2-adrenoceptor agonists was inhibition of vasoconstrictor responses to sympathetic nerve stimulation. This occurred with concentrations of the alpha 2-adrenoceptor agonists which were far below those producing vasoconstriction. Responses to noradrenaline were not affected. 3. In contrast, in the rat isolated perfused tail artery, alpha 2-adrenoceptor agonists, in concentrations that produced no other observable effects, enhanced the vasoconstrictor responses to sympathetic nerve stimulation and to noradrenaline. Much higher concentrations of alpha 2-adrenoceptor agonists produced vasoconstriction in most preparations and only then reduced the response to sympathetic nerve stimulation. The enhancing effect of alpha 2-adrenoceptor agonists was blocked by idazoxan, but not by prazosin. 4. Vasoconstrictor responses in the rat tail artery to the relatively selective alpha 1-adrenoceptor agonist phenylephrine were enhanced by alpha 2-adrenoceptor agonists. The enhancement of the response to phenylephrine was greater than that to the mixed alpha 1- and alpha 2-adrenoceptor agonist noradrenaline. 5. Vasoconstrictor responses in the rat tail artery to vasopressin, ATP and KCl, like those to alpha 1-adrenoceptor agonists, were enhanced by alpha 2-adrenoceptor agonists.2+owever, vasoconstrictor responses to
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PMID:Alpha 2-adrenoceptor agonists enhance responses to certain other vasoconstrictor agonists in the rat tail artery. 256 48

Changes in metabolic state of rabbit livers after administration of vasopressin (10 mU/kg/min d.i.v.) were evaluated using in vivo P-31 magnetic resonance (MR) spectroscopy. Targets were nine normal control rabbits and eight with chronically carbon tetrachloride-damaged livers. A 2.0 Tesla whole-body MR imager was used for measurement. After administration of vasopressin, liver spectroscopy showed a mild ischemic pattern. The inorganic phosphate peak increased statistically significantly (p less than 0.05) both in the normal control group and in the damaged-liver group (20% and 16% above base line value respectively). In the normal control group, there was a statistically significant decrease (p less than 0.05) in the ATP peak to 18% below the base line value while the PME (phosphomonoester) peak increased slightly (about 10%); there was little change in the damaged-liver group. It was thought that the difference between the two groups was due to differences in blood flow mechanism and liver metabolism. Magnetic resonance spectroscopy was considered to be useful in studying the detailed changes in metabolic state of rabbit liver after administration of vasopressin.
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PMID:[Effect of vasopressin on rabbit hepatic energy metabolism evaluated using in vivo P-31 magnetic resonance spectroscopy]. 258 96

The binding of [3H]Ins(1,4,5)P3 to bovine adrenocortical microsomes has been shown to be rapid, reversible and saturable. The microsomal preparation contained a single population of high affinity sites (KD = 6.82+/-2.3 nM, Bmax = 370+/-38 fmol/mg protein). The binding site was shown to exhibit positional specificity with respect to inositol trisphosphate binding, i.e. Ins(2,4,5)P3 was able to compete with [3H]Ins(1,4,5)P3 whereas Ins(1,3,4)P3 was not. Ins(1,3,4,5)P4 showed a similar affinity for the receptor as Ins(2,4,5)P3 whereas the other inositol phosphates tested, ATP, GTP and 2,3-DPG, were poor competitors. [3H]Ins(1,4,5)P3-binding was independent of free Ca2+ concentrations. The adrenocortical microsomal preparation has been incorporated into an assay which has been used to determine the basal and vasopressin-stimulated content of neutralised acid extracts of rat hepatocytes. Intracellular concentrations of Ins(1,4,5)P3 were calculated to be 0.22+/-0.15 microM basal and 2.53+/-1.8 microM at peak stimulation. This assay provides a simple, specific and quantitative method for the measurement of Ins(1,4,5)P3 concentrations in the picomolar range.
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PMID:Development of a novel, Ins(1,4,5)P3-specific binding assay. Its use to determine the intracellular concentration of Ins(1,4,5)P3 in unstimulated and vasopressin-stimulated rat hepatocytes. 264 27

The purpose of this article is to describe briefly the methods by which the intra-mitochondrial volume may be measured both in vitro and in situ, to summarise the mechanisms thought to regulate the mitochondrial volume and then to review in more detail the evidence that changes in the intra-mitochondrial volume play an important part in the regulation of liver mitochondrial metabolism by glucogenic hormones such as glucagon, adrenaline and vasopressin. It will be shown that these hormones cause an increase in matrix volume sufficient to produce significant activation of fatty acid oxidation, respiration and ATP production, pyruvate carboxylation, citrulline synthesis and glutamine hydrolysis. These are all processes activated by such hormones in vivo. I will go on to demonstrate that the increase in matrix volume is brought about by an increase in mitochondrial [PPi]. This is able to stimulate K+ entry into the matrix, perhaps through an interaction with the adenine nucleotide translocase. The rise in matrix [PPi] is a consequence of an increase in cytosolic and hence mitochondrial [Ca2+] which inhibits mitochondrial pyrophosphatase. In the final section of the review I provide evidence that changes in mitochondrial volume may be important in the responses of a variety of tissues to hormones and other stimuli. I write as a metabolist with a working knowledge of bioenergetics rather than the converse, and this will certainly be reflected in the approach taken. If I cause offence to any dedicated experts in the field of bioenergetic by my ignorance or lack of understanding of their studies I can only offer my apologies and ask to be corrected.
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PMID:The regulation of the matrix volume of mammalian mitochondria in vivo and in vitro and its role in the control of mitochondrial metabolism. 264 40

The effects of arginine-vasopressin (AVP) (0.01-1 microM) on membrane potential, [Ca2+]i and ATP-sensitive potassium channels have been studied in the insulin-secreting cell line RINm5F. In whole cells, with an average spontaneous cellular transmembrane potential of -64 +/- 3 mV (n = 33) and an average basal [Ca2+]i of 102 +/- 6 nM (n = 40), AVP evoked: (i) membrane depolarization, (ii) voltage-dependent Ca2+ spike-potentials and (iii) a sharp rise in [Ca2+]i. Single-channel current events recorded from excised outside-out membrane patches show that AVP closes potassium channels that are also closed by tolbutamide (100 microM) and opened by diazoxide (100 microM). AVP acts on KATP channels specifically from the outside of the membrane and a soluble cytosolic messenger appears not to be involved, since there is no channel activation in cell-attached membrane patches when the peptide is added to the bath solution.
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PMID:Vasopressin directly closes ATP-sensitive potassium channels evoking membrane depolarization and an increase in the free intracellular Ca2+ concentration in insulin-secreting cells. 268 44


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