Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UNIPROT:P01185 (vasopressin)
23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Agonists which stimulate the inositol 1,4,5 trisphosphate ([1,4,5]-IP3)-dependent mobilization of Ca2+ from intracellular stores also stimulate entry of divalent cations across the cell membrane. Under appropriate experimental conditions, divalent cation entry across the cell membrane can be monitored as the rate at which the intracellular fluorescence of divalent cation indicators is quenched by the addition of Mn2+ to the extracellular medium. We report that addition of vasopressin to fura-2-loaded glomerular mesangial cells in culture markedly accelerated the rate at which Mn2+ quenched fura-2 fluorescence at its Ca(2+)-insensitive wavelength in the presence of extracellular NaCl, but that this quench response was attenuated when Cl- was removed from the extracellular medium by equimolar substitution with impermeant anions (gluconate, methanesulfonate, acetate, lactate). Similarly, loss of agonist-induced quench also occurred when Cl- was substituted with gluconate in K(+)-containing media. Addition of the Cl- channel inhibitor, 5-nitro-2-(3-phenylpropylaminobenzoic acid) (NPPB), also inhibited Mn(2+)-induced quench of fura-2 fluorescence following vasopressin addition. In contrast, in the presence of gramicidin to provide an alternate conductance pathway to accompany divalent cation entry, agonist-dependent Mn2+ quench occurred even in the absence of extracellular Cl-, indicating that the requirement for Cl- was not the result of cotransport on a common transporter nor the result of Cl- serving as a necessary cofactor for divalent cation entry. A similar dependence on extracellular Cl- was observed for other Ca(2+)-mobilizing agonists such as endothelin, as well as the intracellular Ca2+ ATPase inhibitor, thapsigargin. Extracellular Cl- dependence for agonist-induced divalent cation entry was also reflected in a corresponding extracellular Cl- dependence for agonist-induced mesangial cell contraction. It has been previously shown by ourselves (Kremer et al., 1992a, Am. J. Physiol., 262:F668-F678) and others that agonist-stimulated calcium mobilization in mesangial cells is accompanied by inhibition of K+ conductance and increased Cl- conductance. Accordingly, we conclude that the current findings suggest that activation of Cl- conductance provides regulated charge compensation for receptor-mediated divalent cation entry in response to Ca(2+)-mobilizing vasoconstrictor agonists in mesangial cells.
...
PMID:Chloride is required for receptor-mediated divalent cation entry in mesangial cells. 752 36

An inward current responsible for hormone regulated Ca2+ entry has been identified in cultured rat hepatocytes using whole cell patch clamp. Addition of 20 nM vasopressin or of 100 microM ATP induced the inward current, which could be observed more clearly after blocking an outward K+ current. This large outward K+ current, which appeared after addition of vasopressin or ATP, could be blocked either by replacing K+ with Cs+ in the external medium and in the pipette solution, or by simply including 0.5 microM apamin in the K(+)-containing external medium. The outward current appears to be carried by a Ca2+ activated K+ channel. In the presence of apamin, hepatocytes pretreated with vasopressin in a Ca(2+)-free media reveal an inward current on addition of external Ca2+ (5 mM). The current could also be elicited by addition of vasopressin when cells are preincubated in the presence of 5 mM external Ca2+. No current is seen on addition of Ca2+ in the absence of vasopressin. Initially, the inward current was ca 200-300 pA at -60 mV, but it declined rapidly over 3 min to ca 20 pA. The current approached zero, as an asymptote at positive potential, and appeared to be somewhat inwardly rectifying. Additions of 5 mM Mn2+ or 5 mM Ba2+ in place of Ca2+ produced little or no current. An inhibitor of ER Ca(2+)-ATPase, thapsigargin, could also trigger the cascade of events leading to plasma membrane conductance of Ca2+. The data suggest that hormone-stimulated Ca2+ entry into hepatocytes is mediated by a Ca(2+)-release activated channel highly specific for Ca2+. This is the first demonstration of such a channel in hepatocytes, though similar ones have been described in mast cells, in vascular endothelial cells and T-lymphocytes.
...
PMID:Hormone-regulated Ca2+ channel in rat hepatocytes revealed by whole cell patch clamp. 758 80

Hypoxia effect on the nuclear of the Scorpaena porcus (L.) in vivo was studied. It was shown, that existence of the fishes in environmental with low oxygen concentration-1.3-1.4 mg.1-1 (15% initial saturation) resulted in reducing in activities of Na+, K(+)-ATPase, hexokinase and glucose-6-phosphate dehydrogenase in the erythrocyte for 50.0 (p < 0.001), 26.5% (p < 0.01) and 53.7% (p < 0.05) accordingly. ATP concentration in cells and membrane gradient of Na+, K+ concentrations between blood serum and intracellular environment did not change. A conclusion was made about a decrease of cells membrane penetration and oppression of intracellular metabolism. These changes proceeded on a background of the blood serum dehydration and decrease of the mean volume of erythrocytes. The part of aldosteron and vasopressin in membrane penetration of nuclear erythrocytes is discussed.
...
PMID:[Effect of hypoxia on biochemical parameters of Scorpaena erythrocytes]. 774 38

In this work we analyze the renal and systemic factors involved in the sodium retention in two conditions: in extracellular volume depletion and in edema forming states, particularly liver cirrhosis with ascitis. In this paper we accept that the volume loss of body fluids stimulates the "effective arterial blood volume" (VAE). This term results from a decrease in the arterial blood volume secondary to a fall in cardiac output or a peripheral arterial vasodilatation. The reduction in the VAE stimulates: the high pressure baroreceptors (carotid sinus and aortic arch); the intrarrenal mechanisms, such as the yuxtaglomerular apparatus and the renin angiotensin aldosterone system; the sympathetic adrenergic system; the non osmotic release of antidiuretic hormone; prostaglandins (PGE1, Tromboxane) and endothelin; and inhibits the atrial natriuretic peptide. We also describe the sodium transport mechanisms along the nephron during physiological conditions and after volume depletion, and in edema formation states, specially hepatic cirrhosis with ascitis. We speculate that the intrarenal mechanisms are more important and persistent than the systemic mechanisms. It is possible that the sodium retention of these states might be the result of direct stimuli of the tubular sodium transport mechanisms in the different segments of the nephron, mediated by the co and counter transports, ATPase activity or by the second messengers cyclic AMP and cyclic GMP. The clonation and structural characterization of the different sodium transports may help us to establish, more precisely, the intracellular tubular mechanisms responsible for the tendency of the body to retain sodium. The amount of information generated in the future may help us to demonstrate, with more precision, the mechanisms responsible for the sodium retention and excretion in normal and pathological conditions, particularly the edema forming states such as cardiac failure, nephrotic syndrome and hepatic cirrhosis with ascitis.
...
PMID:[Renal and extra-renal mechanisms of sodium and water retention in cirrhosis with ascites]. 777 18

We reported that feeding rats 8% protein for 3 wk induces net urea transport and morphologic changes in initial inner medullary collecting ducts (IMCDs) which are not present in rats fed 18% protein. In this study, we measured net urea transport in microperfused initial IMCDs from rats fed 8% protein for > or = 3 wk and tested the effect of inhibiting Na+/K(+)-ATPase activity and found that adding 1 mM ouabain to the bath reversibly inhibited net urea transport from 14 +/- 3 to 6 +/- 2 pmol/mm per min (P < 0.01), and that replacing potassium (with sodium) in the bath reversibly inhibited net urea transport from 18 +/- 3 to 5 +/- 0 pmol/mm per min (P < 0.01). Replacing perfusate sodium with N-methyl-D-glucamine reversibly inhibited net urea transport from 12 +/- 2 to 0 +/- 1 pmol/mm per min (P < 0.01), whereas replacing bath sodium had no significant effect on net urea transport. Adding 10 nM vasopressin to the bath exerted no significant effect on net urea transport. Finally, we measured Na+/K(+)-ATPase activity in initial and terminal IMCDs from rats fed 18% or 8% protein and found no significant difference in either subsegment. Thus, net urea transport in initial IMCDs from rats fed 8% protein for > or = 3 wk requires sodium in the lumen, is reduced by inhibiting Na+/K(+)-ATPase, and is unchanged by vasopressin or phloretin. These results suggest that net urea transport may occur via a novel, secondary active, sodium-urea cotransporter.
...
PMID:Sodium-dependent net urea transport in rat initial inner medullary collecting ducts. 792 27

We examined the effect of the depletion of intracellular Ca2+ stores on Ca2+ influx in rat glomerulosa cells. Depletion of intracellular Ca2+ stores was achieved by inhibiting sarco/endoplasmic reticulumtype Ca(2+)-ATPase with thapsigargin or 2,5,di-(t-butyl)-1,4-benzohydroquinone (t-BHQ). Both inhibitors induced a sustained rise in cytoplasmic Ca2+ concentration. The initial rise was observed also in Ca(2+)-free medium, while the sustained phase disappeared, indicating that the latter requires Ca2+ influx. In Ca(2+)-free medium, the readdition of Ca2+ induced a steeper and higher rise in intracellular Ca2+ concentration in thapsigargin-treated cells than in controls, supporting the role of Ca2+ influx. In normal medium, the addition of Cd2+ (80 microM) evoked an immediate inhibition of the sustained phase of thapsigargin response. The response to thapsigargin was insensitive to nifedipine. Thapsigargin failed to enhance Mn2+ quenching of fura 2. Our results provide evidence for the existence of capacitative Ca2+ influx in rat glomerulosa cells and indicate that dihydropyridine-sensitive Ca2+ channels do not participate in capacitative Ca2+ entry. High concentrations of thapsigargin and t-BHQ, similar to the reported effects of angiotensin II and vasopressin, inhibited K(+)-induced Ca2+ signals. These effects appear, however, to be independent of the depletion of internal Ca2+ stores.
...
PMID:Capacitative Ca2+ influx in adrenal glomerulosa cells: possible role in angiotensin II response. 797 88

We found that thapsigargin (Tg), a non-phorbol ester type tumor promoter that specifically inhibits endoplasmic reticulum Ca(2+)-ATPase, transiently increased the level of cytosolic free calcium ([Ca2+]i) and subsequently induced chromatin condensation, nuclear fragmentation, and internucleosomal DNA cleavage in cultured PLC/PRF/5 human hepatoma cells. These alterations were followed by the loss of plasma membrane integrity and by cell death. Epidermal growth factor (EGF) and vasopressin similarly elevated [Ca2+]i without causing DNA fragmentation which is characteristic of apoptosis. Consequently, the elevation of [Ca2+]i itself was not sufficient for causing Tg-induced cell death. On the other hand, preculturing the cells with Tg completely suppressed Ca2+ mobilization induced by EGF and vasopressin; a result that strongly suggests that Tg depleted the endoplasmic reticulum Ca2+ pool. Such depletion is hypothesized to induce apoptotic cell death in this hepatoma cell line by changing the nuclear Ca2+ levels which probably produce a structural change in chromatin.
...
PMID:Thapsigargin-induced persistent intracellular calcium pool depletion and apoptosis in human hepatoma cells. 801 72

Vasopressin (VP) stimulates adenosine 3',5'-monophosphate (cAMP) formation in an immortalized renal tubule cell line, TKC2, which is derived from transgenic mouse harboring temperature-sensitive SV40 T-antigen gene. VP (10(-8) M)-induced cAMP formation was significantly attenuated by either non-peptide vasopressin receptor V1 or V2 subtype antagonist, OPC-21268 (10(-8) and 10(-6) M) or OPC-31260 (10(-8) and 10(-6) M), respectively, and it was completely abolished by combination of both agents (10(-6) M). VP (10(-8) M) also induced an increase in cytosolic free Ca2+ and prostaglandin (PG) E2 synthesis, both of which were significantly inhibited by OPC-21268 (10(-8) M), but not by OPC-31260 (10(-6) M). Either OPC-21268 (10(-8) M), depletion of extracellular Ca2+ or inhibition of cyclooxygenase attenuated both VP-induced PGE2 synthesis and cAMP formation. In conclusion, both V1 and V2 receptors can stimulate cAMP formation. V1 receptor, however, stimulates cAMP formation via Ca(2+)-dependent PGE2 synthesis, whereas V2 receptor may stimulate it directly.
...
PMID:Different cellular mechanisms of vasopressin receptor V1 and V2 subtype in vasopressin-induced adenosine 3', 5'-monophosphate formation in an immortalized renal tubule cell line, TKC2. 804 37

The plasma membrane composition of virtually all eukaryotic cells is maintained and continually modified by the recycling of specific protein and lipid components. In the kidney collecting duct, urinary acidification and urinary concentration are physiologically regulated at the cellular level by the shuttling of proton pumps and water channels between intracellular vesicles and the plasma membrane of highly specialized cell types. In the intercalated cell, hydrogen ion secretion into the urine is modulated by the recycling of vesicles carrying a proton pumping ATPase to and from the plasma membrane. In the principal cell, the antidiuretic hormone, vasopressin, induces the insertion of vesicles that contain proteinaceous water channels into the apical cell membrane, thus increasing the permeability to water of the epithelial layer. In both cell types, 'coated' carrier vesicles are involved in this process, but whereas clathrin-coated vesicles are involved in the endocytotic phase of water channel recycling, the transporting vesicles in intercalated cells are coated with the cytoplasmic domains of the proton pumping ATPase. By a combination of morphological and functional techniques using FITC-dextran as an endosomal marker, we have shown that recycling endosomes from intercalated cells are acidifying vesicles but that they do not contain water channels. In contrast, principal cell vesicles that recycle water channels do not acidify their lumens in response to ATP. These non-acidic vesicles lack functionally important subunits of the vacuolar proton ATPase, including the 16 kDa proteolipid that forms the transmembrane proton pore. Because these endosomes are directly derived via clathrin-mediated endocytosis, our results indicate that endocytotic clathrin-coated vesicles are non-acidic compartments in principal cells. In contrast, recycling vesicles in intercalated cells contain large numbers of proton pumps, arranged in hexagonally packed arrays on the vesicle membrane. These pumps are inserted into the apical plasma membrane of A-type (acid-secreting) intercalated cells, and the basolateral plasma membrane of B-type (bicarbonate-secreting) cells in the collecting duct. Both apical and basolateral targeting of H(+)-ATPase-containing vesicles in these cells may be directed by microtubules, because polarized insertion of the pump into both membrane domains is disrupted by microtubule depolymerizing agents. However, the basolateral localization of other transporting proteins in intercalated cells, including the band 3-like anion exchanger and facilitated glucose transporters, is not affected by microtubule disruption.
...
PMID:Endosomal pathways for water channel and proton pump recycling in kidney epithelial cells. 814 5

Collagenase dispersed rat liver hepatocytes release Mg2+ when stimulated with norepinephrine or accumulate Mg2+ when stimulated with vasopressin, respectively. Mg2+ fluxes in either direction account for a net loss or gain of approximately 10% of total cell magnesium and are rapidly reversible. Both stimulated Mg2+ efflux and Mg2+ influx require physiological concentration of extracellular NaCl and Ca2+. In the absence of extracellular Na+, Mg2+ efflux, but not influx, can be observed in the presence of extracellular Cl-. Under these conditions, the efflux is inhibited by the Cl-/HCO3- exchanger inhibitor 4,4'-dinitrostilbene-2,2'-disulfonic acid. In hepatocytes, Mg2+ influx, but not efflux, is completely inhibited by thapsigargin, a specific inhibitor of the endoplasmic reticulum Ca2+ ATPase. Several lines of evidence, such as measurements of cytosolic Ca2+ or of cytosolic Ca2+ buffering, indicate that the effect of thapsigargin in inhibiting Mg2+ influx could not be explained by an increase in cytosolic Ca2+. Instead, the inhibition of hepatocyte Mg2+ influx was found to be the result of the depletion of the Ca2+ stored within the endoplasmic reticulum.
...
PMID:Hormonal stimulation of Mg2+ uptake in hepatocytes. Regulation by plasma membrane and intracellular organelles. 834 Mar 77


<< Previous 1 2 3 4 5 6 7 8 9 10

---