Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influx of calcium in response to vasopressin receptor stimulation is an important component of excitation-contraction coupling. We have examined the routes by which Ca2+ and other divalent cations enter vascular smooth muscle cells using a cultured vascular smooth muscle cell line (A7r5). Confluent A7r5 cells were loaded with Fura-2 to permit measurement of intracellular divalent cation concentration (Ca2+, Ba2+, Mn2+). Combinations of excitation wavelengths (340/380, 340/356, 356/380 and 340/370) were used depending on the divalent cation being studied. Emission was measured at 510 nm for all studies. Ca2+, Ba2+ and Mn2+ permeated unstimulated A7r5 cells. Vasopressin increased intracellular Ca2+ in cells both in the presence and absence of extracellular Ca2+, although responses in the absence of extracellular Ca2+ were smaller and had no sustained component. Amlodipine, a voltage-dependent calcium channel blocker, had no effect on Ca2+ entry, but Ni2+ did block Ca2+ influx. Vasopressin-induced elevations of intracellular Ca2+ in Ca(2+)-free physiological saline were abolished by ionomycin and thapsigargin. In the presence of extracellular Ba2+ vasopressin increased intracellular Ca2+ transiently and caused a small sustained increase in intracellular Ba2+ concentration. Ionomycin and thapsigargin increased intracellular Ca2+ but had no effect on Ba2+ influx. In contrast vasopressin, ionomycin and thapsigargin had no effect on Mn2+ influx. Econazole and SKF 96365, imidazoles reported to be blockers of receptor-induced cation entry, increased intracellular Ca2+ by releasing intracellular Ca2+ from a different site to that mobilized by vasopressin or thapsigargin in A7r5 cells. Econazole and SKF 96365 partially inhibited passive influx of Ca2+ and Ba2+ but did not inhibit passive influx of Mn2+, or vasopressin-induced influx of Ba2+. U73122, a putative inhibitor of phospholipase C partially inhibited passive entry of Ca2+ but not passive entry of Mn2+ and Ba2+. U73122 also inhibited vasopressin-induced release of intracellular Ca2+ and agonist-induced Ca2+ influx but did not block vasopressin-induced Ba2+ influx. Divalent cations enter A7r5 cells by a number of routes - 'passive' pathway(s) that admit Ca2+, Ba2+ and Mn2+ and receptor-operated pathway(s) that are permeable to Ca2+, Ba2+ but not Mn2+. On the basis of ionic permeabilities and the effect of various blocking agents, there appear to be two distinct passive influx routes. One is permeable to Ca2+ and Ba2+ and is blocked by econazole or SKF 96365. The other is permeable to Mn2+ and is blocked by Ni2+. There also appear to be two different routes of divalent cation entry involved in responses to receptor activation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Multiple pathways for entry of calcium and other divalent cations in a vascular smooth muscle cell line (A7r5). 805 48

The effect of econazole on intracellular calcium levels ([Ca2+]i) in Madin Darby canine kidney cells was investigated using fura-2 fluorimetry. Econazole increased [Ca2+]i dose-dependently at 5-50 microM. The Ca2+ signal consisted of an initial rise, a gradual decay and a sustained plateau. Extracellular Ca2+ removal partially reduced the econazole response. Mn2+ quench of fura-2 fluorescence confirmed econazole-induced Ca2+ influx. The econazole-sensitive intracellular Ca2+ store overlaps with that sensitive to thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+ pump, because 25 microM econazole depleted the thapsigargin-sensitive store, and conversely, thapsigargin abolished the econazole response. Econazole (25-50 microM) partially inhibited capacitative Ca2+ entry induced by cyclopiazonic acid, another endoplasmic reticulum Ca2+ pump inhibitor, measured by depleting internal Ca2+ store in Ca(2+)-free medium followed by adding 10 mM CaCl2. Econazole induced capacitative Ca2+ entry itself. Pretreatment with La3+ (100 microM) partially inhibited 25 microM econazole-induced Mn2+ quench of fura-2 fluorescence, and La3+ immediately reduced 20 microM econazole-induced Ca2+ signal when added at the peak of the signal, suggesting that econazole induced Ca2+ influx via two separate pathways: one is sensitive to La3+, the other is not. La3+ enlarged 25 microM econazole-induced [Ca2+]i transient during the decay phase. The econazole response was not altered when the cytosolic level of inositol 1,4,5-trisphosphate was inhibited by the phospholipase C inhibitor U73122.
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PMID:Multiple effects of econazole on calcium signaling: depletion of thapsigargin-sensitive calcium store, activation of extracellular calcium influx, and inhibition of capacitative calcium entry. 999 Mar 6

1. Econazole is used clinically as an antifungal drug with many different in vitro effects. However, the effects of econazole on prostate cancer cells are unknown. The effects of econazole on intracellular Ca2+ concentrations ([Ca2+]i) in and the proliferation of human PC3 prostate cancer cells was explored in the present study using fura-2 and tetrazolium as fluorescent dyes. 2. At a concentration of 0.1 micromol/L, econazole started to increase [Ca2+]i in a concentration-dependent manner. The econazole-induced increase in [Ca2+]i was reduced by 48% by removal of extracellular Ca2+, suggesting that the econazole-induced increase in [Ca2+]i was composed of extracellular Ca2+ influx and intracellular Ca2+. 3. This econazole-induced Ca2+ influx was via an L-type Ca2+ channel-like pathway. In Ca2+-free medium, 1 micromol/L thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+-ATPase, caused a monophasic increase in [Ca2+]i, after which the effect of econazole to increase [Ca2+]i was substantially inhibited. Conversely, pretreatment with 5 micromol/L econazole to deplete intracellular Ca2+ stores totally prevented thapsigargin from releasing more Ca2+. 4. The phospholipase C (PLC) inhibitor U73122 (2 micromol/L) abolished the increase in [Ca2+]i induced by 10 micromol/L ATP (a Ca2+ mobilizer that needs inositol 1,4,5-trisphosphate). 5. Overnight incubation with 1-30 micromol/L econazole inhibited proliferation of PC3 cells in a concentration-dependent manner. 6. These findings suggest that, in PC3 cells, econazole increases [Ca2+]i by stimulating Ca2+ influx into cells and Ca2+ release from the endoplasmic reticulum via a PLC-independent mechanism. Econazole is cytotoxic at submicromolar concentrations.
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PMID:Effects of econazole on Ca2+ levels in and the growth of human prostate cancer PC3 cells. 1617 30

Econazole is an antifungal drug with different in vitro effects. However, econazole's effect on osteoblast-like cells is unknown. In human MG63 osteosarcoma cells, the effect of econazole on intracellular Ca2+ concentrations ([Ca2+]i) was explored by using fura-2. At a concentration of 0.1 microM, econazole started to cause a rise in [Ca2+]i in a concentration-dependent manner. Econazole-induced [Ca2+]i rise was reduced by 74% by removal of extracellular Ca2+. The econazole-induced Ca2+ influx was mediated via a nimodipine-sensitive pathway. In Ca2+ -free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca+ -ATPase, caused a [Ca2+]i rise, after which the increasing effect of econazole on [Ca2+]i was abolished. Pretreatment of cells with econazole to deplete Ca2+ stores totally prevented thapsigargin from releasing Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5-trisphosphate-dependent Ca2+ mobilizer)-induced, but not econazole-induced, [Ca2+]i rise. Econazole inhibited 76% of thapsigargin-induced store-operated Ca2+ entry. These findings suggest that in MG63 osteosarcoma cells, econazole increases [Ca2+]i by stimulating Ca2+ influx and Ca2+ release from the endoplasmic reticulum via a phospholipase C-independent manner. In contrast, econazole acts as a potent blocker of store-operated Ca2+ entry.
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PMID:Econazole induces increases in free intracellular Ca2+ concentrations in human osteosarcoma cells. 1623 34

The effects of econazole, an antifungal drug applied for treatment of keratitis and mycotic corneal ulcer, on cytosolic-free Ca(2+) concentrations ([Ca(2+)](i)) and viability of corneal cells was examined by using SIRC rabbit corneal epithelial cells as model. [Ca(2+)](i) and cell viability were measured by using the fluorescent dyes fura-2 and WST-1, respectively. Econazole at concentrations > or = 1 microM increased [Ca(2+)](i) in a concentration-dependent manner. The Ca(2+) signal was reduced partly by removing extracellular Ca(2+). The econazole-induced Ca(2+) influx was insensitive to L-type Ca(2+) channel blockers and protein kinase C modulators. In Ca(2+)-free medium, after pretreatment with 20 microM econazole, [Ca(2+)](i) rises induced by 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) were abolished. Conversely, thapsigargin pretreatment also abolished econazole-induced [Ca(2+)](i) rises. Inhibition of phospholipase C with 2 microM U73122 did not change econazole-induced [Ca(2+)](i) rises. At concentrations between 10 and 80 microM, econazole killed cells in a concentration-dependent manner. The cytotoxic effect of 20 microM econazole was not reversed by prechelating cytosolic Ca(2+) with BAPTA. This shows that in SIRC cells econazole induces [Ca(2+)](i) rises by causing Ca(2+) release from the endoplasmic reticulum and Ca(2+) influx from unknown pathways. Econazole-caused cytotoxicity was independent from a preceding [Ca(2+)](i) rise.
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PMID:Econazole-evoked [Ca2+]i rise and non-Ca2+-triggered cell death in rabbit corneal epithelial cells (SIRC). 1906 Oct 74