Cyclopiazonic acid stimulates Ca2+ influx through non-specific cation channels in endothelial cells

1994 ◽  
Vol 251 (2-3) ◽  
pp. 119-125 ◽  
Author(s):  
He Zhang ◽  
Masato Inazu ◽  
Bryce Weir ◽  
Michael Buchanan ◽  
Ed Daniel
Keyword(s):  
Endothelial Cells ◽  
Cyclopiazonic Acid ◽  
Cation Channels

Role of endothelial Ni2+-sensitive Ca2+entry pathway in regulation of EDHF in porcine coronary artery

2001 ◽  
Vol 280 (2) ◽  
pp. H730-H737 ◽  
Author(s):  
Hiroshi Tomioka ◽  
Yuichi Hattori ◽  
Mitsuhiro Fukao ◽  
Hiroshi Watanabe ◽  
Yasuhiro Akaishi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Coronary Artery ◽  
Cyclopiazonic Acid ◽  
Temporal Correlation ◽  
Cation Channels ◽  
Induced Response ◽  
Membrane Hyperpolarization ◽  
Aortic Endothelial Cells ◽  
Porcine Coronary Artery ◽  
Nonselective Cation Channels

Elevation of intracellular Ca2+ concentration ([Ca2+]i) in endothelial cells is proposed to be required for generation of vascular actions of endothelium-derived hyperpolarizing factor (EDHF). This study was designed to determine the endothelial Ca2+ source that is important in development of EDHF-mediated vascular actions. In porcine coronary artery precontracted with U-46619, bradykinin (BK) and cyclopiazonic acid (CPA) caused endothelium-dependent relaxations in the presence of N G-nitro-l-arginine (l-NNA). The l-NNA-resistant relaxant responses were inhibited by high K+, indicating an involvement of EDHF. In the presence of Ni2+, which inhibits Ca2+ influx through nonselective cation channels, the BK-induced EDHF relaxant response was greatly diminished and the CPA-induced response was abolished. BK and CPA elicited membrane hyperpolarization of smooth muscle cells of porcine coronary artery. Ni2+ suppressed the hyperpolarizing responses in a manner analogous to removal of extracellular Ca2+. EDHF-mediated relaxations and hyperpolarizations evoked by BK and CPA in porcine coronary artery showed a temporal correlation with the increases in [Ca2+]i in porcine aortic endothelial cells. The extracellular Ca2+-dependent rises in [Ca2+]i in endothelial cells stimulated with BK and CPA were completely blocked by Ni2+. These results suggest that Ca2+ influx into endothelial cells through nonselective cation channels plays a crucial role in the regulation of EDHF.

CPA enhances Ca2+ entry in cultured bovine pulmonary arterial endothelial cells in an IP3-independent manner

1995 ◽  
Vol 268 (1) ◽  
pp. H138-H146 ◽  
Author(s):  
E. Pasyk ◽  
M. Inazu ◽  
E. E. Daniel
Keyword(s):  
Endothelial Cells ◽  
Cell Membrane ◽  
Outward Current ◽  
Cyclopiazonic Acid ◽  
Rat Aorta ◽  
Cation Channels ◽  
Independent Manner ◽  
Nonselective Cation Channels ◽  
Patch Pipette ◽  
K Current

Studies of rat aorta revealed that cyclopiazonic acid (CPA), an inhibitor of the endoplasmic reticulum Ca2+ pump, released endothelium-derived relaxing factor (EDRF) and relaxed the muscle. We have used CPA to elucidate how this inhibitor of Ca2+ uptake into internal stores affects K+ channels and Ca2+ entrance in cultured bovine pulmonary endothelial cells using patch-clamp techniques. CPA increased a Ca(2+)-dependent outward K+ current for many minutes, presumably as a consequence of the unbalanced leakage of Ca2+ from internal stores and Ca2+ entrance across the cell membrane. An expected consequence of this activation of the outward current change is hyperpolarization of the cell membrane and increased driving force for Ca2+ entry. CPA activated the influx of extracellular Ca2+ through nonselective cation channels. Ca2+ influx through nonselective cation channels could help maintain intracellular Ca2+ concentration elevation and EDRF release. CPA also reduced the inwardly rectifying K+ current. Inositol 1,4,5-trisphosphate (IP3) in the patch pipette also produced an increase in outward K+ currents, which were Ca2+ dependent. After depletion of Ca2+ internal stores by CPA, the response to IP3 was abolished. Heparin in the patch pipette reduced the increase in outward currents induced by bradykinin, an agonist known to raise IP3 and to release Ca2+, but did not prevent CPA-induced increases in outward current. Thus CPA acts to elevate Ca(2+)-activated currents in endothelial cells by a mechanism independent of IP3-induced release, and this may lead to EDRF release both directly and as a consequence of Ca2+ entry through nonselective cation channels driven by an increased electrical gradient for Ca2+.

scholarly journals Mitochondrial connexin40 regulates mitochondrial calcium uptake in coronary endothelial cells

2017 ◽  
Vol 312 (4) ◽  
pp. C398-C406 ◽  
Author(s):  
Rui Guo ◽  
Rui Si ◽  
Brian T. Scott ◽  
Ayako Makino
Keyword(s):  
Endothelial Cells ◽  
Calcium Uptake ◽  
Vascular Endothelial Cells ◽  
Cyclopiazonic Acid ◽  
Mitochondrial Calcium ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Ros ◽  
Mitochondrial Functions ◽  
Store Operated Calcium Entry ◽  
Mitochondrial Calcium Uptake

Connexins (Cxs) are a group of integral membrane proteins that can form gap junctions between adjacent cells. Recently, it was reported that Cx43 is expressed not only in the plasma membrane but also in the inner mitochondrial membrane and that it regulates mitochondrial functions. Cx40 is predominantly expressed in vascular endothelial cells (ECs) and plays an important role in the electrical propagation between ECs and endothelial/smooth muscle cells. However, it is unknown whether Cx40 is expressed in the mitochondria and what the role of mitochondrial Cx40 is in endothelial functions. We observed in coronary ECs that Cx40 protein was expressed in the mitochondria, as determined by Western blot and immunofluorescence studies. We found that mouse coronary ECs (MCECs) isolated from Cx40 knockout (Cx40 KO) mice exhibited significantly lower resting mitochondrial calcium concentration ([Ca2+]mito) than MCECs from wild-type (WT) mice. After increase in cytosolic Ca2+ concentration ([Ca2+]cyto) with cyclopiazonic acid, calcium uptake into the mitochondria was significantly attenuated in MCECs from Cx40 KO mice compared with WT MCECs. There was no difference in resting [Ca2+]cyto and store-operated calcium entry in MCECs from WT and Cx40 KO mice. We also detected a significant decrease in the concentration of mitochondrial reactive oxygen species (ROS) in Cx40 KO MCECs. Cx40 overexpression in ECs significantly increased resting [Ca2+]mito level and calcium uptake by mitochondria in response to increased [Ca2+]cyto and augmented mitochondrial ROS production. These data suggest that mitochondrial Cx40 contributes to the regulation of mitochondrial calcium homeostasis.

scholarly journals Thrombin-mediated increases in cytosolic [Ca2+] involve different mechanisms in human pulmonary artery smooth muscle and endothelial cells

2008 ◽  
Vol 295 (6) ◽  
pp. L1048-L1055 ◽  
Author(s):  
Richard S. Sacks ◽  
Amy L. Firth ◽  
Carmelle V. Remillard ◽  
Negin Agange ◽  
Jocelyn Yau ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Calcium Influx ◽  
Dynamic Balance ◽  
Cyclopiazonic Acid ◽  
Cell Types ◽  
Intracellular Ca ◽  
Pulmonary Artery Smooth Muscle ◽  
Human Pulmonary Artery

Thrombin is a procoagulant inflammatory agonist that can disrupt the endothelium-lumen barrier in the lung by causing contraction of endothelial cells and promote pulmonary cell proliferation. Both contraction and proliferation require increases in cytosolic Ca2+ concentration ([Ca2+]cyt). In this study, we compared the effect of thrombin on Ca2+ signaling in human pulmonary artery smooth muscle (PASMC) and endothelial (PAEC) cells. Thrombin increased the [Ca2+]cyt in both cell types; however, the transient response was significantly higher and recovered quicker in the PASMC, suggesting different mechanisms may contribute to thrombin-mediated increases in [Ca2+]cyt in these cell types. Depletion of intracellular stores with cyclopiazonic acid (CPA) in the absence of extracellular Ca2+ induced calcium transients representative of those observed in response to thrombin in both cell types. Interestingly, CPA pretreatment significantly attenuated thrombin-induced Ca2+ release in PASMC; this attenuation was not apparent in PAEC, indicating that a PAEC-specific mechanism was targeted by thrombin. Treatment with a combination of CPA, caffeine, and ryanodine also failed to abolish the thrombin-induced Ca2+ transient in PAEC. Notably, thrombin-induced receptor-mediated calcium influx was still observed in PASMC after CPA pretreatment in the presence of extracellular Ca2+. Ca2+ oscillations were triggered by thrombin in PASMC resulting from a balance of extracellular Ca2+ influx and Ca2+ reuptake by the sarcoplasmic reticulum. The data show that thrombin induces increases in intracellular calcium in PASMC and PAEC with a distinct CPA-, caffeine-, and ryanodine-insensitive release existing only in PAEC. Furthermore, a dynamic balance between Ca2+ influx, intracellular Ca2+ release, and reuptake underlie the Ca2+ transients evoked by thrombin in some PASMC. Understanding of such mechanisms will provide an important insight into thrombin-mediated vascular injury during hypertension.

scholarly journals Cyclopiazonic Acid-Induced Ca2+ Store Depletion Initiates Endothelium-Dependent Hyperpolarization-Mediated Vasorelaxation of Mesenteric Arteries in Healthy and Colitis Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Lu Yun Zhang ◽  
Xiong Ying Chen ◽  
Hui Dong ◽  
Feng Xu
Keyword(s):  
Endothelial Cells ◽  
Channel Blocker ◽  
Vascular Endothelial Cells ◽  
Specific Inhibitor ◽  
Cyclopiazonic Acid ◽  
Blood Perfusion ◽  
Mesenteric Arteries ◽  
Measuring System ◽  
Flufenamic Acid ◽  
Store Operated Calcium Entry

Purposes: Since the role of store-operated calcium entry (SOCE) in endothelium-dependent hyperpolarization (EDH)-mediated vasorelaxation of mesenteric arteries in health and colitis is not fully understood, cyclopiazonic acid (CPA), a specific inhibitor of the sarco(endo) plasmic reticulum calcium-ATPases (SERCA), was used as a SOCE activator to investigate its role in normal mice and its alteration in colitis mice.Methods: The changes in Ca2+ signaling in vascular endothelial cells (VEC) were examined by single cell Ca2+ imaging and tension of mesenteric arteries in response to CPA were examined using Danish DMT520A microvascular measuring system.Results: CPA activated the SOCE through depletion of the endoplasmic reticulum (ER) Ca2+ in endothelial cells. CPA had a concentration-dependent vasorelaxing effect in endothelium-intact mesenteric arteries, which was lost after endothelial removal. Both nitric oxide (NO) and prostacyclin (PGI2) inhibitors did not affect CPA-induced vasorelaxation; however, after both NO and PGI2 were inhibited, KCa channel blocker [10 mM tetraethylammonium chloride (TEA)] inhibited CPA-induced vasorelaxation while KCa channel activator (0.3 μM SKA-31) promoted it. Two SOCE blockers [30 μM SKF96365 and 100 μM flufenamic acid (FFA)], and an Orai channel blocker (30 μM GSK-7975A) inhibited this vasorelaxation. The inhibition of both Na+/K+-ATPase (NKA) and Na+/Ca2+-exchange (NCX) also inhibited CPA-induced vasorelaxation. Finally, the CPA involved in EDH-induced vasorelaxation by the depletion of ER Ca2+ of mesenteric arteries was impaired in colitis mice.Conclusion: Depletion of ER Ca2+ by CPA induces a vasorelaxation of mesenteric arteries that is mediated through EDH mechanism and invokes the activation of SOCE. The CPA-induced endothelium-dependent dilation is impaired in colitis which may limit blood perfusion to the intestinal mucosa.

scholarly journals Endothelium Modulates Contractile Response to Simvastatin in Rat Aorta

2000 ◽  
Vol 55 (1-2) ◽  
pp. 121-124 ◽  
Author(s):  
Concepción Pérez-Guerrero ◽  
María Álvarez de Sotomayor ◽  
Maria Dolores Herrera ◽  
Elisa Marhuenda
Keyword(s):  
Endothelial Cells ◽  
Calcium Concentration ◽  
Contractile Response ◽  
Reductase Activity ◽  
Cyclopiazonic Acid ◽  
Rat Aorta ◽  
No Synthase ◽  
Response Curves ◽  
Hmgcoa Reductase ◽  
Coa Reductase

Simvastatin is an inhibitor of HMG -CoA reductase used in the treatment of hypercholesterolemia. In the present study simvastatin-induced contraction was observed in rat aortic thoracic rings, this effect increased when the endothelium was removed and when NO synthase was blocked by L-NOARG (3 x 10-5 ᴍ) . The contractile effect of simvastatin on intact aortic rings diminished when cyclo-oxygenase was inhibited with indomethacin (10-5 ᴍ). Also in the presence of endothelium, pretreatment with mevalonate (1 mM), the product of HMGCoA reductase activity, significantly inhibited the contraction. In other experiments carried out on endothelium-removed preparations and in medium containing the calcium antagonist, diltiazem (10-5 and 10-6 ᴍ) , the contraction dose-response curves were significantly reduced and the same happened in the presence of the inhibitor of sarcoplasmic reticulum Ca-2+- ATPase, cyclopiazonic acid (CPA) (3 x 10-6 ᴍ) . The results suggest that simvastatin might increase intracellular calcium concentration. This effect could lead to an activation of NO synthase and cyclooxygenase pathways in endothelial cells and to contraction in vascular smooth muscle cells. This rise in Ca2+ concentration could be due to an inhibition of isoprenoid synthesis prevented by mevalonate.

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