Stretch-induced Ca2+ release via an IP3-insensitive Ca2+ channel

2002 ◽  
Vol 283 (2) ◽  
pp. C456-C462 ◽  
Author(s):  
Madhumita Jena Mohanty ◽  
Xingli Li
Keyword(s):  
Smooth Muscle ◽  
Nicotinic Acid ◽  
Vascular Smooth Muscle Cells ◽  
Mechanical Stimulation ◽  
Ruthenium Red ◽  
Cytochalasin D ◽  
Mechanical Stimuli ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Cyclical Stretch

Various mechanical stimuli increase the intracellular Ca2+ concentration ([Ca2+]i) in vascular smooth muscle cells (VSMC). A part of the increase in [Ca2+]i is due to the release of Ca2+ from intracellular stores. We have investigated the effect of mechanical stimulation produced by cyclical stretch on the release of Ca2+ from the intracellular stores. Permeabilized VSMC loaded with45Ca2+ were subjected to 7.5% average (15% maximal) cyclical stretch. This resulted in an increase in45Ca2+ rate constant by 0.126 ± 0.0035. Inhibition of inositol 1,4,5-trisphosphate (IP3), ryanodine, and nicotinic acid adenine dinucleotide phosphate channels (NAADP) with 50 μg/ml heparin, 50 μM ruthenium red, and 25 μM thio-NADP, respectively, did not block the increase in45Ca2+ efflux in response to cyclical stretch. However, 10 μM lanthanum, 10 μM gadolinium, and 10 μM cytochalasin D but not 10 μM nocodazole inhibited the increase in45Ca2+ efflux. This supports the existence of a novel stretch-sensitive intracellular Ca2+ store in VSMC that is distinct from the IP3-, ryanodine-, and NAADP-sensitive stores.

Hypotonic swelling-induced Ca2+ release by an IP3-insensitive Ca2+ store

2001 ◽  
Vol 281 (2) ◽  
pp. C555-C562 ◽  
Author(s):  
Madhumita Jena Mohanty ◽  
Maian Ye ◽  
Xingli Li ◽  
Noreen F. Rossi
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Nicotinic Acid ◽  
Vascular Smooth Muscle Cells ◽  
Ruthenium Red ◽  
A7r5 Cells ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Hypotonic Swelling

Hypotonic swelling increases the intracellular Ca2+ concentration ([Ca2+]i) in vascular smooth muscle cells (VSMC). The source of this Ca2+ is not clear. To study the source of increase in [Ca2+]i in response to hypotonic swelling, we measured [Ca2+]i in fura 2-loaded cultured VSMC (A7r5 cells). Hypotonic swelling produced a 40.7-nM increase in [Ca2+]i that was not inhibited by EGTA but was inhibited by 1 μM thapsigargin. Prior depletion of inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ stores with vasopressin did not inhibit the increase in [Ca2+]i in response to hypotonic swelling. Exposure of 45Ca2+-loaded intracellular stores to hypotonic swelling in permeabilized VSMC produced an increase in45Ca2+ efflux, which was inhibited by 1 μM thapsigargin but not by 50 μg/ml heparin, 50 μM ruthenium red, or 25 μM thio-NADP. Thus hypotonic swelling of VSMC causes a release of Ca2+ from the intracellular stores from a novel site distinct from the IP3-, ryanodine-, and nicotinic acid adenine dinucleotide phosphate-sensitive stores.

Ets-1 is an early response gene activated by ET-1 and PDGF-BB in vascular smooth muscle cells

1998 ◽  
Vol 274 (2) ◽  
pp. C472-C480 ◽  
Author(s):  
Shinji Naito ◽  
Shunichi Shimizu ◽  
Shigeto Maeda ◽  
Jianwei Wang ◽  
Richard Paul ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Inositol Phosphate ◽  
Muscle Cells ◽  
Tetraacetic Acid ◽  
Acetoxymethyl Ester ◽  
Intracellular Ca

Ets-1 is a transcription factor that activates expression of matrix-degrading proteinases such as collagenase and stromelysin. To study the control of ets-1 gene expression in rat vascular smooth muscle cells (VSMC), cells were exposed to factors known to regulate VSMC migration and proliferation. Platelet-derived growth factor-BB (PDGF-BB), endothelin-1 (ET-1), and phorbol 12-myristate 13-acetate (PMA) induced a dose-dependent expression of ets-1 mRNA. These effects were abrogated by inhibition of protein kinase C (PKC) by H-7 or chronic PMA treatment. Ets-1 mRNA was superinduced by PDGF-BB and ET-1 in the presence of cycloheximide. The chelation of intracellular Ca2+ by 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-acetoxymethyl ester and the depletion of endoplasmic reticulum intracellular Ca2+concentration ([Ca2+]i) by thapsigargin inhibited PDGF-BB- and ET-1-induced ets-1 mRNA, whereas ethylene glycol-bis(β-aminoethyl ether)- N, N, N′, N′-tetraacetic acid had no effect. However, [Ca2+]irelease alone was not sufficient to increase ets-1 mRNA. Forskolin blocked ET-1-, PDGF-BB-, and PMA-induced ets-1 mRNA, as well as inositol phosphate formation, consistent with an effect through impairment of PKC activation. Inhibitors of ets-1 gene expression, such as H-7 and herbimycin A, inhibited the ET-1 induction of collagenase I mRNA. We propose that ets-1 may be an important element in the orchestration of matrix proteinase expression and of vascular remodeling after arterial injury.

Role of cyclic ADP-ribose in the regulation of [Ca2+]i in porcine tracheal smooth muscle

1998 ◽  
Vol 274 (6) ◽  
pp. C1653-C1660 ◽  
Author(s):  
Y. S. Prakash ◽  
Mathur S. Kannan ◽  
Timothy F. Walseth ◽  
Gary C. Sieck
Keyword(s):  
Smooth Muscle ◽  
Second Messenger ◽  
Ruthenium Red ◽  
Tracheal Smooth Muscle ◽  
Cyclic Adp Ribose ◽  
Intracellular Ca ◽  
Subsequent Exposure ◽  
Trisphosphate Receptor ◽  
Dose Dependent Increase

The purpose of the present study was to determine whether cyclic ADP-ribose (cADPR) acts as a second messenger for Ca2+ release through ryanodine receptor (RyR) channels in tracheal smooth muscle (TSM). Freshly dissociated porcine TSM cells were permeabilized with β-escin, and real-time confocal microscopy was used to examine changes in intracellular Ca2+ concentration ([Ca2+]i). cADPR (10 nM–10 μM) induced a dose-dependent increase in [Ca2+]i, which was blocked by the cADPR receptor antagonist 8-amino-cADPR (20 μM) and by the RyR blockers ruthenium red (10 μM) and ryanodine (10 μM), but not by the inositol 1,4,5-trisphosphate receptor blocker heparin (0.5 mg/ml). During steady-state [Ca2+]ioscillations induced by acetylcholine (ACh), addition of 100 nM and 1 μM cADPR increased oscillation frequency and decreased peak-to-trough amplitude. ACh-induced [Ca2+]ioscillations were blocked by 8-amino-cADPR; however, 8-amino-cADPR did not block the [Ca2+]iresponse to a subsequent exposure to caffeine. These results indicate that cADPR acts as a second messenger for Ca2+ release through RyR channels in TSM cells and may be necessary for initiating ACh-induced [Ca2+]ioscillations.

Effect of halothane on intracellular calcium oscillations in porcine tracheal smooth muscle cells

1999 ◽  
Vol 276 (1) ◽  
pp. L81-L89 ◽  
Author(s):  
Christina M. Pabelick ◽  
Y. S. Prakash ◽  
Mathur S. Kannan ◽  
Keith A. Jones ◽  
David O. Warner ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Ryanodine Receptor ◽  
Muscle Cells ◽  
Calcium Oscillations ◽  
Tracheal Smooth Muscle ◽  
Permeabilized Cells ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Trisphosphate Receptor

The effect of halothane on intracellular Ca2+ concentration ([Ca2+]i) regulation in porcine tracheal smooth muscle cells was examined with real-time confocal microscopy. Both 1 and 2 minimum alveolar concentration (MAC) halothane increased basal [Ca2+]iwhen Ca2+ influx and efflux were blocked, suggesting increased sarcoplasmic reticulum (SR) Ca2+ leak and/or decreased reuptake. In β-escin-permeabilized cells, heparin inhibition of inositol 1,4,5-trisphosphate-receptor channels blunted the halothane-induced increase in [Ca2+]i. Both 1 and 2 MAC halothane decreased the frequency and amplitude of ACh-induced [Ca2+]ioscillations (which represent SR Ca2+ release through ryanodine-receptor channels), abolishing oscillations in ∼20% of tracheal smooth muscle cells at 2 MAC. When Ca2+ influx and efflux were blocked, halothane increased the baseline and decreased the frequency and amplitude of [Ca2+]ioscillations, inhibiting oscillations in ∼70% of cells at 2 MAC. The fall time of [Ca2+]ioscillations and the rate of fall of the [Ca2+]iresponse to caffeine were both increased by halothane. These results suggest that halothane abolishes agonist-induced [Ca2+]ioscillations by 1) depleting SR Ca2+ via increased Ca2+ leak through inositol 1,4,5-trisphosphate-receptor channels, 2) decreasing Ca2+ release through ryanodine-receptor channels, and 3) inhibiting reuptake.

Regulation of hypoxia-inducible factor-1α by cyclical mechanical stretch in rat vascular smooth muscle cells

2003 ◽  
Vol 105 (4) ◽  
pp. 447-456 ◽  
Author(s):  
Hang CHANG ◽  
Kou-Gi SHYU ◽  
Bao-Wei WANG ◽  
Peiliang KUAN
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Map Kinase ◽  
Mechanical Stress ◽  
Vascular Smooth Muscle Cells ◽  
Hypoxia Inducible Factor ◽  
Mechanical Stretch ◽  
Cyclical Stretch ◽  
Map Kinase Kinase

Vascular smooth muscle cells (VSMCs) are exposed to hormonal and mechanical stress in vivo. Hormonal factors have been shown to affect hypoxia-inducible factor-1α (HIF-1α). How mechanical stress affects the regulation of HIF-1α in VSMCs has not been reported previously, and therefore we sought to investigate the regulation of HIF-1α by cyclical mechanical stretch in cultured rat VSMCs. Rat VSMCs grown on a flexible membrane base were stretched by vacuum to 20% of the maximum elongation at 60 cycles/min. The levels of HIF-1α protein began to increase as early as 2 h after stretch was applied and reached a maximum of 2.8-fold over the control by 4 h. Real-time PCR showed that the levels of HIF-1α mRNA increased 2.1-fold after cyclical stretch for 4 h. Cyclical mechanical stretch also increased the immunohistochemical labelling of HIF-1α in VSMCs after cyclical stretch for 4 h. The phosphorylation of p42/p44 mitogen-activated protein kinase (MAP kinase) increased after stretch and this was inhibited by the MAP kinase kinase inhibitors PD98059 and U0126. PD98059 and U0126 also blocked HIF-1α gene expression induced by cyclical stretch. In conclusion, cyclical mechanical stretch activates the gene expression of HIF-1α in cultured VSMCs and this mechanical effect is possibly mediated by the p42/p44 MAP kinase kinase pathway.

Attenuation of the serotonin-induced increase in intracellular calcium in rat aortic smooth muscle cells by sarpogrelate

2003 ◽  
Vol 81 (11) ◽  
pp. 1056-1063 ◽  
Author(s):  
Harjot K Saini ◽  
Sushil K Sharma ◽  
Peter Zahradka ◽  
Hideo Kumamoto ◽  
Nobuakira Takeda ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Dependent Manner ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Receptor Sites ◽  
Intracellular Ca

Although serotonin (5-HT) induced proliferation of vascular smooth muscle cells is considered to involve changes in intracellular Ca2+ ([Ca2+]i), the mechanism of Ca2+ mobilization by 5-HT is not well defined. In this study, we examined the effect of 5-HT on rat aortic smooth muscle cells (RASMCs) by Fura-2 microfluorometry for [Ca2+]i measurements. 5-HT was observed to increase the [Ca2+]i in a concentration- and time-dependent manner. This action of 5-HT was dependent upon the extracellular concentration of Ca2+ ([Ca2+]e) and was inhibited by both Ca2+ channel antagonists (verapamil and diltiazem) and inhibitors of sarcoplasmic reticular Ca2+ pumps (thapsigargin and cyclopia zonic acid). The 5-HT-induced increase in [Ca2+]i was blocked by sarpogrelate, a 5-HT2A-receptor antagonist, but not by different agents known to block other receptor sites. 5-HT-receptor antagonists such as ketanserin, cinanserin, and mianserin, unlike methysergide, were also found to inhibit the 5-HT-induced Ca2+ mobilization, but these agents were less effective in comparison to sarpogrelate. On the other hand, the increase in [Ca2+]i in RASMCs by ATP, angiotensin II, endothelin-1, or phorbol ester was not affected by sarpogrelate. These results indicate that Ca2+ mobilization in RASMCs by 5-HT is mediated through the activation of 5-HT2A receptors and support the view that the 5-HT-induced increase in [Ca2+]i involves both the extracellular and intracellular sources of Ca2+.Key words: sarpogrelate, serotonin, vascular smooth muscle cells, intracellular Ca2+.

Thapsigargin stimulates Ca2+ entry in vascular smooth muscle cells: nicardipine-sensitive and -insensitive pathways

1992 ◽  
Vol 262 (5) ◽  
pp. C1258-C1265 ◽  
Author(s):  
Y. T. Xuan ◽  
O. L. Wang ◽  
A. R. Whorton
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Inositol Polyphosphate ◽  
Inositol Polyphosphates ◽  
Permeabilized Cells ◽  
Inositol 1,4,5 Trisphosphate

We have investigated the role of the sarcoplasmic reticulum Ca2+ pool in regulating Ca2+ entry in vascular smooth muscle cells using a receptor-independent means of mobilizing the intracellular Ca2+ pool. Thapsigargin (TG) has been shown to inhibit the endoplasmic reticulum Ca(2+)-ATPase, mobilize intracellular Ca2+, and activate Ca2+ entry in nonmuscle tissues. When smooth muscle cells were treated with 0.2 microM TG, cytosolic Ca2+ concentrations rose gradually over 8 min to a peak value of 365 +/- 18 nM. Cytosolic Ca2+ remained elevated for at least 20 min and was supported by continued entry of extracellular Ca2+. TG also stimulated entry of Mn2+ and 45Ca2+ from outside the cell. Importantly, TG-induced Ca2+ entry and Mn2+ entry were found to occur through mechanisms that were independent of L-type Ca2+ channel activation because influx was not inhibited by concentrations of nicardipine that were found to block either endothelin- or 100 mM extracellular K(+)-induced cation influx. The mechanism through which TG activates cation entry appears to involve mobilization of the inositol 1,4,5-trisphosphate-responsive intracellular Ca2+ pool. In permeabilized cells, TG prevented ATP-stimulated Ca2+ uptake into the sarcoplasmic reticulum and slowly released sequestered Ca2+. The Ca2+ pool involved was responsive to inositol 1,4,5-trisphosphate. However, TG did not initiate the formation of inositol polyphosphates. Thus TG mobilizes the sarcoplasmic reticulum Ca2+ pool and activates Ca2+ entry through a nicardipine-insensitive Ca2+ channel in vascular smooth muscle. The mechanism is independent of inositol polyphosphate formation.

Sign in / Sign up

Export Citation Format

Share Document