scholarly journals Effect of adenine nucleotides on myo-inositol-1,4,5-trisphosphate-induced calcium release

1997 ◽  
Vol 325 (3) ◽  
pp. 661-666 ◽  
Author(s):  
Ludwig MISSIAEN ◽  
Jan B. PARYS ◽  
Humbert DE SMEDT ◽  
Ilse SIENAERT ◽  
Henk SIPMA ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Binding Site ◽  
Calcium Release ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Release Process ◽  
A7r5 Cells ◽  
Channel Opening ◽  
Inositol 1,4,5 Trisphosphate

The effects of a whole series of adenine nucleotides on Ins(1,4,5)P3-induced Ca2+ release were characterized in permeabilized A7r5 smooth-muscle cells. Several adenine nucleotides activated the Ins(1,4,5)P3 receptor. It was observed that 3′-phosphoadenosine 5′-phosphosulphate, CoA, di(adenosine-5′)tetraphosphate (Ap4A) and di(adenosine-5′)pentaphosphate (Ap5A) were more effective than ATP. Ap4A and Ap5A also interacted with a lower EC50 than ATP. In order to find out how these adenine nucleotides affected Ins(1,4,5)P3-induced Ca2+ release, we have measured their effect on the response of permeabilized A7r5 cells to a progressively increasing Ins(1,4,5)P3 concentration. Stimulatory ATP and Ap5A concentrations had no effect on the threshold Ins(1,4,5)P3 concentration for initiating Ca2+ release, but they stimulated Ca2+ release in the presence of supra-threshold Ins(1,4,5)P3 concentrations by increasing the co-operativity of the release process. Inhibition of the Ins(1,4,5)P3-induced Ca2+ release at higher ATP concentrations was associated with a further increase in co-operativity and also with a shift in threshold towards higher Ins(1,4,5)P3 concentrations. ATP had no effect on the non-specific Ca2+ leak in the absence of Ins(1,4,5)P3. We conclude that the adenine-nucleotide-binding site can be activated by many different adenine nucleotides. Binding of these compounds to the transducing domain of the Ins(1,4,5)P3 receptor increases the efficiency of transmitting Ins(1,4,5)P3 binding to channel opening. The inhibition by high ATP concentrations is exerted at a different site, related to Ins(1,4,5)P3 binding.

scholarly journals Inhibition of inositol trisphosphate-induced calcium release by cyclicADP-ribose in A7r5 smooth-muscle cells and in 16HBE14o- bronchial mucosal cells

1998 ◽  
Vol 329 (3) ◽  
pp. 489-495 ◽  
Author(s):  
Ludwig MISSIAEN ◽  
B. Jan PARYS ◽  
Humbert DE SMEDT ◽  
Ilse SIENAERT ◽  
Henk SIPMA ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Ryanodine Receptor ◽  
Calcium Release ◽  
Inositol Phosphates ◽  
Adenine Nucleotide ◽  
Regulatory Site ◽  
A7r5 Cells ◽  
Cyclic Adp Ribose ◽  
Mucosal Cells

Ca2+ release from intracellular stores occurs via two families of intracellular channels, each with their own specific agonist: Ins(1,4,5)P3 for the Ins(1,4,5)P3 receptor and cyclic ADP-ribose (cADPR) for the ryanodine receptor. We now report that cADPR inhibited Ins(1,4,5)P3-induced Ca2+ release in permeabilized A7r5 cells with an IC50 of 20 μM, and in permeabilized 16HBE14o- bronchial mucosal cells with an IC50 of 35 μM. This inhibition was accompanied by an increase in specific [3H]Ins(1,4,5)P3 binding. 8-Amino-cADPR, but not 8-bromo-cADPR, antagonized this effect of cADPR. The inhibition was prevented by a whole series of inositol phosphates (10 μM) that did not affect Ins(1,4,5)P3-induced Ca2+ release, and by micromolar concentrations of PPi and various nucleotide di- or triphosphates. We propose that cADPR must interact with a novel regulatory site on the Ins(1,4,5)P3 receptor or on an associated protein. This site is neither the Ins(1,4,5)P3-binding domain, which prefers Ins(1,4,5)P3 and only binds nucleotides and PPi in the millimolar range, nor the stimulatory adenine nucleotide binding site.

scholarly journals Effects of adenine nucleotides on inositol 1,4,5-trisphosphate-induced calcium release in vascular smooth muscle cells.

1991 ◽  
Vol 98 (4) ◽  
pp. 681-698 ◽  
Author(s):  
M Iino
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Calcium Release ◽  
Adenine Nucleotides ◽  
Muscle Cells ◽  
Release Mechanism ◽  
Maximal Effect ◽  
Competitive Antagonism ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca

Effects of adenine nucleotides on the inositol 1,4,5-trisphosphate (IP3)-induced Ca release (IICR) mechanism were studied in smooth muscle cells of the guinea pig portal vein. A microfluorometry method of fura-2 was used to measure Ca release from saponin-skinned thin muscle strips (width approximately 200 microns, thickness 50-70 microns, length 2-3 mm). About 80% of ionomycin-releasable Ca store was sensitive to IP3, of which approximately 20% was also sensitive to caffeine. The rate of Ca release by 0.1 microM IP3 depended biphasically on ATP concentration in the absence of Mg2+; it was dose-dependently enhanced by ATP up to approximately 0.5 mM, and above this concentration the enhancement became smaller. However, the decline of enhancement of the IICR at the higher ATP concentrations was absent at IP3 concentrations greater than 1 microM. This suggests competitive antagonism between IP3 and ATP. Clear effects of ATP were observed not only at pCa 7 or 8, where the Ca-induced Ca release was not activated, but after a ryanodine treatment to excise the functional compartment that possessed the Ca-induced Ca release mechanism. ATP had no effect on the rate of Ca leakage in the absence of IP3 even at pCa 5.5 after the ryanodine treatment. Therefore, ATP has direct biphasic effects on the IP3-induced Ca release mechanism. The Ca release induced by 0.1 microM IP3 at pCa 7 was potentiated not only by ATP, but by 0.5 mM ADP, AMP, or beta, gamma-methyleneadenosine 5'-triphosphate. 0.5 mM GTP had only a little effect on the IP3-induced Ca release. These results extend the functional similarities between Ca- and IP3-induced Ca release mechanisms in that adenine nucleotides enhance Ca release. Millimolar concentration of ATP, which is present physiologically, will shift the dose-response relation of IP3 toward the higher IP3 concentration and enhance the maximal effect of IP3. Thus, ATP is expected to assist the Ca release by higher concentrations of IP3 while having less effect on the Ca release by low levels of IP3. These effects of ATP may be important in the switching of Ca release from the intracellular Ca store by IP3.

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.

scholarly journals Inositol 1,4,5-trisphosphate activates TRPC3 channels to cause extracellular Ca2+ influx in airway smooth muscle cells

2015 ◽  
Vol 309 (12) ◽  
pp. L1455-L1466 ◽  
Author(s):  
Tengyao Song ◽  
Qiongyu Hao ◽  
Yun-Min Zheng ◽  
Qing-Hua Liu ◽  
Yong-Xiao Wang
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Binding Site ◽  
Airway Smooth Muscle ◽  
Muscle Cells ◽  
Airway Smooth Muscle Cells ◽  
Signaling Molecule ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Trpc3 Channel

Transient receptor potential-3 (TRPC3) channels play a predominant role in forming nonselective cation channels (NSCCs) in airway smooth muscle cells (ASMCs) and are significantly increased in their activity and expression in asthmatic ASMCs. To extend these novel findings, we have explored the regulatory mechanisms that control the activity of TRPC3 channels. Our data for the first time reveal that inositol 1,4,5-trisphosphate (IP3), an important endogenous signaling molecule, can significantly enhance the activity of single NSCCs in ASMCs. The analog of diacylglycerol (DAG; another endogenous signaling molecule), 1-oleyl-2-acetyl- sn-glycerol (OAG), 1-stearoyl-2-arachidonoyl- sn-glycerol (SAG), and 1-stearoyl-2-linoleoyl- sn-glycerol (SLG) all augment NSCC activity. The effects of IP3 and OAG are fully abolished by lentiviral short-hairpin (sh)RNA-mediated TRPC3 channel knockdown (KD). The stimulatory effect of IP3 is eliminated by heparin, an IP3 receptor (IP3R) antagonist that blocks the IP3-binding site, but not by xestospongin C, the IP3R antagonist that has no effect on the IP3-binding site. Lentiviral shRNA-mediated KD of IP3R1, IP3R2, or IP3R3 does not alter the excitatory effect of IP3. TRPC3 channel KD greatly inhibits IP3-induced increase in intracellular Ca2+ concentration. IP3R1 KD produces a similar inhibitory effect. TRPC3 channel and IP3R1 KD both diminish the muscarinic receptor agonist methacholine-evoked Ca2+ responses. Taking these findings together, we conclude that IP3, the important intracellular second messenger, may activate TRPC3 channels to cause extracellular Ca2+ influx, in addition to opening IP3Rs to induce intracellular Ca2+ release. This novel extracellular Ca2+ entry route may play a significant role in mediating IP3-mediated numerous cellular responses in ASMCs and other cells.

Norepinephrine transport by the extraneuronal monoamine transporter in human bronchial arterial smooth muscle cells

2003 ◽  
Vol 285 (4) ◽  
pp. L829-L837 ◽  
Author(s):  
Gabor Horvath ◽  
Zoltan Sutto ◽  
Aliza Torbati ◽  
Gregory E. Conner ◽  
Matthias Salathe ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Mrna Expression ◽  
Binding Site ◽  
Membrane Binding ◽  
Muscle Cells ◽  
Arterial Smooth Muscle ◽  
Extraneuronal Monoamine Transporter ◽  
Arterial Smooth Muscle Cells ◽  
Specific Membrane

Inhaled glucocorticosteroids (GSs) cause acute, α1-adrenoreceptor (AR)-mediated bronchial vasoconstriction. After release from sympathetic nerves, norepinephrine (NE) must be taken up into cells for deactivation by intracellular enzymes. Because postsynaptic cellular NE uptake is steroid sensitive, GSs could increase NE concentrations at α1-AR, causing vasoconstriction. We therefore evaluated mRNA expression of different NE transporters in human bronchial arterial smooth muscle and pharmacologically characterized NE uptake into these cells. RT-PCR demonstrated mRNA expression of the extraneuronal monoamine transporter (EMT) and organic cation transporter 1 (OCT-1). Fluorometric uptake assay showed time (within minutes)- and concentration-dependent NE uptake by freshly isolated bronchial arterial smooth muscle cells (SMC) with an estimated Km of 240 μM. Corticosterone and O-methylisoprenaline (1 μM each), but not desipramine, inhibited NE uptake, a profile indicative of NE uptake by EMT, but not OCT-1. Budesonide and methylprednisolone inhibited uptake with IC50 values of 0.9 and 5.6 μM, respectively. Corticosterone's action was reversible and not sensitive to RU-486 (GS receptor antagonist), actinomycin D (transcription inhibitor), or cycloheximide (protein synthesis inhibitor). Corticosterone made membrane impermeant by coupling to BSA also blocked NE uptake. Immunocytochemistry indicated a specific membrane binding site for corticosterone on bronchial arterial SMC. These data demonstrate that although human bronchial arterial SMC express OCT-1 and EMT, EMT is the predominant plasma membrane transporter for NE uptake. This process can be inhibited by GSs, likely via a specific membrane binding site. This nongenomic GS action (increasing NE concentrations at α1-AR) could explain acute bronchial vasoconstriction caused by inhaled GSs.

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