Ruthenium red selectively prevents Ins(1,4,5)P3-but not caffeine-gated calcium release in avian atrium

1992 ◽  
Vol 262 (1) ◽  
pp. H268-H277 ◽  
Author(s):  
A. M. Vites ◽  
A. J. Pappano
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Present Report ◽  
Ruthenium Red ◽  
Detectable Effect ◽  
Calcium Accumulation ◽  
Two Agents ◽  
Release Mechanisms ◽  
Subsequent Response ◽  
Inositol 1,4,5 Trisphosphate

We previously reported that inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and caffeine evoked contractures in saponin-permeabilized chick atria. The magnitude of contractures evoked by maximally effective concentrations of Ins(1,4,5)P3 were half those evoked by maximally effective concentrations of caffeine. In the present report, we tested the hypothesis that these two agents may act on distinct calcium-release mechanisms by comparing the effects of ryanodine, ruthenium red, and procaine on the responses to Ins(1,4,5)P3 and caffeine. We find that procaine inhibits both responses with similar mean inhibitory concentrations in the millimolar range. Nanomolar concentrations of ryanodine selectively potentiate the contractures induced by Ins(1,4,5)P3 but have no effect on those induced by caffeine. Micromolar concentrations of ryanodine inhibit responses to both Ins(1,4,5)P3 and caffeine in a use-dependent way. Ruthenium red prevents the response to Ins(1,4,5)P3 and potentiates that to caffeine, as if ruthenium red had enhanced calcium accumulation in the caffeine-sensitive pool(s). Because we found that caffeine prevented the subsequent response to Ins(1,4,5)P3, but Ins(1,4,5)P3 had no detectable effect on the caffeine-induced contracture, we conclude that Ins(1,4,5)P3 and caffeine act on pharmacologically distinct calcium-release mechanisms that may reside in the same sarcoplasmic reticulum compartment.

scholarly journals The Effect of Calcium Ionophores on Fragmented Sarcoplasmic Reticulum

1972 ◽  
Vol 60 (6) ◽  
pp. 735-749 ◽  
Author(s):  
Antonio Scarpa ◽  
Judith Baldassare ◽  
Giuseppe Inesi
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Binding ◽  
Calcium Release ◽  
Atp Hydrolysis ◽  
Divalent Cations ◽  
Electron Microscopic ◽  
Microscopic Appearance ◽  
Calcium Accumulation ◽  
Calcium Dependent ◽  
Dependent Atpase

X-537 A and A 23187, two antibiotics which form liphophilic complexes with divalent cations, function as ionophores in vesicular fragments of sarcoplasmic reticulum (SR). Addition of either ionophore to SR preloaded with calcium in the presence of adenosine triphosphate (ATP), causes rapid release of calcium. Furthermore, net calcium accumulation by SR is prevented, when the ionophores are added to the reaction mixture before ATP. On the contrary, ATP-independent calcium binding to SR is not inhibited. This effect is specific for the two antibiotics and could not be reproduced, either by inactive derivatives, or by other known ionophores. Neither ionophore produces alterations of the electron microscopic appearance of SR membranes or inhibition of the calcium-dependent ATPase. In fact, the burst of ATP hydrolysis obtained on addition of calcium, is prolonged in the presence of the ionophores. Lanthanum inhibits ATP-independent calcium binding to SR, ATP-dependent calcium accumulation and calcium-dependent ATPase. However, addition of lanthanum to SR preloaded in the presence of ATP, does not cause calcium release. The reported experiments indicated that: (a) ATP-dependent calcium accumulation by SR results in primary formation of calcium ion gradients across the membrane. (b) Most of the accumulated calcium is not available for displacement by lanthanum on the outer surface of the membrane. (c) Calcium ionophores induce rapid equilibration of the gradients, by facilitating cation diffusion across the membrane.

Cooling and pH jump-induced calcium release from isolated cardiac sarcoplasmic reticulum

1994 ◽  
Vol 267 (3) ◽  
pp. H962-H969
Author(s):  
J. J. Feher ◽  
I. M. Rebeyka
Keyword(s):  
Steady State ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Order Rate Constant ◽  
Ruthenium Red ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Rapid Cooling ◽  
Ph Jump ◽  
Steady State Levels ◽  
Efflux Pathway

Rapid-cooling contracture in cardiac muscle preparations is thought to be caused by the release of Ca2+ from the sarcoplasmic reticulum (SR), but the mechanism of this release is unknown. Cooling of isolated canine cardiac SR from 37 to 4 degrees C resulted in the net release of enough Ca2+ to account for rapid-cooling contracture. The release of Ca2+ on cooling appeared to be a relaxation between different steady-state levels of Ca2+ uptake. Cooling release of Ca2+ was also observed in the presence of ryanodine or ruthenium red to block the ryanodine-sensitive Ca2+ efflux pathway. In the presence of ryanodine, the extent and initial rate of rapid-cooling release were increased due to increased steady-state uptake of Ca2+ by the SR. The first-order rate constant of rapid-cooling Ca2+ release was unchanged by ryanodine or ruthenium red, suggesting that the rapid-cooling release does not occur through the ryanodine-sensitive pathway. The alkalinization on cooling was not the major cause of the Ca2+ release, as comparable Ca2+ release was observed with cooling and no alkalinization. However, alkalinization without cooling produced a rapid net Ca2+ release, which was also observed in the presence of ryanodine.

Luminal calcium regulation of calcium release from sarcoplasmic reticulum

1995 ◽  
Vol 15 (5) ◽  
pp. 387-397 ◽  
Author(s):  
Cecilia Hidalgo ◽  
Paulina Donoso
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Concentration ◽  
Calcium Release ◽  
Single Channel ◽  
Release Rates ◽  
Calcium Release Channels ◽  
Channel Opening ◽  
Inositol 1,4,5 Trisphosphate ◽  
Luminal Calcium ◽  
Trisphosphate Receptor

This article discusses how changes in luminal calcium concentration affect calcium release rates from triad-enriched sarcoplasmic reticulum vesicles, as well as single channel opening probability of the ryanodine receptor/calcium release channels incorporated in bilayers. The possible participation of calsequestrin, or of other luminal proteins of sarcoplasmic reticulum in this regulation is addressed. A comparison with the regulation by luminal calcium of calcium release mediated by the inositol 1,4,5-trisphosphate receptor/calcium channel is presented as well.

scholarly journals Sphingosylphosphocholine modulates the ryanodine receptor/calcium-release channel of cardiac sarcoplasmic reticulum membranes

1997 ◽  
Vol 322 (1) ◽  
pp. 327-333 ◽  
Author(s):  
Romeo BETTO ◽  
Alessandra TERESI ◽  
Federica TURCATO ◽  
Giovanni SALVIATI ◽  
Roger A. SABBADINI ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Ryanodine Receptor ◽  
Calcium Release ◽  
Cardiac Tissue ◽  
Ruthenium Red ◽  
Release Mechanism ◽  
Calcium Release Channel ◽  
Release Channel ◽  
Cardiac Sarcoplasmic Reticulum ◽  
High Calcium

Sphingosylphosphocholine (SPC) modulates Ca2+ release from isolated cardiac sarcoplasmic reticulum membranes; 50 ƁM SPC induces the release of 70Ő80% of the accumulated calcium. SPC releases calcium from cardiac sarcoplasmic reticulum through the ryanodine receptor, since the release is inhibited by the ryanodine receptor channel antagonists ryanodine, Ruthenium Red and sphingosine. In intact cardiac myocytes, even in the absence of extracellular calcium, SPC causes a rise in diastolic Ca2+, which is greatly reduced when the sarcoplasmic reticulum is depleted of Ca2+ by prior thapsigargin treatment. SPC action on the ryanodine receptor is Ca2+-dependent. SPC shifts to the left the Ca2+-dependence of [3H]ryanodine binding, but only at high pCa values, suggesting that SPC might increase the sensitivity to calcium of the Ca2+-induced Ca2+-release mechanism. At high calcium concentrations (pCa 4.0 or lower), where [3H]ryanodine binding is maximally stimulated, no effect of SPC is observed. We conclude that SPC releases calcium from cardiac sarcoplasmic reticulum membranes by activating the ryanodine receptor and possibly another intracellular Ca2+-release channel, the sphingolipid Ca2+-release-mediating protein of endoplasmic reticulum (SCaMPER) [Mao, Kim, Almenoff, Rudner, Kearney and Kindman (1996) Proc. Natl. Acad. Sci. U.S.A 93, 1993Ő1996], which we have identified for the first time in cardiac tissue.

scholarly journals Patterns of sarcomere activation, temperature dependence, and effect of ryanodine in chemically skinned cardiac fibers.

1986 ◽  
Vol 87 (6) ◽  
pp. 885-905 ◽  
Author(s):  
A Lundblad ◽  
H Gonzalez-Serratos ◽  
G Inesi ◽  
J Swanson ◽  
P Paolini
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Temperature Dependence ◽  
Calcium Release ◽  
Contractile Activity ◽  
The Other ◽  
Calcium Blockers ◽  
Calcium Accumulation ◽  
Contractile Activation

Functionally skinned and electrochemically shunted myocytes were prepared by perfusing rat hearts with collagenase in order to obtain a technically improved measurement of sarcomere dynamics and to evaluate the role of sarcoplasmic reticulum in situ with respect to contractile activation. In the presence of micromolar calcium, the myocytes exhibited phasic and propagated contraction waves beginning at one end and proceeding along the myocyte. Beating rates, the propagation velocity of the activation wave, and single sarcomere shortening and relaxation velocities were obtained by manual or automated analysis of 16-mm film recorded at 170 frames/s from a camera attached to a microscope that was equipped with a temperature-controlled stage. In parallel experiments, calcium accumulation by the sarcoplasmic reticulum of the myocytes in situ was measured by direct isotopic tracer methods. The frequency (10-38 min-1) of spontaneous contractions, the velocity (1.9-7.4 microns . s-1) of sarcomere shortening, and the velocity (1.7-6.8 microns . s-1) of sarcomere relaxation displayed identical temperature dependences (Q10 = 2.2), which are similar to that of the calcium pump of sarcoplasmic reticulum and are consistent with a rate limit imposed by enzyme-catalyzed mechanisms on all these parameters. On the other hand, the velocity (77-159 microns . s-1) of sequential sarcomere activation displayed a lower temperature dependence (Q10 = 1.5), which is consistent with a diffusion-limited and self-propagating release of calcium from one sarcomere to the other. The phasic contractile activity of the dissociated myocytes was inhibited by 10(-8)-10(6) M ryanodine (and not by myolemmal calcium blockers) under conditions in which calcium accumulation by sarcoplasmic reticulum in situ was demonstrated to proceed optimally. The effect of ryanodine is attributed to an interaction of this drug with sarcotubular structures, producing inhibition of calcium release from the sarcoplasmic reticulum. The consequent lack of sarcomere activation underlines the role of sarcoplasmic reticulum uptake and release in the phasic contractile activation of the electrochemically shunted myocytes.

scholarly journals Purified ryanodine receptor from rabbit skeletal muscle is the calcium-release channel of sarcoplasmic reticulum.

1988 ◽  
Vol 92 (1) ◽  
pp. 1-26 ◽  
Author(s):  
J S Smith ◽  
T Imagawa ◽  
J Ma ◽  
M Fill ◽  
K P Campbell ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Ryanodine Receptor ◽  
Calcium Release ◽  
Binding Capacity ◽  
Ruthenium Red ◽  
Rabbit Skeletal Muscle ◽  
Permeability Ratio ◽  
Calcium Release Channel ◽  
Release Channel

The ryanodine receptor of rabbit skeletal muscle sarcoplasmic reticulum was purified as a single 450,000-dalton polypeptide from CHAPS-solubilized triads using immunoaffinity chromatography. The purified receptor had a [3H]ryanodine-binding capacity (Bmax) of 490 pmol/mg and a binding affinity (Kd) of 7.0 nM. Using planar bilayer recording techniques, we show that the purified receptor forms cationic channels selective for divalent ions. Ryanodine receptor channels were identical to the Ca-release channels described in native sarcoplasmic reticulum using the same techniques. In the present work, four criteria were used to establish this identity: (a) activation of channels by micromolar Ca and millimolar ATP and inhibition by micromolar ruthenium red, (b) a main channel conductance of 110 +/- 10 pS in 54 mM trans Ca, (c) a long-term open state of lower unitary conductance induced by ryanodine concentrations as low as 20 nM, and (d) a permeability ratio PCa/PTris approximately equal to 14. In addition, we show that the purified ryanodine receptor channel displays a saturable conductance in both monovalent and divalent cation solutions (gamma max for K and Ca = 1 nS and 172 pS, respectively). In the absence of Ca, channels had a broad selectivity for monovalent cations, but in the presence of Ca, they were selectively permeable to Ca against K by a permeability ratio PCa/PK approximately equal to 6. Receptor channels displayed several equivalent conductance levels, which suggest an oligomeric pore structure. We conclude that the 450,000-dalton polypeptide ryanodine receptor is the Ca-release channel of the sarcoplasmic reticulum and is the target site of ruthenium red and ryanodine.

Nitric oxide inhibits calcium release from sarcoplasmic reticulum of porcine tracheal smooth muscle cells

1997 ◽  
Vol 272 (1) ◽  
pp. L1-L7 ◽  
Author(s):  
M. S. Kannan ◽  
Y. S. Prakash ◽  
D. E. Johnson ◽  
G. C. Sieck
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Ryanodine Receptors ◽  
Tracheal Smooth Muscle ◽  
Nitric Oxide Donor ◽  
Ip3 Receptors ◽  
Video Fluorescence Microscopy ◽  
Inositol 1,4,5 Trisphosphate

In the present study, effects of the nitric oxide donor, S-nitroso-N-acetylpenicillamine (SNAP), on sarcoplasmic reticulum (SR) Ca2+ release were examined in freshly dissociated porcine tracheal smooth muscle (TSM) cells. Fura 2-loaded TSM cells were imaged using video fluorescence microscopy. SR Ca2+ release was induced by acetylcholine (ACh), which acts principally through inositol 1,4,5-trisphosphate (IP3) receptors, and by caffeine, which acts principally through ryanodine receptors (RyR). SNAP inhibited ACh-induced SR Ca2+ release at both 0 and 2.5 mM extracellular Ca2+. Degraded SNAP had no effect on ACh-induced SR Ca2+ release. SNAP also inhibited caffeine-induced SR Ca2+ release. ACh-induced Ca2+ influx was not affected by SNAP when SR reloading was blocked by thapsigargin. SNAP also did not affect SR Ca2+ reuptake. The membrane-permeant analogue of guanosine 3',5'-cyclic monophosphate (cGMP), 8-bromo-cGMP, mimicked the effects of SNAP. These results suggest that, in porcine TSM cells, SNAP reduces the intracellular Ca2+ response to ACh and caffeine by inhibiting SR Ca2+ release through both IP3 and RyR, but not by inhibiting influx or repletion of the SR Ca2+ stores. These effects are likely mediated via cGMP-dependent mechanisms.

Characterization of Ca2+ release from heterogeneous Ca2+ stores in sarcoplasmic reticulum isolated from arterial and gastric smooth muscle

2002 ◽  
Vol 80 (6) ◽  
pp. 588-603 ◽  
Author(s):  
Marguerite A Stout ◽  
Luc Raeymaekers ◽  
Humbert De Smedt ◽  
Rik Casteels
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Slow Component ◽  
Main Pulmonary Artery ◽  
Adenosine Diphosphate ◽  
Ruthenium Red ◽  
Gastric Antrum ◽  
Gastric Smooth Muscle ◽  
Inositol 1,4,5 Trisphosphate ◽  
Cyclic Adenosine Diphosphate

Ca2+ transport was investigated in vesicles of sarcoplasmic reticulum subfractionated from bovine main pulmonary artery and porcine gastric antrum using digitonin binding and zonal density gradient centrifugation. Gradient fractions recovered at 15–33% sucrose were studied as the sarcoplasmic reticulum component using Fluo-3 fluorescence or 45Ca2+ Millipore filtration. Thapsigargin blocked active Ca2+ uptake and induced a slow Ca2+ release from actively loaded vesicles. Unidirectional 45Ca2+ efflux from passively loaded vesicles showed multicompartmental kinetics. The time course of an initial fast component could not be quantitatively measured with the sampling method. The slow release had a half-time of several minutes. Both components were inhibited by 20 μM ruthenium red and 10 mM Mg2+. Caffeine, inositol 1,4,5-trisphosphate, ATP, and diltiazem accelerated the slow component. A Ca2+ release component activated by ryanodine or cyclic adenosine diphosphate ribose was resolved with Fluo-3. Comparison of tissue responses showed that the fast Ca2+ release was significantly smaller and more sensitive to inhibition by Mg2+ and ruthenium red in arterial vesicles. They released more Ca2+ in response to inositol 1,4,5-trisphosphate and were more sensitive to activation by cyclic adenosine diphosphate ribose. Ryanodine and caffeine, in contrast, were more effective in gastric antrum. In each tissue, the fraction of the Ca+2 store released by sequential application of caffeine and inositol 1,4,5-trisphosphate depended on the order applied and was additive. The results indicate that sarcoplasmic reticulum purified from arterial and gastric smooth muscle represents vesicle subpopulations that retain functional Ca2+ channels that reflect tissue-specific pharmacological modulation. The relationship of these differences to physiological responses has not been determined.Key words: calcium channels, smooth muscle, sarcoplasmic reticulum.

scholarly journals Calcium pools mobilized by calcium or inositol 1,4,5-trisphosphate are differentially localized in rat heart and brain.

1992 ◽  
Vol 3 (6) ◽  
pp. 621-631 ◽  
Author(s):  
A Verma ◽  
D J Hirsch ◽  
S H Snyder
Keyword(s):  
Binding Sites ◽  
Calcium Release ◽  
Cardiac Tissue ◽  
Coronary Vessels ◽  
Medial Septum ◽  
Ruthenium Red ◽  
Cardiac Conduction ◽  
Inositol 1,4,5 Trisphosphate ◽  
Calcium Induced Calcium Release ◽  
The Brain

Calcium-induced calcium release (CICR) pools have been demonstrated in brain and heart microsomes biochemically and autoradiographically by the sensitivity of 45Ca2+ accumulation to Mg2+, ATP, ruthenium red, caffeine, and tetracaine. The CICR pool colocalizes with [3H]ryanodine binding sites, supporting the notion that [3H]ryanodine labels CICR pools. Sites of CICR pools in the brain contrast with those of inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ pools with reciprocal localizations between the two Ca2+ pools in several structures. Thus, in the hippocampus CA-1 is enriched in IP3-sensitive Ca2+ pools, whereas CICR pools are highest in CA-3 and the dentate gyrus. The corpus striatum and cerebellum are enriched in IP3 pools, whereas the medial septum and olfactory bulb have high CICR densities. In cardiac tissue, CICR is localized to atrial and ventricular muscle, whereas IP3 pools are concentrated in coronary vessels and cardiac conduction fibers. The reciprocal enrichment of IP3 and CICR Ca2+ pools implies differential regulation of Ca2+ hemostasis in these tissues.

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