Ryanodine Receptor Regulates Endogenous Cannabinoid Mobilization in the Hippocampus

2006 ◽  
Vol 95 (5) ◽  
pp. 3001-3011 ◽  
Author(s):  
Masako Isokawa ◽  
Bradley E. Alger
Keyword(s):  
Ryanodine Receptor ◽  
Critical Role ◽  
Cyclopiazonic Acid ◽  
Pyramidal Cells ◽  
Gaba Release ◽  
Cytosolic Calcium ◽  
Ruthenium Red ◽  
Dependent Manner ◽  
Release Channel ◽  
Voltage Gated

Endogenous cannabinoids (eCBs) are produced and mobilized in a cytosolic calcium ([Ca2+]i)–dependent manner, and they regulate excitatory and inhibitory neurotransmitter release by acting as retrograde messengers. An indirect but real-time bioassay for this process on GABAergic transmission is DSI (depolarization-induced suppression of inhibition). The magnitude of DSI correlates linearly with depolarization-induced increase of [Ca2+]i that is thought to be initiated by Ca2+ influx through voltage-gated Ca2+ channels. However, the identity of Ca2+ sources involved in eCB mobilization in DSI remains undetermined. Here we show that, in CA1 pyramidal cells, DSI-inducing depolarizing voltage steps caused Ca2+-induced Ca2+ release (CICR) by activating the ryanodine receptor (RyR) Ca2+-release channel. CICR was reduced, and the remaining increase in [Ca2+]i was less effective in generating DSI, when the RyR antagonists, ryanodine or ruthenium red, were applied intracellularly, or the Ca2+ stores were depleted by the Ca2+-ATPase inhibitors, cyclopiazonic acid or thapsigargin. The CICR-dependent effects were most prominent in cultured or immature acute slices, but were also detectable in slices from adult tissue. Thus we suggest that voltage-gated Ca2+ entry raises local [Ca2+]i sufficiently to activate nearby RyRs and that the resulting CICR plays a critical role in initiating eCB mobilization. RyR may be a key molecule for the depolarization-induced production of eCBs that inhibit GABA release in the hippocampus.

scholarly journals Ca2+-Induced Ca2+ Release in the Pancreatic β-Cell: Direct Evidence of Endoplasmic Reticulum Ca2+ Release

Endocrinology ◽  
2003 ◽  
Vol 144 (8) ◽  
pp. 3565-3574 ◽  
Author(s):  
Thomas K. Graves ◽  
Patricia M. Hinkle
Keyword(s):  
Endoplasmic Reticulum ◽  
Ryanodine Receptor ◽  
Dependent Manner ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Release Channel ◽  
Voltage Gated ◽  
Carbamyl Choline ◽  
Dose Dependent

Abstract The role of the Ca2+-induced Ca2+ release channel (ryanodine receptor) in MIN6 pancreatic β-cells was investigated. An endoplasmic reticulum (ER)-targeted “cameleon” was used to report lumenal free Ca2+. Depolarization of MIN6 cells with KCl led to release of Ca2+ from the ER. This ER Ca2+ release was mimicked by treatment with the ryanodine receptor agonists caffeine and 4-chloro-m-cresol, reversed by voltage-gated Ca2+ channel antagonists and blocked by treatment with antagonistic concentrations of ryanodine. The depolarization-induced rise in cytoplasmic Ca2+ was also inhibited by ryanodine, which did not alter voltage-gated Ca2+ channel activation. Both ER and cytoplasmic Ca2+ changes induced by depolarization occurred in a dose-dependent manner. Glucose caused a delayed rise in cytoplasmic Ca2+ but no detectable change in ER Ca2+. Carbamyl choline caused ER Ca2+ release, a response that was not altered by ryanodine. Taken together, these results provide strong evidence that Ca2+-induced Ca2+ release augments cytoplasmic Ca2+ signals in pancreatic β-cells.

Characterization of the ryanodine receptor/channel of invertebrate muscle

1998 ◽  
Vol 274 (2) ◽  
pp. R494-R502 ◽  
Author(s):  
Kerry E. Quinn ◽  
Loriana Castellani ◽  
Karol Ondrias ◽  
Barbara E. Ehrlich
Keyword(s):  
Ryanodine Receptor ◽  
Single Channel ◽  
Microscopic Analysis ◽  
Ruthenium Red ◽  
Electron Microscopic ◽  
Release Channel ◽  
Single Channel Currents ◽  
Channel Currents ◽  
Bell Shaped Curve

Electron-microscopic analysis was used to show that invertebrate muscle has feetlike structures on the sarcoplasmic reticulum (SR) displaying the typical four-subunit appearance of the calcium (Ca2+) release channel/ryanodine receptor (RyR) observed in vertebrate skeletal muscle (K. E. Loesser, L. Castellani, and C. Franzini-Armstrong. J. Muscle Res. Cell Motil. 13: 161–173, 1992). SR vesicles from invertebrate muscle exhibited specific ryanodine binding and single channel currents that were activated by Ca2+, caffeine, and ATP and inhibited by ruthenium red. The single channel conductance of this invertebrate RyR was lower than that of the vertebrate RyR (49 and 102 pS, respectively). Activation of lobster and scallop SR Ca2+ release channel, in response to cytoplasmic Ca2+ (1 nM–10 mM), reflected a bell-shaped curve, as is found with the mammalian RyR. In contrast to a previous report (J.-H. Seok, L. Xu, N. R. Kramarcy, R. Sealock, and G. Meissner. J. Biol. Chem. 267: 15893–15901, 1992), our results show that regulation of the invertebrate and vertebrate RyRs is quite similar and suggest remarkably similar paths in these diverse organisms.

scholarly journals Modification of ryanodine receptor/Ca2+ release channel with dinitrofluorobenzene

1999 ◽  
Vol 342 (1) ◽  
pp. 239-248 ◽  
Author(s):  
Nurit HADAD ◽  
Wei FENG ◽  
Varda SHOSHAN-BARMATZ
Keyword(s):  
Ryanodine Receptor ◽  
Single Channel ◽  
Ruthenium Red ◽  
Amino Group ◽  
Channel Activity ◽  
Closed Channel ◽  
Release Channel ◽  
Atp Binding Site ◽  
Ph Values ◽  
Stimulation Of

Modification of the ryanodine receptor (RyR)/Ca2+ release channel with 2,4-dinitrofluorobenzene (DNFB) indicated that two classes of amino group interact with the reagent, as can be distinguished on the basis of their reactivity/accessibility and the effects on ryanodine binding and single channel activities. One group interacted very rapidly (t½ < 30 s) at 25 °C with low concentrations of DNFB [C50 (concentration of DNFB required for 50% inhibition or stimulation of ryanodine binding) = 5 μM], and at pH values of 6.2 and higher. This interaction resulted in the marked stimulation of ryanodine binding and the complete inhibition of a single Ca2+ release channel incorporated into planar lipid bilayer. The second group is accessible at higher temperatures (37 °C); at pH values higher than 7.4 it reacted slowly (t½ = 20 min) with high concentrations of DNFB (C50 = 70 μM). This interaction led to the inhibition of ryanodine binding and single channel activity. Modification of RyR with DNFB under the stimulatory conditions resulted in 3.6-fold and 6-fold increases in ryanodine-binding and Ca2+-binding affinities respectively. Modification with DNFB under the inhibitory conditions resulted in a decrease in the total ryanodine-binding sites. The exposure of the RyR single channel to DNFB under both inhibitory and stimulatory conditions led to the complete closure of the channel. However, when modified under the stimulatory conditions, but not under the inhibitory ones, the DNFB-modified closed channel could be re-activated by sub-micromolar concentrations of ryanodine, in the presence of nanomolar concentrations of Ca2+. The DNFB-modified ryanodine-activated RyR channel showed fast transitions between open, closed and several sub-conductance states, and was completely closed by Ruthenium Red. ATP re-activated the DNFB-modified closed channel or, if present during modification, prevented the inhibition of RyR channel activity by DNFB. Neither the stimulation nor the inhibition of ryanodine binding by modification with DNFB was affected by the presence of ATP. By using the photoreactive ATP analogue 3′-O-(4-benzoyl)benzoyl-[α-32P]ATP we found that DNFB modification had no effect on the ATP-binding site of RyR. The results are discussed with regard to the involvement of amino group residues in channel gating, ryanodine association/dissociation and occlusion, and the relationship between the open/closed state of the RyR and its capacity to bind ryanodine.

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 Retrograde transport of Akt by a neuronal Rab5-APPL1 endosome

2018 ◽  
Author(s):  
Livia Goto-Silva ◽  
Marisa P. McShane ◽  
Sara Salinas ◽  
Yannis Kalaidzidis ◽  
Giampietro Schiavo ◽  
...  
Keyword(s):  
Long Range ◽  
Critical Role ◽  
Primary Cultures ◽  
Pyramidal Cells ◽  
Retrograde Transport ◽  
Small Gtpase ◽  
Neurotrophin Receptor ◽  
Dependent Manner ◽  
Long Distance ◽  
Hippocampal Pyramidal Cells

AbstractLong-distance axonal trafficking plays a critical role in neuronal function, and transport defects have been linked to neurodegenerative disorders. Various lines of evidence suggest that the small GTPase Rab5 plays a role in neuronal signaling via early endosomal transport. Here, we characterized the motility of Rab5 endosomes in primary cultures of mouse hippocampal pyramidal cells by live-cell imaging and showed that they exhibit bi-directional long-range motility in axons, with a strong bias toward retrograde transport. Characterization of key Rab5 effectors revealed that endogenous Rabankyrin-5, Rabenosyn-5 and APPL1 are all present in axons. Further analysis of APPL1-positive endosomes showed that, similar to Rab5-endosomes, they display more frequent long-range retrograde than anterograde movement, with the endosomal levels of APPL1 correlated with faster retrograde movement. Interestingly, APPL1-endosomes transport the neurotrophin receptor TrkB and mediate retrograde axonal transport of the kinase Akt1. FRET analysis revealed that APPL1 and Akt1 interact in an endocytosis-dependent manner. We conclude that Rab5-APPL1 endosomes exhibit the hallmarks of axonal signaling endosomes to transport Akt1 in hippocampal pyramidal cells.

Carnosine is a novel peptide modulator of intracellular calcium and contractility in cardiac cells

1997 ◽  
Vol 272 (1) ◽  
pp. H462-H468 ◽  
Author(s):  
G. P. Zaloga ◽  
P. R. Roberts ◽  
K. W. Black ◽  
M. Lin ◽  
G. Zapata-Sudo ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Lipid Bilayers ◽  
Ryanodine Receptor ◽  
Calcium Release ◽  
Cardiac Contractility ◽  
Cardiac Cells ◽  
Dependent Manner ◽  
Calcium Release Channel ◽  
Release Channel ◽  
Contractile Failure

Myocardial contractile failure is a common cause of morbidity and mortality in patients with ischemic heart disease and systemic inflammatory states such as sepsis. Accumulating evidence indicates that contractile failure is associated with dysregulation of myoplasmic calcium levels. In a search for biochemical causes for contractile dysfunction, we found that the dipeptide carnosine improves cardiac contractility and tested the possibility that carnosine plays a role in the regulation of intracellular calcium. Carnosine increased contractility in a dose-dependent manner (1-10 mM) in isolated perfused rat hearts. and it also increased free intracellular calcium levels in isolated myocytes. Carnosine increased myocyte tension via calcium release from the ryanodine receptor calcium release channel in skinned myocardial fibers and increased open-state probability and dwell time of the isolated ryanodine receptor calcium release channel in lipid bilayers. In addition. we report that carnosine sensitizes the contractile proteins so calcium. These results suggest a novel role for carnosine as a modulator of intracellular calcium and contractility in cardiac tissue.

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.

scholarly journals Calmodulin sensitivity of the sarcoplasmic reticulum ryanodine receptor from normal and malignant-hyperthermia-susceptible muscle

1996 ◽  
Vol 319 (2) ◽  
pp. 421-426 ◽  
Author(s):  
Sean O'DRISCOLL ◽  
Tommie V. McCARTHY ◽  
Hans M. EICHINGER ◽  
Wolf ERHARDT ◽  
Frank LEHMANN-HORN ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Malignant Hyperthermia ◽  
Ryanodine Receptor ◽  
Central Region ◽  
Dependent Manner ◽  
Release Channel ◽  
Malignant Hyperthermia Susceptible ◽  
Potential Binding ◽  
Cam Regulation

Ca2+ release from sarcoplasmic reticulum (SR) of malignant-hyperthermia-susceptible (MHS) muscle is hypersensitive to Ca2+ and caffeine. To determine if an abnormal calmodulin (CaM) regulation of the SR Ca2+-release-channel-ryanodine-receptor complex (RYR1) contributes to this hypersensitivity, we investigated the effect of CaM on high-affinity [3H]ryanodine binding to isolated SR vesicles from normal and MHS pig skeletal muscle. CaM modulated [3H]ryanodine binding in a Ca2+-dependent manner. In the presence of maximally activating Ca2+ concentrations, CaM inhibited [3H]ryanodine binding with no differences between normal and MHS vesicles. In the absence of Ca2+, however, CaM activated [3H]ryanodine binding with a 2-fold-higher potency in MHS vesicles. Significant differences between normal and MHS tissue were observed for CaM concentrations between 50 nM and 10 µM. A polyclonal antibody raised against the central region of RYR1 specifically inhibited this activating effect of CaM without affecting the inhibition by CaM. This indicates that the central region of RYR1 is a potential binding domain for CaM in the absence of Ca2+. It is suggested that in vivo an enhanced CaM sensitivity of RYR1 might contribute to the abnormal high release of Ca2+ from the SR of MHS muscle.

scholarly journals Functional Effects of Central Core Disease Mutations in the Cytoplasmic Region of the Skeletal Muscle Ryanodine Receptor

2001 ◽  
Vol 118 (3) ◽  
pp. 277-290 ◽  
Author(s):  
Guillermo Avila ◽  
Robert T. Dirksen
Keyword(s):  
Skeletal Muscle ◽  
Ryanodine Receptor ◽  
Central Core ◽  
Central Core Disease ◽  
Calcium Release Channel ◽  
Release Channel ◽  
Voltage Gated ◽  
Channel Function ◽  
Store Depletion ◽  
The Impact

Central core disease (CCD) is a human myopathy that involves a dysregulation in muscle Ca2+ homeostasis caused by mutations in the gene encoding the skeletal muscle ryanodine receptor (RyR1), the protein that comprises the calcium release channel of the SR. Although genetic studies have clearly demonstrated linkage between mutations in RyR1 and CCD, the impact of these mutations on release channel function and excitation-contraction coupling in skeletal muscle is unknown. Toward this goal, we have engineered the different CCD mutations found in the NH2-terminal region of RyR1 into a rabbit RyR1 cDNA (R164C, I404M, Y523S, R2163H, and R2435H) and characterized the functional effects of these mutations after expression in myotubes derived from RyR1-knockout (dyspedic) mice. Resting Ca2+ levels were elevated in dyspedic myotubes expressing four of these mutants (Y523S &gt; R2163H &gt; R2435H R164C &gt; I404M RyR1). A similar rank order was also found for the degree of SR Ca2+ depletion assessed using maximal concentrations of caffeine (10 mM) or cyclopiazonic acid (CPA, 30 μM). Although all of the CCD mutants fully restored L-current density, voltage-gated SR Ca2+ release was smaller and activated at more negative potentials for myotubes expressing the NH2-terminal CCD mutations. The shift in the voltage dependence of SR Ca2+ release correlated strongly with changes in resting Ca2+, SR Ca2+ store depletion, and peak voltage–gated release, indicating that increased release channel activity at negative membrane potentials promotes SR Ca2+ leak. Coexpression of wild-type and Y523S RyR1 proteins in dyspedic myotubes resulted in release channels that exhibited an intermediate degree of SR Ca2+ leak. These results demonstrate that the NH2-terminal CCD mutants enhance release channel sensitivity to activation by voltage in a manner that leads to increased SR Ca2+ leak, store depletion, and a reduction in voltage-gated Ca2+ release. Two fundamentally distinct cellular mechanisms (leaky channels and EC uncoupling) are proposed to explain how altered release channel function caused by different mutations in RyR1 could result in muscle weakness in CCD.

scholarly journals Activation and labelling of the purified skeletal muscle ryanodine receptor by an oxidized ATP analogue

1995 ◽  
Vol 308 (1) ◽  
pp. 119-125 ◽  
Author(s):  
M Hohenegger ◽  
A Herrmann-Frank ◽  
M Richter ◽  
F Lehmann-Horn
Keyword(s):  
Skeletal Muscle ◽  
Ryanodine Receptor ◽  
Single Channel ◽  
Adenine Nucleotide ◽  
Nucleotide Binding ◽  
Binding Pocket ◽  
Hill Coefficient ◽  
Dependent Manner ◽  
Open Probability ◽  
Release Channel

We have tested the periodate-oxidized ATP analogue 2′,3′-dialdehyde adenosine triphosphate (oATP) as a ligand for the skeletal muscle ryanodine receptor/Ca(2+)-release channel. Ca2+ efflux from passively loaded heavy sarcoplasmic reticulum vesicles of skeletal muscle is biphasic. oATP stimulates the initial phase of Ca2+ release in a concentration-dependent manner (EC50 160 microM), and the efflux proceeds with a half-time in the range 100-200 ms. This oATP-modulated initial rapid Ca2+ release was specifically inhibited by millimolar concentrations of Mg2+ and micromolar concentrations of Ruthenium Red, indicating that the effect of oATP was mediated via the ryanodine receptor. The purified Ca(2+)-release channel was incorporated into planar lipid bilayers, and single-channel recordings were carried out to verify a direct interaction of oATP with the ryanodine receptor. Addition of oATP to the cytoplasmic side activated the channel with an EC50 of 76 microM, which is roughly 30-fold higher than the apparent affinity of ATP. The oATP-induced increase in the open probability of the ryanodine receptor displays a steep concentration-response curve with a Hill coefficient of approximately 2, which suggests a co-operativity of the ATP binding sites in the tetrameric protein. oATP binds to the ryanodine receptor in a quasi-irreversible manner via Schiff base formation between the aldehyde groups of oATP and amino groups in the nucleotide binding pocket. This allows for the covalent specific incorporation of [alpha-32P]oATP by borhydride reduction. A typical adenine nucleotide binding site cannot be identified in the primary sequence of the ryanodine receptor. Our results demonstrate that oATP can be used to probe the structure and function of the nucleotide binding pocket of the ryanodine receptor and presumably of other ATP-regulated ion channels.

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