Calcium ATPase in the sarcoplasmic reticulum of muscle from normal and malignant hyperthermia susceptible pigs

1991 ◽  
Vol 131 (2) ◽  
pp. 187-192
Author(s):  
Angela F. Dulhunty ◽  
Pauline R. Junankar ◽  
Carolyn Stanhope
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Malignant Hyperthermia ◽  
Calcium Atpase ◽  
Malignant Hyperthermia Susceptible

Caffeine stimulation of malignant hyperthermia-susceptible sarcoplasmic reticulum Ca2+ release channel

1994 ◽  
Vol 267 (5) ◽  
pp. C1253-C1261 ◽  
Author(s):  
N. H. Shomer ◽  
J. R. Mickelson ◽  
C. F. Louis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Malignant Hyperthermia ◽  
Single Channel ◽  
Release Channel ◽  
Muscle Contracture ◽  
Malignant Hyperthermia Susceptible ◽  
Open Time ◽  
Pig Muscle ◽  
Channel Mutation ◽  
The Difference

The altered caffeine sensitivity of malignant hyperthermia-susceptible (MHS) muscle contracture is one basis of the diagnostic test for this syndrome. To determine whether the Arg615-to-Cys615 mutation of the porcine sarcoplasmic reticulum (SR) Ca2+ release channel is directly responsible for this altered caffeine sensitivity, the single-channel kinetics of purified MHS and normal pig Ca2+ release channels were examined. Initial studies demonstrated that decreasing the pH of the medium in either the cis- or trans-chamber decreased the Ca2+ release channel percent open time (Po). The half-inhibitory pH of MHS channels (6.86 +/- 0.04, n = 17) was significantly different from that of normal channels (7.08 +/- 0.07, n = 14). At pH 7.4, in either 7 or 0.12 microM Ca2+, MHS channel Po was not significantly different from that of normal channels over the range 0-10 mM caffeine. Although at pH 6.8 in 7 microM Ca2+ MHS channel Po was greater than that of normal channels over the range 0-20 mM caffeine, the difference could be eliminated by dividing each mean MHS Po by a scaling factor of 3.2. Thus the MHS Ca2+ release channel mutation does not appear to be directly responsible for the altered caffeine sensitivity of MHS pig muscle contracture. Rather, this altered caffeine sensitivity may result from an altered resting myoplasmic Ca2+ concentration or the altered pH and Ca2+ sensitivity of Ca2+ release channel Po of MHS muscle.

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.

Analysis of lipid composition of sarcoplasmic reticulum membranes from normal and malignant hyperthermic pig skeletal muscle

1993 ◽  
Vol 71 (7-8) ◽  
pp. 324-330 ◽  
Author(s):  
Mohamed Sidi Mammar ◽  
Xavier Vignon ◽  
Edmond Rock ◽  
Frederique Mathieu ◽  
Gilles Gandemer
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Malignant Hyperthermia ◽  
Cholesterol Content ◽  
Fatty Acyl ◽  
Malignant Hyperthermia Susceptibility ◽  
Potential Consequence ◽  
Malignant Hyperthermia Susceptible ◽  
Acyl Chains ◽  
Pig Muscle ◽  
Membrane Defect

In search of a general membrane defect hypothesis for malignant hyperthermia syndrome, we analysed the lipid profiles of heavy sarcoplasmic reticulum membranes isolated from normal and malignant hyperthermia longissimus dorsi pig muscle. Malignant hyperthermia susceptibility was assessed by halothane challenge of pigs. Sarcoplasmic reticulum membranes from malignant hyperthermia susceptible pigs differed significantly from control ones in the cholesterol content and phosphatidylethanolamine/phosphatidylcholine ratio; both were higher in former membranes. These latter lipid modifications were in agreement with the significant increase of their bulk lipid viscosity, as evidenced by an increase of diphenyl hexatriene fluorescence anisotropy. The increased level of phosphatidylethanolamine associated with the decreased content of phosphatidylcholine in malignant hyperthermic membranes was shown to be a potential consequence of depressed activities of both phospholipid N-methyltransferase I and II activities. Finally, the distribution of fatty acids in these particular phospholipids showed no change in phosphatidylcholine molecules, whereas the percentage of arachidonate and stearate in the phosphatidylethanolamine species were respectively higher and lower in malignant hyperthermic membranes. These differences in major phospholipids content and the enrichment of a metabolically important fatty acyl chains in malignant hyperthermia sarcoplasmic reticulum membranes strongly suggest that the lipid metabolism may contribute to the molecular mechanism of malignant hyperthermia syndrome.Key words: malignant hyperthermia, sacroplasmic reticulum, ryanodine, phospholipid N-methyltransferase, fluidity.

Chlorocresol, an Additive to Commercial Succinylcholine, Induces Contracture of Human Malignant Hyperthermia-susceptible Muscles Via Activation of the Ryanodine Receptor Calcium sup 2+ Channel

1996 ◽  
Vol 84 (6) ◽  
pp. 1380-1385 ◽  
Author(s):  
Vincenzo Tegazzin ◽  
Erica Scutari ◽  
Susan Treves ◽  
Francesco Zorzato
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Malignant Hyperthermia ◽  
Muscle Relaxants ◽  
Commercial Preparation ◽  
Muscle Contracture ◽  
Malignant Hyperthermia Susceptible ◽  
Underlying Causes ◽  
Muscle Biopsies ◽  
Terminal Cisternae

Background A defect in the ryanodine (Ry1) receptor Ca2+ channel has been implicated as one of the possible underlying causes of malignant hyperthermia (MH), a pharmacogenetic disorder characterized by sustained muscle contracture. The disease is triggered by common halogenated anesthetics and skeletal muscle relaxants, such as succinylcholine. This study tested whether the functional properties of the Ry1 receptor Ca2+ channel are affected by chlorocresol, a preservative added to a commercial preparation of succinylcholine (Midarine) and other parenteral compounds. Methods In vitro contracture testing was carried out on muscle biopsies from malignant hyperthermia-susceptible (MHS) and -negative (MHN) individual according to the protocol of the European MH group. Ca2+ flux studies on isolated rabbit sarcoplasmic reticulum fractions were measured spectrophotometrically by following the A710-790 of the Ca2+ indicator antipyrylazo III. Results Chlorocresol causes muscle contracture in MHS muscles at a concentration of 25-50 microM and potentiates the caffeine contracture response in human MHS muscles. Sub-threshold (20 microM) concentrations of chlorocresol increase both the Kd and the Vmax of caffeine-induced Ca2+ release from isolated rabbit terminal cisternae. Conclusions These data suggest that, in muscle from MHS individuals, the enhanced Ca2+ released from the sarcoplasmic reticulum may not be due to the effect of succinylcholine alone but rather to the action of the preservative chlorocresol added to the drug.

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