Intra‐ and extraluminal sarcoplasmic reticulum membrane regulatory sites for Ca2+‐induced Ca2+ release
- 24 April 1990
- journal article
- Published by Wiley in FEBS Letters
- Vol. 263 (2) , 292-294
- https://doi.org/10.1016/0014-5793(90)81396-6
Abstract
A heavy skeletal muscle sarcoplasmic reticulum (SR) fraction was actively loaded stepwise with calcium until Ca2+‐induced Ca2+ release occurred. The total Ca2+ load, T1, at which release occurred is postulated to be regulated by an intraluminal, low‐affinity receptor. After obtaining T1, the critical concentration of Ca2+ required extraluminally (T2) was determined. T1 averaged 58.6 ± S.D., 6.9 nmol Ca2+/mg SR and T2 averaged 2.14 ± S.D., 0.24,μM. Both T1 and T2 were increased by Mg2+ and decreased by caffeine. Ruthenium red increased T2 more than T1 while ryanodine had no effect on T1 but markedly increased T2. The results suggest that two Ca2+ regulatory sites may be functional for Ca2+‐induced Ca2+ release from SR.Keywords
This publication has 9 references indexed in Scilit:
- Primary structure and expression from complementary DNA of skeletal muscle ryanodine receptorNature, 1989
- Does muscle activation occur by direct mechanical coupling of transverse tubules to sarcoplasmic reticulum?Trends in Biochemical Sciences, 1989
- Pharmacology of calcium release from sarcoplasmic reticulumJournal of Bioenergetics and Biomembranes, 1989
- The muscle ryanodine receptor and its intrinsic Ca2+ channel activityJournal of Bioenergetics and Biomembranes, 1989
- Kinetic analysis of excitation-contraction couplingJournal of Bioenergetics and Biomembranes, 1989
- Abnormality in calcium release from skeletal sarcoplasmic reticulum of pigs susceptible to malignant hyperthermia.Journal of Clinical Investigation, 1983
- Mechanism of calcium release from skeletal sarcoplasmic reticulumThe Journal of Membrane Biology, 1982
- Calcium release from the sarcoplasmic reticulumPhysiological Reviews, 1977
- Conditions Required for Calcium-Induced Release of Calcium from the Sarcoplasmic ReticulumProceedings of the Japan Academy, 1975