Consulta: subjectFacets:"Skeletal and cardiac muscle"
Registros recuperados: 2
Data/hora: 04/06/2024 00:41:52

SH Oxidation Stimulates Calcium Release Channels (Ryanodine Receptors) From Excitable Cells
Provedor de dados: Biological Research
Autores: HIDALGO,CECILIA; BULL,RICARDO; MARENGO,JUAN J; PÉREZ,CLAUDIO F; DONOSO,PAULINA.
The effects of redox reagents on the activity of the intracellular calcium release channels (ryanodine receptors) of skeletal and cardiac muscle, or brain cortex neurons, was examined. In lipid bilayer experiments, oxidizing agents (2,2'-dithiodipyridine or thimerosal) modified the calcium dependence of all single channels studied. After controlled oxidation channels became active at sub &amp;micro;M calcium concentrations and were not inhibited by increasing the calcium concentration to 0.5 mM. Subsequent reduction reversed these effects. Channels purified from amphibian skeletal muscle exhibited the same behavior, indicating that the SH groups responsible for modifying the calcium dependence belong to the channel protein. Parallel experiments that...
Tipo: Journal article
Palavras-chave: Calcium dependence; Neurons; Redox state; Ryanodine receptors; Sarcoplasmic reticulum; Skeletal and cardiac muscle.
Ano: 2000
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200011

Fast kinetics of calcium dissociation from calsequestrin
Provedor de dados: Biological Research
Autores: BELTRÁN,MARIANELA; BARRIENTOS,GENARO; HIDALGO,CECILIA.
We measured the kinetics of calcium dissociation from calsequestrin in solution or forming part of isolated junctional sarcoplasmic reticulum membranes by mixing calsequestrin equilibrated with calcium with calcium-free solutions in a stopped-flow system. In parallel, we measured the kinetics of the intrinsic fluorescence changes that take place following calcium dissociation from calsequestrin. We found that at 25ºC calcium dissociation was 10-fold faster for calsequestrin attached to junctional membranes (k = 109 s-1) than in solution. These results imply that calcium dissociation from calsequestrin in vivo is not rate limiting during excitation-contraction coupling. In addition, we found that the intrinsic fluorescence decrease for calsequestrin in...
Tipo: Journal article
Palavras-chave: Calcium-binding proteins; Ryanodine receptors; Sarcoplasmic reticulum; Calcium release kinetics; Excitation-contraction coupling; Skeletal and cardiac muscle.
Ano: 2006
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300011