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dc.creatorHIDALGO,CECILIA
dc.creatorARACENA,PAULA
dc.creatorSANCHEZ,GINA
dc.creatorDONOSO,PAULINA
dc.date2002-01-01
dc.date.accessioned2019-05-02T21:21:05Z
dc.date.available2019-05-02T21:21:05Z
dc.identifierhttps://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000200009
dc.identifier.urihttp://revistaschilenas.uchile.cl/handle/2250/81412
dc.descriptionIn skeletal and cardiac muscle cells, specific isoforms of the Ryanodine receptor channels mediate Ca2+ release from the sarcoplasmic reticulum. These channels are highly susceptible to redox modifications, which regulate channel activity. In this work, we studied the effects of Ca2+ (endogenous agonist) and Mg2+ (endogenous inhibitor) on the kinetics of Ca2+ release from sarcoplasmic reticulum vesicles isolated from skeletal or cardiac mammalian muscle. Native skeletal vesicles exhibited maximal stimulation of release kinetics by 10-20 µM [Ca2+], whereas in native cardiac vesicles, maximal stimulation of release required only 1 µM [Ca2+]. In 10 µM [Ca2+], free [Mg2+] < 0.1 mM produced marked inhibition of release from skeletal vesicles but free [Mg2+] ­ 0.8 mM did not affect release from cardiac vesicles. Incubation of skeletal or cardiac vesicles with the oxidant thimerosal increased their susceptibility to stimulation by Ca2+ and decreased the inhibitory effect of Mg2+ in skeletal vesicles. Sulfhydryl-reducing agents fully reversed the effects of thimerosal. The endogenous redox species, glutathione disulfide and S-nitrosoglutathione, also stimulated release from skeletal sarcoplasmic reticulum vesicles. In 10 µM [Ca2+], 35S-nitrosoglutathione labeled a protein fraction enriched in release channels through S-glutathiolation. Free [Mg2+] 1 mM or decreasing free [Ca2+] to the nM range prevented this reaction. Possible physiological and pathological consequences of redox modification of release channels on Ca2+ signaling in heart and muscle cells are discussed
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dc.languageen
dc.publisherSociedad de Biología de Chile
dc.relation10.4067/S0716-97602002000200009
dc.rightsinfo:eu-repo/semantics/openAccess
dc.sourceBiological Research v.35 n.2 2002
dc.subjectRedox state
dc.subjectRyanodine receptors
dc.subjectsarcoplasmic reticulum
dc.subjectcalcium release kinetics
dc.subjectMg2+ inhibition
dc.subjectS-nitrosoglutathione
dc.titleRedox regulation of calcium release in skeletal and cardiac muscle


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