Two mechanisms for termination of individual Ca2+ sparks in skeletal muscle

AUTOR(ES)

Lacampagne, Alain

FONTE

The National Academy of Sciences

RESUMO

Ca2+ sparks are brief, localized elevations of myoplasmic [Ca2+] caused by release of increments of Ca2+ via sarcoplasmic reticulum Ca2+ release channels in muscle. The properties of individual sparks provide information regarding the opening of sarcoplasmic reticulum Ca2+ channels within functioning cells. Here we use high-speed confocal microscopy to show that individual Ca2+ sparks activated by membrane depolarization in single frog skeletal muscle fibers can be terminated prematurely by repolarization. Thus, either voltage sensor deactivation on repolarization or release channel inactivation during continued depolarization can terminate the Ca2+ release channel activity underlying voltage-activated Ca2+ sparks in skeletal muscle.

Documentos Relacionados

• Small event Ca2+ release: a probable precursor of Ca2+ sparks in frog skeletal muscle.
• Sarcoplasmic reticulum Ca2+ release flux underlying Ca2+ sparks in cardiac muscle
• Low-Affinity Ca2+ Indicators Compared in Measurements of Skeletal Muscle Ca2+ Transients
• Rapid Ca2+ flux through the transverse tubular membrane, activated by individual action potentials in mammalian skeletal muscle
• Ca2+ sparks involving multiple Ca2+ release sites along Z-lines in rat heart cells.