The sarcoplasmic reticulum of skeletal muscle is a specialized form of endoplasmic reticulum that controls myoplasmic calcium concentration and, therefore, the contraction-relaxation cycle. Ultrastructural studies have shown that the sarcoplasmic reticulum is a continuous but heterogeneous membranous network composed of longitudinal tubules that surround myofibrils and terminal cisternae. These cisternae are junctionally associated, via bridging structures called 'feet', with sarcolemmal invaginations (the transverse tubules) to form the triadic junction. Following transverse tubule depolarization, a signal, transmitted along the triadic junction, triggers Ca2+ release from terminal cisternae, but the mechanism of this coupling is still unknown. Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) has recently been shown to mobilize Ca2+ from intracellular stores, referable to endoplasmic reticulum, in a variety of cell types (see ref. 8 for review), including smooth muscle cells of the porcine coronary artery and canine cardiac muscle cells. Here we show that Ins(1,4,5)P3 releases Ca2+ from isolated, purified sarcoplasmic reticulum fractions of rabbit fast-twitch skeletal muscle, the effect being more pronounced on a fraction of terminal cisternae that contains morphologically intact feet structures; and elicits isometric force development in chemically skinned muscle fibres.

Inositol 1,4,5-trisphosphate induces calcium release from sarcoplasmic reticulum of skeletal muscle

VOLPE, POMPEO;POZZAN, TULLIO
1985

Abstract

The sarcoplasmic reticulum of skeletal muscle is a specialized form of endoplasmic reticulum that controls myoplasmic calcium concentration and, therefore, the contraction-relaxation cycle. Ultrastructural studies have shown that the sarcoplasmic reticulum is a continuous but heterogeneous membranous network composed of longitudinal tubules that surround myofibrils and terminal cisternae. These cisternae are junctionally associated, via bridging structures called 'feet', with sarcolemmal invaginations (the transverse tubules) to form the triadic junction. Following transverse tubule depolarization, a signal, transmitted along the triadic junction, triggers Ca2+ release from terminal cisternae, but the mechanism of this coupling is still unknown. Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) has recently been shown to mobilize Ca2+ from intracellular stores, referable to endoplasmic reticulum, in a variety of cell types (see ref. 8 for review), including smooth muscle cells of the porcine coronary artery and canine cardiac muscle cells. Here we show that Ins(1,4,5)P3 releases Ca2+ from isolated, purified sarcoplasmic reticulum fractions of rabbit fast-twitch skeletal muscle, the effect being more pronounced on a fraction of terminal cisternae that contains morphologically intact feet structures; and elicits isometric force development in chemically skinned muscle fibres.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/105711
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact