Regulation of Skeletal Muscle Ca2+ Release Channel (Ryanodine Receptor) by Ca2+ and Monovalent Cations and Anions

Abstract

The effects of ionic composition and strength on rabbit skeletal muscle Ca 2؉ release channel (ryanodine receptor) activity were investigated in vesicle- 45

Biphasic modulation of ryanodine binding to sarcoplasmic reticulum vesicles of skeletal muscle by Zn2+ ions

“…As shown previously [3], in the absence of Zn# + the binding expressed a bell-shaped dependence on [Ca# + ] f and was increased significantly by 10 mM caffeine, especially at low [Ca# + ] f ( Figure 5). …”

“…It has been shown that the function of RyR1s can be modulated by various endogenous and exogenous factors, including caffeine, Mg# + and adenine nucleotide [2][3][4][5]. It is thought that caffeine increases the apparent affinity of the activation site for Ca# + , whereas Mg# + inhibits ryanodine binding by competing with Ca# + for the Ca# + activation site [3,4].…”

“…A ligand that can increase the binding usually causes an opening of RyR1s. An advantage of the [$H]ryanodine binding assay is that it permits the assessment of the effect of various ionic conditions [3,9]. To have more understanding about the effect of Zn# + on Ca# + release from SR, the effect of Zn# + on…”

“…It has been shown that the function of RyR1s can be regulated by various endogenous and exogenous factors, including several univalent and bivalent ions [2][3][4][5]. Among the bivalent cations, the effects of Ca# + and Mg# + are well known [3,4].…”

“…As a convenient method, a [$H]ryanodine binding assay has been used to investigate the effect of various agents on the function of RyR1s [2][3][4][5]. A close correlation between ryanodine binding and the gating state of RyR1s has been established for many ligands of RyR1s [2], although there are a few exceptions [4,8].…”