PulseExploreJournal ClubResearchersJournals
Instagram
HomeJournal ClubExplore
Synapse
⌘+K
Synapse
September 1, 2000AJP Cell Physiology

Differential Ca2+sensitivity of skeletal and cardiac muscle ryanodine receptors in the presence of calmodulin

View Full Paper
Ask AI
Bookmark
Share

Population

Porcine skeletal muscle and cardiac sarcoplasmic reticulum (SR) vesicles

Comparison

Calmodulin in media containing 100 nM Ca vs Absence of CaM

Design

Preclinical

Key result

Calmodulin increased the rate of Ca(2+) release from porcine skeletal muscle SR vesicles approximately threefold, but did not affect cardiac SR vesicle Ca(2+) release.

Authors

BFBradley R. FruenJBJennifer M. BardyTBTodd M. Byrem

Discussion

Loading...

Member takes

Overview

Caution against extrapolating skeletal findings to cardiac Ca2+ handling; leaves open RyR isoform differences in human models.

Key Points

  • This research investigates how calmodulin influences calcium release from the ryanodine receptors in skeletal and cardiac muscle.
  • Utilized porcine skeletal muscle and cardiac muscle SR vesicles for Ca2+ release measurements.
  • Conducted (45)Ca2+ release assays in the presence of varying concentrations of calmodulin.
  • Performed cross-linking and binding experiments to assess CaM interactions with RyR1 and RyR2.
  • Skeletal muscle SR showed a threefold increase in (45)Ca2+ release with 1 μM CaM at 100 nM Ca2+ concentration.
  • Cardiac muscle SR exhibited no significant change in (45)Ca2+ release with CaM under similar conditions.
  • RyR1 demonstrated approximately sixfold increased calcium sensitivity regarding [(3)H]ryanodine binding, while RyR2 did not show a significant difference.

Structured PICO

P
Population
Porcine skeletal muscle and cardiac sarcoplasmic reticulum (SR) vesicles
I
Intervention
Calmodulin (CaM) (1 microM) in media containing 100 nM Ca(2+)
C
Comparator
Absence of CaM
O
Outcome
Rate of (45)Ca(2+) release and Ca(2+) sensitivity of [(3)H]ryanodine bindingsurrogate

Calmodulin activates skeletal muscle RyR1 by increasing its Ca2+ sensitivity but does not similarly activate cardiac RyR2, highlighting functional differences in Ca2+ dependence between the two isoforms.

Cite This Study

Fruen et al. (2000) studied this question. Calmodulin (CaM) vs. Absence of CaM was evaluated on Rate of (45)Ca(2+) release from SR vesicles. Calmodulin increased the rate of Ca(2+) release from porcine skeletal muscle SR vesicles approximately threefold, but did not affect cardiac SR vesicle Ca(2+) release.

synapsesocial.com/papers/6a20500e7a3568d6afd1eba0https://doi.org/10.1152/ajpcell.2000.279.3.c724
View Full Paper
Ask AI
Bookmark
Share