What question did this study set out to answer?

To characterize calcium fluxes and functional properties of isolated junctional terminal cisternae compared to light sarcoplasmic reticulum, heavy sarcoplasmic reticulum, and triads from fast skeletal muscle.

December 16, 1986Biochemistry

Functional characterization of junctional terminal cisternae from mammalian fast skeletal muscle sarcoplasmic reticulum

Q: What is the clinical evidence from this study?

Study design: Other. Intervention: Junctional terminal cisternae vs. Light and heavy sarcoplasmic reticulum and isolated triads. Primary outcome: Ca2+ fluxes and transport.

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Key result

Junctional terminal cisternae exhibit decreased Ca2+ transport driven by enhanced permeability from localized release channels.

Population

Mammalian fast skeletal muscle sarcoplasmic reticulum fractions

Comparison

Ruthenium red, high [Mg2+], or ryanodine vs Untreated fractions or comparison between…

Design

Preclinical

Authors

ACAlice ChuEmory University PVPompeo VolpeElectrophysiology BCBrian CostelloRutgers, The State University of New Jersey

Discussion

Member takes

Implication

May inform SR Ca2+ channel targeting in myopathies; leaves open translation from animal biochemistry to human cardiac function.

Key Points

To characterize calcium fluxes and functional properties of isolated junctional terminal cisternae compared to light sarcoplasmic reticulum, heavy sarcoplasmic reticulum, and triads from fast skeletal muscle.
Isolated junctional terminal cisternae containing junctional face membranes and calcium pump membranes alongside light sarcoplasmic reticulum, heavy sarcoplasmic reticulum, and triads from mammalian fast-twitch skeletal muscle.
Measured energized calcium transport, calcium pump ATPase activity, rapid calcium efflux, and ryanodine binding under varying conditions including ruthenium red and high magnesium ion concentrations.
Junctional terminal cisternae showed low net energized calcium transport relative to light and heavy sarcoplasmic reticulum, driven by high intrinsic calcium permeability.
Ruthenium red or elevated magnesium inhibited rapid calcium efflux and restored calcium transport and pumping efficiency in junctional terminal cisternae to levels observed in light sarcoplasmic reticulum.
Ryanodine blocked the ruthenium red-induced enhancement of calcium loading, with ryanodine binding sites measuring two orders of magnitude lower in abundance than calcium pump proteins.

Structured PICO

Population

Mammalian fast skeletal muscle sarcoplasmic reticulum fractions (junctional terminal cisternae, light and heavy sarcoplasmic reticulum, isolated triads)

Exposure

Ruthenium red, high [Mg2+], or ryanodine

Comparator

Untreated fractions or comparison between different sarcoplasmic reticulum fractions

Outcome

Ca2+ fluxes, Ca2+ transport, and Ca2+ pumping efficiencysurrogate

The study demonstrates that junctional terminal cisternae of fast skeletal muscle sarcoplasmic reticulum contain the predominant localization of Ca2+ release channels, explaining their high Ca2+ permeability and low net Ca2+ transport.

Cite This Study

Chu et al. (1986) studied this question. Junctional terminal cisternae vs. Light and heavy sarcoplasmic reticulum and isolated triads was evaluated on Ca2+ fluxes and transport. Junctional terminal cisternae exhibit decreased Ca2+ transport due to enhanced permeability to Ca2+, reflecting the predominant localization of Ca2+ release channels.

synapsesocial.com/papers/6aa3de3834a74eb94ec7fc90 https://doi.org/10.1021/bi00373a028

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Functional characterization of junctional terminal cisternae from mammalian fast skeletal muscle sarcoplasmic reticulum

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Functional characterization of junctional terminal cisternae from mammalian fast skeletal muscle sarcoplasmic reticulum

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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