What is the clinical evidence from this study?

Study design: Other. Intervention: Rubidium ions (Rb+) vs. Potassium ions (K+). Primary outcome: Unitary currents and channel gating properties.

What question did this study set out to answer?

To investigate how replacing potassium ions with rubidium ions alters single-channel permeation and gating kinetics in delayed rectifier potassium channels of skeletal muscle.

April 1, 1989The Journal of PhysiologyOpen Access

Rubidium ions and the gating of delayed rectifier potassium channels of frog skeletal muscle.

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Key result

Rubidium ions prolonged the duration of delayed rectifier potassium channel opening in frog skeletal muscle, with mean open time being 2.65 times greater compared to potassium ions.

Population

Frog skeletal muscle delayed rectifier potassium channels

Comparison

Rubidium ions (Rb+) as charge carrier vs Potassium ions (K+) as charge carrier

Design

Preclinical

Authors

ASAusten SpruceUniversity of Birmingham NSN. B. StandenLa Trobe University PSPeter StanfieldGoogle (United States)

Discussion

Member takes

Implication

Hypothesis-generating for delayed rectifier gating; leaves open relevance to mammalian cardiac electrophysiology.

Key Points

To investigate how replacing potassium ions with rubidium ions alters single-channel permeation and gating kinetics in delayed rectifier potassium channels of skeletal muscle.
Measured unitary currents and ensemble-averaged currents through delayed rectifier potassium channels in frog skeletal muscle using potassium or rubidium as the current carrier.
Calculated permeability ratios (PRb/PK) by tracking changes in reversal potential upon ionic substitution at the channel's internal and external mouths.
Analyzed open-time distributions, burst durations, and tail currents following membrane depolarization and repolarization.
Unitary currents exhibited reduced amplitude in Rb+, yielding permeability ratios (PRb/PK) of 0.92 at the external mouth and 0.67 at the internal mouth.
Mean channel open time, fitted by a single exponential indicating a single open state, was 2.65 times greater across all tested voltages in Rb+ compared to K+.
Tail currents under repolarization were prolonged approximately tenfold in Rb+, driven by increases in the number of openings per burst and bursts per tail.

Structured PICO

Population

Frog skeletal muscle delayed rectifier potassium channels

Intervention

Rubidium ions (Rb+) as charge carrier

Comparator

Potassium ions (K+) as charge carrier

Outcome

Unitary currents, permeability ratios, and channel gating kinetics (activation, tail currents, open times)surrogate

Rubidium ions permeate delayed rectifier potassium channels less readily than potassium but significantly prolong channel open times and tail currents, providing insights into channel gating mechanisms.

Cite This Study

Spruce et al. (1989) studied this question. Rubidium ions (Rb+) vs. Potassium ions (K+) was evaluated on Unitary currents and channel gating properties. Rubidium ions prolonged the duration of delayed rectifier potassium channel opening in frog skeletal muscle, with mean open time being 2.65 times greater compared to potassium ions.

synapsesocial.com/papers/6ab323cd029344f15864988c https://doi.org/10.1113/jphysiol.1989.sp017593

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Rubidium ions and the gating of delayed rectifier potassium channels of frog skeletal muscle.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Rubidium ions and the gating of delayed rectifier potassium channels of frog skeletal muscle.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider