August 1, 1993AJP Cell Physiology
Twitch-dependent SR Ca accumulation and release in rabbit ventricular myocytes
Key result
After SR Ca depletion in rabbit ventricular myocytes, four to five twitches are necessary to reload the SR to the steady-state level, and 90 s of 5 microM TG completely prevents SR Ca reuptake.
Population
Rabbit ventricular myocytes
Design
Preclinical
Authors
Discussion
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Implication
Rabbit myocyte findings warrant caution against clinical translation; leaves open human SR Ca dynamics in depleted states.
Structured PICO
P
Population
Rabbit ventricular myocytes
I
Intervention
Caffeine-induced contractures (10 mM) and thapsigargin (5 microM)
O
Outcome
Fraction of sarcoplasmic reticulum (SR) Ca released at one twitch and number of twitches required to reload a Ca-depleted SRsurrogate
In rabbit ventricular myocytes, 4-5 twitches are required to reload a Ca-depleted sarcoplasmic reticulum, and SR Ca-ATPase activity limits the ability of calcium influx to activate contraction when the SR is depleted.
Cite This Study
Bassani et al. (1993) studied this question. Caffeine and thapsigargin was evaluated on Sarcoplasmic reticulum (SR) Ca accumulation and release. After SR Ca depletion in rabbit ventricular myocytes, four to five twitches are necessary to reload the SR to the steady-state level, and 90 s of 5 microM TG completely prevents SR Ca reuptake.