Key result
Myocyte maturation shifts half-maximal Ca2+ current inactivation by ~13 mV toward a less negative potential.
Why the study?
Measurement of voltage-gated Ca2+ current in immature rabbit cardiac myocytes showed unexpectedly low Ca2+ channel activity, motivating characterization of ICa kinetics across developmental stages.
Population
Acutely isolated 21-day fetal (n=5), 1-5-day-old neonatal (n=5), and adult (n=6) rabbit cardiac myocytes
Comparison
ICa kinetic properties compared across fetal, neonatal, and adult myocytes
Design
Whole-cell voltage-clamp technique study
Authors
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Maturation shifts Ca2+ channel inactivation in rabbit myocytes; leaves open translation to human developmental electrophysiology and pediatric arrhythmia mechanisms.
p-value: p=<0.005
Immature rabbit cardiac myocytes exhibit kinetic properties of Ca2+ channels that place them at a relative disadvantage for total Ca2+ influx during depolarization compared to adult cells.
Wetzel et al. (1993) studied Rabbit cardiac myocytes (n=16). Developmental stage (maturation) vs. Adult cardiac myocytes was evaluated on Membrane potential for half-maximal steady-state inactivation (p=<0.005). The membrane potential for half-maximal steady-state inactivation of Ca2+ current became less negative with maturation (-24 mV in fetal, -19 mV in neonatal, and -11 mV in adult myocytes; p<0.005).
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