Developmental changes in membrane Ca2+ and K+ currents in fetal, neonatal, and adult rabbit ventricular myocytes

T. V. Huynh, F. Chen, G. T. Wetzel, W. F. Friedman, T. S. Klitzner

Research output: Contribution to journalArticlepeer-review


Whole-cell calcium current (I(Ca)) and inwardly rectifying potassium current (I(K1)) were studied in 21-day fetal, 28-day fetal (total gestation, 31 days), 2-5-day neonatal, and adult rabbit ventricular myocytes isolated by enzymatic dissociation. Whole-cell peak I(Ca) and I(K1) at -100 mV increased significantly after birth. Cell size approximated from cell membrane capacitance also increased with age, with the most significant increase occurring after birth. When normalized to cell surface area, peak I(Ca) density increased from day 21 of gestation to the neonate and then increased again from neonate to adult. In all age groups, peak I(Ca) occurred at a test potential of +10 mV, and the shape of the Ca2+ current-voltage relation did not change with age. These findings suggest that there are no significant developmental changes in the voltage dependence of I(Ca). Therefore, the measured age-related increase in Ca2+ current density may result from increased channel expression. I(K1) also exhibited a pattern of increasing current density with age. For I(K1), the increase in current density was most rapid between day 21 and the perinatal period and much slower after birth. These results demonstrate that I(Ca) and I(K1) undergo significant changes during late fetal and postnatal development.

Original languageEnglish (US)
Pages (from-to)508-515
Number of pages8
JournalCirculation research
Issue number3
StatePublished - 1992
Externally publishedYes


  • calcium
  • immature myocardium
  • ion flux
  • ionic currents
  • potassium

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine


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