Abstract
Whole-cell and single-channel Ca2+ currents (ICa) of single fetal (12 – 18 days) and neonatal (1 – 10 d) rat ventricular myocytes were recorded using patch clamp techniques. Whole-cell ICa density increased markedly during the fetal period and remained almost constant during the neonatal period. In cell-attached patch recordings (with 110 mM Ba2+ in the pipette), the L-type Ca2+ channels, observed on both fetal d-12 and neonatal d 5, had the same conductance (23 pS). On fetal d-12, many relatively long openings were observed in addition to brief openings, whereas on neonatal d-5, long openings were less observed and brief openings dominated. Therefore, long openings of the Ca2+ channels occur in early development in rat heart cells, similar to that reported for chick hearts [7, 8]. The increase of the whole-cell current amplitude observed during development may be due to an increase in available channel number.
References
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Masuda, H., Sumii, K. & Sperelakis, N. Long openings of calcium channels in fetal rat ventricular cardiomyocytes. Pflügers Arch. 429, 595–597 (1995). https://doi.org/10.1007/BF00704167
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DOI: https://doi.org/10.1007/BF00704167