Long openings of calcium channels in fetal rat ventricular cardiomyocytes.
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.
Masuda
H
H
Department of Pediatrics, Hiroshima University School of Medicine, Japan.
Sumii
K
K
Sperelakis
N
N
D000367:Age Factors; D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D018408:Patch-Clamp Techniques; D051381:Rats; D013997:Time Factors
D015220:Calcium Channels