Comparison of Ito in young and adult human atrial myocytes: evidence for developmental changes

In an effort to understand the ionic basis for the developmental changes that have been reported to occur in the configuration of the human atria1 action potential, we characterized the transient outward current Ito) and the inward rectifier current in atria1 myocytes isolated from 20 young (ages 1 day-2.5 yr) and 8 adult (11-68 yr) human hearts using the whole cell patch-clamp technique.