Postnatal development of action potential-induced dendritic calcium entry in neocortical layer II/III pyramidal cells

By whole-cell patch-clamp recording and calcium imaging with fura-2, we inv estigated postnatal development of intracellular calcium dynamics in apical dendrites of layer II/III pyramidal cells in the rat visual cortex. Dendri tic calcium increases, induced by single action potentials, occurred only s lightly on postnatal days 8-10 (P8-10), and then underwent a gradual enhanc ement during the second postnatal week to become 2-3-fold larger on P16-18 than on P8-10. The results suggest that the developmental growth of calcium dynamics may play a critical role for functional development of neocortica l neurons. (C) 1999 Elsevier Science B.V. All rights reserved.