Calcium-dependent alterations in dendritic architecture of hippocampal pyramidal neurons

DENDRITIC arbor formation and the underlying mechanisms are crucial for the functional connectivity and plasticity of neurons. We used a focal electri c field to locally raise calcium levels in individual dendritic shafts of i solated hippocampal pyramidal neurons, in order to develop an accessible sy stem for studying dendritic branch formation, and to test the role of calci um as an intrinsic signal that may participate in arborization. Filopodia w ere induced in a manner temporally and spatially related to induced calcium rises. Certain filopodia also thickened and were transformed into dendriti c branches. These results suggest that calcium-mediated signaling can induc e branching in dendrites, and describe an accessible system for studying th e intracellular machinery that drives dendritic arborization. (C) 1949 Lipp incott Williams & Wilkins.