Microscopy Research and Technique vol:48 issue:1 pages:3-11
Neurons begin to polarize when one of the neurites becomes the axon. Hippocampal neurons in cell culture have a sharp transition between their unpolarized and polarized stage revealed by the rapid growth of the future axon. Recent progress shows that both a cytoplasmic membrane flow and actin dynamics govern axon formation, and thereby initial neuronal polarization. We here review these mechanisms, evaluate their physiological role, and show similarities to the transient polarization of migrating fibroblasts. Finally, we present a model how actin dynamics and vectorial membrane flow may interact to achieve axon formation. (C) 2000 Wiley-Liss, Inc.