EXPRESSION AND POLARIZATION OF VGF IN DEVELOPING HIPPOCAMPAL-NEURONS

VGF is an NGF-inducible protein whose expression closely correlates wi th PC12 cell neurite outgrowth. Immunolocalization of VGF in PC12 cell s by electron microscopy revealed labeling of a subpopulation of large dense core vesicles. To determine whether VGF expression may be invol ved in neural and axonal differentiation, we examined VGF immunoreacti vity in developing cultured hippocampal neurons. Most VGF appeared to be in vesicles which were present in neurons from the earliest develop mental stages and were particularly abundant in a small number of neur ons, most of which were GABAergic. VGF became restricted to axons afte r dendrites had begun to mature, a stage more closely associated with synaptogenesis than axonal polarization. Colocalization studies sugges t that VGF-containing and synaptophysin-containing vesicles are distin ct and differentially distributed.