B-50/GAP43 localization on membranes of putative transport vesicles in the cell body, neurites and growth cones of cultured hippocampal neurons.

We conducted an electron microscopic immunocytochemical study to locate B-50/GAP43 in various cellular elements of hippocampal neurons grown in dissociated cell culture. B-50 was detected with pre- and post-embedding immunoincubation, using affinity-purified B-50 antibodies and secondary antibodies coated on gold probes. For the first time ultrastructural evidence is presented for the location of B-50 on the membranes of electron-lucent transport vesicles with a diameter of 99.4 +/- 2.9 nm, present in the trans region of the Golgi apparatus, in neurites and in growth cones of cultured hippocampal neurons.