Figure 3.
Rotary shadow EM of untreated growth cones (A) and following bath application of Sema 3A (500 ng/ml for 30 min) (B). (A) Low magnifications reveal growth cones with varying morphologies similar to those observed by light microscopy. The amount of f-actin organized as bundles and meshworks varies depending on the degree of spreading. (B) Treatment with Sema 3A causes variable decreases in growth cone area from full to partial collapse. Most fully or partially collapsed growth cones lack lamellipodia or a distinct central domain containing actin meshworks. Bar=8 µm.