Fig. 8. LY and Wm inhibit IGF-1 stimulation of membrane expansion at the growth cone. Representative fluorescence micrographs (recorded in the red channel) of the axonal growth cones of hippocampal neurons in culture are shown. Neurons were labeled with BODIPY-ceramide for 30 minutes at room temperature and then chased for 2.5-3 hours at 37°C. Growth cones were challenged with 10 nM IGF-1 in the absence (control) or the presence of the PI3K inhibitors Wm (1 µM) or LY (20 µM). Note the rapid dissipation of fluorescence upon challenge with IGF-1 versus the persistence of fluorescent puncta in the presence of the PI3K inhibitors. Bar, 3 µm.