Figure 7

Fig. 7. Effect of Brefeldin A treatment on axonal growth. (A) DIC images of a neurite growing on Con A coated substrate. Numbers indicate time in minutes. Brefeldin A (10 µg/ml) was applied 16 min after the start of experiment. Elongation of the neurite after BFA application visibly slowed down and the growth cone retracted within 12 min after drug treatment (28 min after the start of experiment). Bar, 10 µm. (B-C) Neurite growth on laminin-coated substrate after Brefeldin A treatment. (B) Phase contrast images of a neurite. Numbers indicate time in minutes after Brefeldin A (10 µg/ml) application. Axonal growth continues for at least 3 hours after drug treatment. (C) Quantitative analysis of axonal elongation. Data from experiment (B). The growth cone position relative to the substrate is plotted in 20 min intervals. The average direction of axonal growth is indicated by an arrow. The growth cone elongation appears to slow down within 80 min after application of BFA. About 5 hours after drug application the growth cone retracts (arrowhead). However, elongation resumed and continued for about 80 min after which the neurite retracted. Bars, 40 µm.