Figure 2.

Effect of PLA₂ inhibition on Sema3A-induced growth cone collapse. Growth cones of DRG neurons in explant cultures (on laminin) were exposed by bath application to either vehicle (control), Sema3A, or 12(S)-HETE, with or without pyrrolidine present. A and B, phase contrast micrographs of growth cones before (left panel) or 15 min after (right panel) bath application of either control medium or Sema3A. C and D, growth cones pre-incubated (15 min) with 1μM pyrrolidine, before (left panel) and 15 min after (right panel) bath application of either Sema3A or 10⁻⁸M 12(S)-HETE. Scale bar 10μm. E, growth cone area changes (mean % change ± SEM) over 15min in the presence of PLA₂ inhibitors, without Sema3A challenge. These values are not significantly different from that for control incubation. F, quantitative analysis of growth cone collapse in the presence of various PLA₂ inhibitors. Results are expressed as mean % change in growth cone area ± SEM, measured at t=0 min and t=15 min after onset of challenge. The inhibitor and concentration used, the challenge, and the n values are indicated below each condition, as are the p values when contrasting individual measurements. Because the distribution of values was marginally normal, p values are shown for both parametric (ANOVA, FDR) and non-parametric (K-W, Dunn’s procedure) statistical analyses. The overall p value was <0.0001 for both analyses. Grey shading has been added to facilitate reading of the graph.