Figure 2.

Dose and time-dependent S1P-induced retraction of adult DRG neurons in vitro. (A) Representative example of wt adult sensory neurons at 0, 30 and 60 min after S1P and the retractive effect on already existing neurites. Scale bar = 30 μm. (B) Growth cones of adult wt DRG neurons retracted within 15 min upon 1 μM S1P treatment. The distance covered by retracting growth cones was significantly higher at 90 min compared to 15 min (p = 0.0014, one-way ANOVA followed by Tukey post hoc test; n = 41). (C) S1P elicited a retractive effect in a dose-dependent manner, with nearly 80% of cells retracting and the number of elongating neurons decreasing after 1 μM S1P (p = 0.0001, χ²-test; vehicle n = 35, S1P 10 nM n = 65; 100 nM n = 65; 1 μM n = 30). (D) Representative example at higher magnification of growth cone collapse after S1P treatment. Scale bar 10 μm. *p < 0.05, **p < 0.01, ***p < 0.001.