Table 1.

Dynamic microtubule ends are required for growth cone turning induced by diffusible molecules

Chemicals in pipetteChemicals in bathPipette distance (μm)Culture typesTurning angle (degree)*Extension (μm)*Turning scores (%)1-aNumber of cells examined
+0
NoneNone100 6 hr1.3  ± 3.613.5  ± 1.130452520
50 μmglutamateNone100 6 hr9.4  ± 2.91-16017.4  ± 1.361211833
50 μm glutamate10 nmnocodazole100 6 hr2.5  ± 1.415.3  ± 1.918463633
50 μm glutamate7 nm taxol100 6 hr−4.2  ± 3.110.4  ± 0.81-16025403520
5 μg/ml netrin-11-bNone100 6 hr−10.1  ± 2.01-16015.1  ± 1.65207520
5 μg/ml netrin-11-b10 nmnocodazole100 6 hr0.7  ± 3.213.8  ± 1.130403023
5 μg/ml netrin-11-b4 nmvinblastine100 6 hr0.2  ± 2.610.0  ± 1.11-16030452520
5 μg/ml netrin-11-b7 nmtaxol100 6 hr0.5  ± 3.612.1  ± 2.039332818
NoneNone10018 hr−0.2  ± 3.322.9  ± 2.130403020
5 μg/ml netrin-1None10018 hr9.3  ± 3.41-16019.2  ± 1.568161619
5 μg/ml netrin-110 nm nocodazole10018 hr−2.7  ± 2.920.2  ± 1.821374219
5 μg/ml netrin-14 nm vinblastine10018 hr1.2  ± 3.610.2  ± 1.21-16028393318
5 μg/ml netrin-17 nm taxol10018 hr1.1  ± 3.213.5  ± 1.71-16039303123
  • * Values represent mean ± SEM.

  • F1-160 Significantly different from the control groups (p < 0.05; Kolmogorov–Smirnov test).

  • F1-a Growth cone turning responses were scored as follows: +, growth cones showing positive turning toward the pipette (turning angle ≥5°); 0, growth cones showing no turning (turning angle <5°); −, growth cones turning away (turning angle ≤−5°).

  • F1-b Growth cone repulsion induced by netrin-1 gradients was performed on neurons in 6 hr cultures without NT-3 supplemented in the culture medium.