Figure 7.

Axon length and distance between the axotomy site and the soma affects the velocity and delay until onset of phosphatidylserine externalization. A, Short, wild-type axons had a significantly faster velocity of propagation of phosphatidylserine externalization after transection compared with longer axons, to short PB1-treated axons, and to short Wld^S axons. The effect of PB1 treatment and the Wld^S mutation versus wild-type were significantly less in longer axons. B, Short, wild-type axons had a longer delay until initiation of phosphatidylserine externalization compared with long wild-type axons. This pattern was also seen in Wld^S axons, but not PB1-treated axons. C, Wild-type axons with the axotomy site near the soma had a significantly faster velocity of phosphatidylserine externalization compared with where the axotomy site was distant from the soma. The velocity was also significantly slower for Wld^S axons transected near the soma compared with wild-type. When axotomy was distant from the soma, neither PB1 treatment nor the Wld^S mutation affected velocity compared with wild-type, untreated axons. D, Axotomy near the soma in wild-type axons resulted in a longer delay until initiation of phosphatidylserine externalization compared with distant transections. This pattern was also seen in Wld^S axons, but not PB1-treated axons. *p < 0.05; **p < 0.01; ***p < 0.001.