Figure 4.

A combination of a somatic calcium rise and membrane depolarization induces axonal calcium sweep and axon retraction. A, Local application of ionomycin (10 μm in pipette) to the perisoma induced a calcium increase in the soma, but not the axonal calcium sweep (left), nor did it induce axon retraction (right) (n = 6). B, Local application of ionomycin to the axon terminal induced a calcium increase in the axon tip, which did not lead to axon retraction (n = 5). C, Depolarization induced by current injection with the patch-clamp technique did not induce either axonal calcium sweep or axon retraction (n = 4). D, A combination of perisomatic ionomycin and current injection induced axonal calcium sweep and axon retraction. *p < 0.05 versus 0 min, paired t test (n = 6). E, Bath application of 10 μm NASPM inhibited both axonal calcium sweep and axon retraction induced by perisomatic glutamate application (n = 6). Error bars indicate SEM.