Table 5.

The role of Ca²⁺ in the axonal response to NGF-coated beads

Treatment	Protocol	% Filopodial responses (n)
Saline	1	73  (159)
Ca2+-free saline
+1 mmEGTA	1	83  (184)
+1 μm TH	1	81  (133)*
+10 μm RY	1	82  (146)*
+5 μmIO	1	76  (128)**
+1 μm TH and 10 μm RY	1	79  (167)**
+1 μm TH and 5 μm IO	2	63  (173)**
+5 μm IO and 10 μm RY	1	75  (181)**
+1:500 DMSO	1	71  (191)
+1:500 DMSO	2	62  (184)

Protocol 1: The culture medium was changed to either saline or Ca²⁺-free saline containing drugs 2 hr before the introduction of beads, and cells were fixed 3 hr later. Protocol 2: The culture medium was changed to Ca²⁺-free saline 2 hr before bead addition; thapsigargin (TH) and ionomycin (IO) were added 20 min before the beads. Cells were fixed 1 hr later. The Fischer’s exact test (one-tailed) was used to compare experimental results from experiments using drugs with the DMSO controls within experimental protocol, and the two-tailed test was used to compare the saline versus the Ca²⁺-free + EGTA saline results (p, 0.025). RY, Ryanodine. n refers to the number of bead–axon interactions scored.

*p < 0.05; **p > 0.05.