BDNF stimulated outgrowth is Ca2+ dependent and requires Ca2+ release from internal stores.

(A) Bath application of BDNF elicits a strong Ca2+ signal in zebrafish growth cones (pseudocolored according to scale on left, with blue  =  lower [Ca2+] and white  =  higher [Ca2+]), quantified in (B). Treatment with both (C) BAPTA-AM, a cytoplasmic Ca2+ buffer, and (D) thapsigargin, which depletes intracellular Ca2+ pools, abolish BDNF stimulated outgrowth. Scale bar, 5 µm. *, p<0.05; ns, not significant.