Fig. 5.
Top. Soluble LN induces an elevation of [Ca2+]i in surgically isolated filopodia. Using laser scissors, we surgically isolated individual filopodia from growth cones loaded previously with 5 μmfura-2AM for 35 min (phase picture, left panel). Fura images were acquired 30 min after surgical isolation, and only filopodia with stable resting [Ca2+]iwere considered for further experiments (middle panel). Damaged filopodia generally had [Ca2+]i levels >1 μm. Bath application of 20 μl of LN (20 μg/ml) stimulated an immediate rise of [Ca2+]i determined 2 min after LN application (right panel). The color bar shows linear Ca2+ concentrations. Scale bar, 10 μm.