Table 1.

Average axonal transport data obtained by studying the dynamics of granules containing tPA/GFP in movies generated from 10 representative PC12 cells, as described in MATERIALS AND METHODS

Linear density of granules containing tPA/GFP	v (μm/s)	% Anterograde	% Reversal
∼0.1 fluorescent granules/μm	0.92 ± 0.16	93 ± 10	14 ± 10
∼1.0 fluorescent granules/μm	0.46 ± 0.23	63 ± 3	15 ± 7
∼3.0 fluorescent granules/μm	0.28 ± 0.12	44 ± 10	31 ± 15

The data show that average granule speed and average percent anterograde flux depend on the linear density of granules along neurites. Average granule speed and average percent anterograde flux both steadily decrease as the linear density of granules containing tPA/GFP rises from ∼0.1 fluorescent granules/μm to ∼3 fluorescent granules/μm.