Fig. 7.

Histogram showing the effect of glutamate and GABA addition on the intracellular distribution of TfR. In Tf-starved cells (−Tf) glutamate addition induces a clear increase in the percentage of axonal TfR-positive structures (p < 0.001) (**), whereas GABA addition does not significantly change the number of axonal labeled organelles. In cells grown in the constant presence of Tf (+Tf) a 2 hr incubation with GABA decreases the percentage of axonal TfR (p < 0.001) (*). Glutamate addition does not produce a further increase (**).