Figure 7.

Blocking of IGF-I receptor with αIR-3 did not block NGF-induced differentiation of trkA-transfected SY5Y cells, but resulted in a decreased [³H]dthymidine uptake. A: Cells were cultured in RPMI with 10% FBS in the absence of tetracycline and the presence of NTs (100 ng/ml) for 4 days. The fractions of the cells showing neurite extension, which was defined as an elongation of the cell process to more than two times the cell body diameter, were determined for at least 200 cells. Addition of αIR-3 at a concentration of 2 μg/ml did not counteract NGF-induced differentiation of the trkA-transfected cells. B: Treatment of TA25 and TA88 with αIR-3 at different concentrations (0, 0.5, 1, 2 μg/ml) resulted in a decreased [³H]dthymidine uptake. The cells were grown in RPMI with 10% FBS and were treated with 100 ng/ml of NGF in the absence of tetracycline. Radioactivity was measured on day 4 after 20 hours of incubation with 1 μCi of [³H]dthymidine. *Differs from control at P < 0.05.