Figure 4.

Effect of NGF on DRG cell responsiveness. DRG cells were cultured for 5 days in Ham's F14 medium with increasing concentration of NGF. Cells were washed and stimulated with 1 μM cicaprost, and [³H]-cyclic AMP production assayed as described in Methods. Basal [³H]-cyclic AMP production ([cAMP]/[total AXP]×1000) was 1.78±0.12, 1.81±0.23, 1.60±0.14 and 1.49±0.20 for 0, 50, 100 and 200 ng ml⁻¹ NGF, respectively, for 500 cells well⁻¹. Basal [³H]-cyclic AMP production ([cAMP]/[total AXP]×1000) was 1.41±0.25, 1.54±0.22, 1.66±0.31 and 1.77±0.35 for 0, 50, 100 and 200 ng ml⁻¹ NGF, respectively, for 15,000 cells well⁻¹. Data represent mean±s.e.mean of three experiments, each performed in triplicate.