Fig. 6. Norepinephrine and synaptophysin levels in NT-treated SH-SY5Y/trkC and SH-SY5Y/trkA cells. A, norepinephrine was determined by high-performance liquid chromatography analysis in cells grown for 4 days in serum-containing medium ± 100 ng/ml of the indicated NT. Norepinephrine levels were adjusted for sample protein content and expressed as means (n = 45); bars, SE. B, distribution of synaptophysin in growth cones and cell bodies from NT-treated SH-SY5Y/trkC and SH-SY5Y/trkA cells, as determined by Western blot analysis. Cells were grown for 4 days in serum-containing medium supplemented with 100 ng/ml of NT-3 and NGF, respectively. Growth cones were prepared as described in "Materials and Methods," and 100 µg of protein from each of the cell body (CB) and growth cone (GC) preparations were separated by SDS-PAGE and blotted onto a nitrocellulose filter. The filter was incubated with an anti-synaptophysin antibody. Overexposure reveals a band (*) of the expected size for synaptophysin (Mr 42,000), also in the SH-SY5Y/trkC growth cone lane.