Time-dependent response of membrane fluidity to sphingomyelin treatment.

Cells were treated with SM-LA (15 μM) or vehicle for the indicated incubation times. The cells were labeled with 1,6-diphenyl-1,3,5-hexatriene (DPH), and the fluorescence anisotropy of the probe was determined. The measurements were performed at 37°C for 2 min immediately after the addition of the fluorescent probes. Each value is the mean±SEM of three independent experiments. P<0.05, P<0.005 and P<0.001; SM-treated cells compared with control cells.