Repeated (daily) FTY720 administration sustains the inhibition of pERK1/2 response. pERK1/2 levels in response to FTY720 (F) (100 nM) for 15 min in astrocytes that were initially exposed to a single dose of FTY720 (F) or vehicle (v) with washout after 1 h (1 h), or without washout (1×) or repeated daily for 5 days (5×). pERK1/2 activation by FTY720 was observed in the 1-h and single without-washout conditions, but not in the repeated daily FTY720 condition. β-Actin was used as the loading control. Quantified band intensity relative to untreated control (n = 3).