S1PR1 and ischemic stroke: Activation of sphingosine-1-phosphate receptor-1 by FTY720, a known sphingosine 1-phosphate receptor agonist, is neuroprotective after ischemic stroke in rats (Rosen et al., 2007; Hasegawa et al., 2010; Pfeilschifter et al., 2010; Maceyka and Spiegel, 2014; Prager et al., 2015; Sun et al., 2016).