CX3CR1 and ischemic stroke: Using a combination of immunohistofluorescence staining and electrophysiological recordings we also showed that P2X4 is upregulated in activated microglia isolated from the brains of transgenic CX3CR1+/GFP mice following induction of ischemic stroke, in line with previous findings showing an upregulation of P2X4 in ischemic conditions (Cavaliere et al., 2003; Li et al., 2011; Wixey, Reinebrant, Carty, & Buller, 2009).