Our data suggest that (i) p-RIPK1 (Ser166) participated in RIPK3/MLKL-dependent neuronal necroptosis after cerebral ischemia; (ii) immunostaining with a specific antibody against p-RIPK1 (Ser166) could be used as a morphological biomarker for necroptosis. The gene discussed is RIPK1; the disease is brain ischemia.