ANGPT1 and Cerebral ischemia: Because endogenous Ang1 expression was observed in neuronal cells in addition to cerebral blood vessels (Figure 1Am–p), immunohistochemical staining was used to quantify endogenous Ang1-positive vessel density 24 h after focal cerebral ischemia with the goal of evaluating endogenous Ang1 expression in cerebral blood vessels (Figure 3A).