One such study by Xu et al. utilized an endovascular puncture mouse SAH model to examine the effects of inhibiting VAP-1 (a protein expressed on the surface of endothelial cells, that is, important in the binding of leukocytes) and neutropenia on pial arterial dilation.98 Forty-eight hours after SAH induction, both VAP-1 antagonism and neutropenia preserved arterial response to vasodilator administration whereas the vehicles had a >80% drop in arteriolar diameter response. Here, AOC3 is linked to neutropenia.