NOS3 and ischemia: Since post-ischemic upregulation of eNOS triggers cerebral angiogenesis accompanied by increased BBB permeability, ischemia/hypoxia-induced vascular plasticity might be regulated by the altering production of NO and H2S in different phases of ischemia and reperfusion in order to provide adequate proangiogenic microenvironment and to prevent dramatic alterations in the BBB structural integrity.