Considering evidence that NOX2-derived O2− can facilitate mitochondrial Ca2+ uptake, as well as mtROS generation in the vasculature [24,76,77], a goal of future studies will be to examine the role of NOX2 in determining mitochondrial Ca2+ load, mtROS generation, and the significance of this mechanism to enhanced vasoconstrictor reactivity after CH exposure. This evidence concerns the gene CYBB and cyclic hematopoiesis.