NGB and Cerebral ischemia: In the presence of reduced tissue oxygenation and acidosis that occur in cerebral ischemia, NO is produced locally and released directly from heme groups, along with a reduction in oxygen, S-nitroso-albumin, and/or from nitrite by the activity of nitrite reductases including potentially deoxyhaemoglobin and xanthine oxidoreductase [58, 62].