Although both nNOS and iNOS are known to be expressed in brain, it is reported that only nNOS is continuously activated and produces NO during the early stages of cerebral ischemia, whilst iNOS protein expression and catalytic activity is detectable at 12 hours after cerebral ischemia and produces an excessive amount of NO in the late stages of ischemia [46]–[48]. Here, NOS1 is linked to ischemia.