SIRT1 and nervous system disorder: SIRT1 (silent mating type information regulation 2 homolog), a known nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, is present ubiquitously in the brain [16,17], and several studies have demonstrated a protective role of SIRT1 in various neurological disorders [18,19,20] including SAH [21,22].