We examined whether forearm blood flow responses to intra-arterial acetylcholine , and nitroprusside , were altered with aging , with and without co-infusion of an inhibitor of nitric oxide synthase ( N ( G ) - mono-methyl-L-arginine ) in three groups of human subjects ; a group with clinical atherosclerotic vascular disease ( n = 31 , 21 M ) , otherwise healthy elderly ( n = 17 , 13 M ) , and healthy young controls ( n = 15 , 8 M ) .
