NOS1 and major depressive disorder: In support of this, inhibition of NOS by the administration of N-omega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), an inhibitor of both nNOS and eNOS [85], and the administration of aminoguanidine (20 μg/μL, iNOS inhibitor) can prevent the development of behavior associated with depression in chronically stressed rats [86].