L-NAME hydrochloride

L-NAME Hydrochloride is an inhibitor of nitric oxide synthase (NOS) with IC50 value of 70 μM [1].

NOS is an important enzyme involved in production of NO. NO, the smallest signaling molecule known, controls servoregulatory functions such as neurotransmission or vascular tone, regulates gene transcription and mRNA translation, as well as produces post-translational modifications of proteins [2].

At concentrations of 10^-9 ~ 10^-3 M, L-NAME Hydrochloride inhibited NOS purified from rat brains in a dose dependent manner, with IC50 value of 70 μM [1]. In another study, L-NAME Hydrochloride at 0.1 ~ 100 mM caused concentration-dependent inhibition of the Ca²⁺-dependent endothelial NO synthase from porcine aortae. L-NAME Hydrochloride also caused an endothelium-dependent contraction and an inhibition of the endothelium-dependent relaxation induced by acetylcholine (ACh) in aortic rings [3].

In anaesthetized rats, L-NAME Hydrochloride (0.03 ~ 300 mg/kg, i.v.) induced a dose-dependent increase in mean systemic arterial blood pressure accompanied by bradycardia. L-NAME Hydrochloride (100 mg/kg, i.v.) significantly inhibited the hypotensive responses to ACh and bradykinin. The increase in blood pressure and bradycardia produced by L-NAME Hydrochloride could be reversed by L-arginine (30 ~ 100 mg/kg, i.v.) in a dose-dependent manner [3].

References:

[1]. Pfeiffer S, Leopold E, Schmidt K, et al. Inhibition of nitric oxide synthesis by NG-nitro-L-arginine methyl ester (L-NAME): requirement for bioactivation to the free acid, NG-nitro-L-arginine. British Journal of Pharmacology, 1996, 118(6): 1433-1440.

[2]. Förstermann U, Sessa W C. Nitric oxide synthases: regulation and function. European Heart Journal, 2012, 33(7): 829-837.

[3]. Rees D D, Palmer R M, Schulz R, et al. Characterization of three inhibitors of endothelial nitric oxide synthase in vitro and in vivo. British Journal of Pharmacology, 1990, 101(3): 746-752.