''N''-Methylarginine is an
inhibitor of
nitric oxide synthase
Nitric oxide synthases () (NOSs) are a family of enzymes catalyzing the production of nitric oxide (NO) from L-arginine. NO is an important cellular signaling molecule. It helps modulate vascular tone, insulin secretion, airway tone, and p ...
.
Chemically, it is a
methyl derivative of the
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
arginine. It is used as a biochemical tool in the study of physiological role of
nitric oxide.
The inhibiting effect of ''N''-methylarginine on
vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstrictio ...
is lower in
hypertensive patients than in normal subjects, indicating
endothelial dysfunction
In vascular diseases, endothelial dysfunction is a systemic pathological state of the endothelium. Along with acting as a semi-permeable membrane, the endothelium is responsible for maintaining vascular tone and regulating oxidative stress by ...
.
The inhibiting effect of ''N''-methylarginine on vasodilation declines progressively with age, but has been restored with
vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) ...
in the oldest subjects.
An example of N-methylarginine soluble form, that has been used in a number of clinical research trials can be found here.
See also
*
Asymmetric dimethylarginine
References
{{reflist
Amino acids
Guanidines