Asymmetric dimethylarginine in psychiatric disorders

Asymmetric dimethylarginine (ADMA) is a derivative of the amino acid arginine that circulates in human plasma. As it is an inhibitor of nitric oxide synthase (NOS), it might have an influence on the pathophysiology of various disorders associated with low concentrations of nitric oxide, such as endothelial dysfunction and coronary heart disease, but also psychiatric disorders.

Various reports in the literature indicate that the plasma concentration of ADMA is increased in patients with schizophrenia or depression compared to healthy ones. Therefore, an association between ADMA and these diseases is suggested.

The concentration of ADMA in plasma is measured by HPLC with fluorescence detection. Since ADMA itself does not fluoresce, a derivatization step with o-phthaldialdehyde and 3-mercaptopropionic acid is necessary. This creates an adduct that can be quantified using a fluorescence detector.

The elevated plasma ADMA concentration may provide new starting points for diagnosis and treatment of these diseases. The routine quantification of ADMA may also become an important tool for therapy monitoring of psychiatric disorders.