Agmatine

Nitric oxide (NO) synthesis modulation. Both differential inhibition and activation of NO synthase (NOS) isoforms is reported.
Polyamine metabolism. Precursor for polyamine synthesis, competitive inhibitor of polyamine transport, inducer of spermidine/spermine acetyltransferase (SSAT), and inducer of antizyme.
Protein ADP-ribosylation. Inhibition of protein arginine ADP-ribosylation.
Matrix metalloproteases (MMPs). Indirect down-regulation of the enzymes MMP 2 and 9.
Advanced glycation end product (AGE) formation. Direct blockade of AGEs formation.
NADPH oxidase. Activation of the enzyme leading to H2O2 production.
Oral agmatine is absorbed from the gastrointestinal tract and readily distributed throughout the body.
Rapid elimination from non-brain organs of ingested (un-metabolized) agmatine by the kidneys has indicated a blood half life of about 2 hours.
It is synthesized in the brain.
Binds to α2-adrenergic receptor
Binds to imidazoline receptor binding sites
Blocks NMDA receptors
Blocks other cation ligand-gated channels
Systemic agmatine can potentiate opioid analgesia
Systemic agmatine can prevent tolerance to chronic morphine in laboratory rodents
Cumulative evidence amply shows that agmatine inhibits opioid dependence and relapse in several animal species