FORMATION OF FORMALDEHYDE FROM ADRENALINE IN-VIVO - A POTENTIAL RISK FACTOR FOR STRESS-RELATED ANGIOPATHY

Cardiovascular and cerebrovascular disorders are well known to be asso ciated with stress related behaviors, Stress enhances excretion of adr enaline, which is deaminated by monoamine oxidase and methylamine is f ormed. This product can be further deaminated by semicarbazide-sensiti ve amine oxidase (SSAO) and converted to toxic formaldehyde, hydrogen peroxide and ammonia. SSAO is located in the cardiovascular smooth mus cles and circulated in the blood. We investigated whether formaldehyde can be derived from adrenaline in vivo. Methylamine was confirmed to be a product of adrenaline catalyzed by type A monoamine oxidase (MAO- A). Irreversible and long-lasting radioactive residual activity was de tected in different tissues following administration of 1[N-methyl-H-3 ]-adrenaline. Such irreversible linkage could be blocked by selective MAO-A or SSAO inhibitors. Endothelial cells are quite sensitive to for maldehyde and relatively resistant to hydrogen peroxide. It is possibl e that stimulation of adrenaline excretion by chronic stress could inc rease the levels of circulatory formaldehyde. Such chronic ''formaldeh yde'' stress may be involved in the initiation of endothelial injury a nd subsequently angiopathy.