3,4-Dihydroxyphenylacetaldehyde
3,4-Dihydroxyphenylacetaldehyde, also known as dopamine aldehyde, is a metabolite of the monoamine neurotransmitter dopamine formed by monoamine oxidase.
Other metabolic pathways of dopamine metabolism include methylation by catechol O-methyltransferase into 3-methoxytyramine and β-hydroxylation by dopamine β-hydroxylase into norepinephrine. There is also spontaneous oxidation of dopamine into dopamine quinones and reactive oxygen species.
Dopaminergic neurotoxicity
DOPAL is known to be a dopaminergic neurotoxin. It is much more potent in this regard than dopamine itself and other metabolites of dopamine. According to the catecholaldehyde hypothesis, DOPAL plays a role in aging-related dopaminergic neurodegeneration and in the pathogenesis of Parkinson's disease. DOPAL is detoxified mainly by aldehyde dehydrogenase. DOPAL is a metabolite of dopamine formed by monoamine oxidase. In differentiated neuronal cells of the PC12 [cell line|PC12 line], physiological concentrations of DOPAL in isolated mitochondria were highly potent in inducing a pathway associated with programmed cell death, permeability transition. This suggests the cytotoxity of DOPAL and its role in the progression of Parkinson's disease, which has long been associated with mitochondrial abnormalities and neurotoxicity by way of dopaminergic compounds, while reducing the emphasis on other dopamine derivatives and metabolites.Aldehyde dehydrogenase inhibitors, which prevent the catabolism of DOPAL and thereby increase DOPAL levels, can produce dopaminergic neurotoxicity or augment dopaminergic neurodegeneration. Examples of ALDH inhibitors include disulfiram and other known dopaminergic neurotoxins including benomyl, daidzin, dieldrin, methylmercury, rotenone, and ziram. DOPAL itself is also known to inhibit ALDH at high concentrations.