STEREOSPECIFIC OCCURRENCE OF A PARKINSONISM-INDUCING CATECHOL ISOQUINOLINE, N-METHYL(R)SALSOLINOL, IN THE HUMAN INTRAVENTRICULAR FLUID

N-Methyl(R)salsolinol, an endogenous neurotoxin, has been proposed to be closely involved in the pathogenesis of Parkinson's disease. The se lective toxicity to dopaminergic neurons was strictly limited for (R)e nantiomer of N-methylsalsolinol. Its precursor, (R)salsolinol was enzy matically synthesized from dopamine and acetaldehyde in human. However , it has never been examined whether a non-enzymatic reaction produces racemic salsolinol derivatives from dopamine especially in patients u nder L-DOPA therapy. To clarify the point, their contents were examine d in intraventricular fluid from parkinsonian patients administrated w ith L-DOPA. Only (R)enantiomer of N-methylsalsolinol and very low conc entration of salsolinol could be detected. The results suggest that N- methyl(R)salsolinol synthesis may not depend on dopamine level, but on the activity of enzymes related to its synthesis and/or catabolism. T he results are discussed in relation to pathogenesis Parkinson's disea se.