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L-m-Tyrosine and Parkinsonism

George C. Cotzias, MD; Paul S. Papavasiliou, MD; Ismael Mena, MD
JAMA. 1973;223(1):83. doi:10.1001/jama.1973.03220010069038.
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To the Editor.—  Administrations of levodopa, which generates the primary catecholamine dopamine, or of the tertiary catecholamine apomorphine hydrochloride, have improved the symptoms of parkinsonism.1,2 L-m-tyrosine generates the primary amine m-tyramine, which does not have a catechol configuration, not even an equivalent one. In experimental animals, however, L-m-tyrosine had induced manifestations similar to those induced by levodopa, which differed somewhat from those of apomorphine.3,4 L-m-tyrosine was, therefore, proposed for the treatment of parkinsonism.These considerations produced two reasons for testing the effects of L-m-tyrosine on the symptoms of parkinsonism: (1) to determine whether or not the catechol moiety is necessary for the therapeutic actions of amines in this disease, and (2) to determine whether or not reactions of animals to a new drug can be extrapolated into therapy on the basis of their being similar to those of an


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