[The effect of droxidopa on the monoamine metabolsim in the human brain].

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Maruyama W, Naoi M, Narabayashi H

[The effect of droxidopa on the monoamine metabolsim in the human brain].

Rinsho Shinkeigaku. 1994 Oct;34(10):985-90.

PubMed ID

7834959 [ View in PubMed

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Abstract

Droxidopa (L-threo-3,4-dihydroxyphenylserine) is an artificial amino acid, which is used to supplement noradrenaline (NA) in neurodegenerative disorders. Droxidopa is decarboxylated into NA by aromatic L-amino acid decarboxylase in the brain, but its effects on other monoamine neurotransmitters, such as dopamine (DA) and serotonin (5-HT) have not been systematically examined. The monoamine metabolism has been suggested to interact with each other in the brain, and by analysis of the cerebrospinal fluid, L-DOPA, a precursor amino acid used for supplement of DA, was found to inhibit serotonin synthesis in the brain. To examine the effects of droxidopa on the monoamine metabolism, the intraventricular fluid of the patients administered with droxidopa and L-DOPA was analyzed. The levels of monoamines, their precursor amino acids, and their metabolites were compared between the patients administered with L-DOPA. In the patients administered by droxidopa and L-DOPA, droxidopa was shown to increase the concentrations of monoamines (NA, DA and 5-HT), but the difference was not statistically significant by comparison with those treated by L-DOPA alone. The metbolites of DA and 5-HT by monoamine oxidase, 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) were also found to increase by droxidopa administration. On the other hand, the metabolites of NA and DA by catechol-O-methyltransferase (COMT), normetanephrine (NMN) and 3-methoxytyramine (3-MT), decreased in the patients treated with droxidopa and L-DOPA compared with the patients administered with L-DOPA alone and control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

DrugBank Data that Cites this Article

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Droxidopa	Aromatic-L-amino-acid decarboxylase	Protein	Humans	Unknown	Substrate	Details