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Effects of tetrahydroisoquinolines on dopa decarboxylase and pyridoxal kinase
Author(s) -
Ebadi Manuchair,
Govitrapong Piyarat
Publication year - 1981
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/ddr.430010205
Subject(s) - pyridoxine , levodopa , pyridoxal , chemistry , aromatic l amino acid decarboxylase , pharmacology , pyridoxal phosphate , decarboxylase inhibitor , biochemistry , tetrahydroisoquinoline , in vivo , enzyme , medicine , stereochemistry , biology , cofactor , parkinson's disease , microbiology and biotechnology , disease
The mechanism of the nullification of the therapeutic effects of levodopa by pyridoxine in parkinsonian patients is not known and is still a subject of much speculation. Among other suggestions, it has been proposed that pyridoxine and levodopa may form tetrahydroisoquinoline derivatives in vivo, which may in turn inhibit dopa decarboxylase or act as a false transmitter. This possibility was tested by synthesizing six tetrahydroisoquinoline derivatives and by studying their effects on dopa decarboxylase in brain homogenates. These compounds in concentrations of 50 mM did not inhibit dopa decarboxylase or pyridoxal kinase, which synthesizes pyridoxal phosphate.