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Taurine Biosynthesis in Rat Brain In Vivo: Lack of Relationship with Cysteine Sulfinate Decarboxylase Glutamate Decarboxylase‐Associated Activity (GAD/CSDII)
Author(s) -
Legay Frangois,
Lecestre Dominique,
Tappaz Marcel
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb04099.x
Subject(s) - taurine , glutamate decarboxylase , substantia nigra , in vivo , carboxy lyases , biochemistry , glutamate receptor , chemistry , endocrinology , cysteine , enzyme , medicine , biology , amino acid , dopamine , dopaminergic , receptor , microbiology and biotechnology
Abstract: Two distinct forms of cysteine sulfinate decarboxylase (CSD), respectively, CSDI and CSDII, have already been separated in rat brain. One of them, CSDII, appeared to be closely associated wtih glutamate decarboxylase (GAD). We have investigated whether the taurine concentration in brain was dependent on CSDII activity in vivo. CSDI and CSDII activities were specifically measured in crude brain extracts after selective immunotrapping. After 4 days of chronic treatment of mice with γ‐acetylenic γ‐aminobutyric acid, a drastic and identical decrease in CSDII and GAD activities was observed in the brain. Taurine concentration and CSDI activities were not significantly altered. Following striato‐nigral pathway lesioning in the rat brain, GAD and CSDII show an identical 80% decrease in the substantia nigra. In contrast, CSDI activity and taurine concentration in the substantia nigra were similarly but only slightly affected with an about 30% decrease. Our results provide further evidence that GAD and CSDII are indeed the same enzyme. They show that CSDII does not play any role in the biosynthesis of taurine in vivo. Our findings suggest that CSDI might be the biosynthetic enzyme for taurine in vivo and that there might be some endings projecting into the substantia nigra that contain CSDI and taurine.