Influence of dopaminergic agonists/antagonists on fucose metabolism in the rat brain.
Valid indications of a key role for dopaminergic drugs in glycoprotein fucosylation in neuronal tissue in vitro led us to investigate whether the administration of dopaminergic agonists/antagonists influences fucose metabolism in the rat brain in vivo. Three test groups were set up. Group 1 was given L-DOPA (210 mg/l), Group 2 haloperidol (10.5 mg/l) in drinking water, Group 3 served as control. The rats were sacrificed after 8 weeks and enzyme activities in 5 different brain areas were determined concerning the enzymes of the anabolic fucose metabolism: fucokinase, fucose-1-phosphate pyrophosphorylase and fucosyltransferase 1 and 2. Only the specific activity of fucokinase was affected by haloperidol or L-DOPA administration. In the olfactory bulbus, thalamus and cortex, haloperidol decreased fucokinase activity by 21%, 37%, and 39%, respectively (p < 0.05 in each case). No changes were observed in the cerebellum and striatum. Surprisingly, fucokinase activity in the cortex was decreased by L-DOPA (31%, p < 0.05).


CONCLUSIONS
Cerebral fucokinase activity is influenced in vivo by dopaminergic drugs in well circumscribed brain areas. Other enzymes of the anabolic fucose metabolism showed no change in activity. It is, therefore, conceivable that these drugs, apart from known mechanisms, exert part of their pharmacological action via a modulation of fucose metabolism.
Institut für Molekularbiologie und Biochemie, Universitätsklinikum Steglitz Freie Universität Berlin, Germany.
B
B
Hocher
F
F
Abou-Rebyeh
C
C
Bauer
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology; D002531:Cerebellum / Q000187:drug effects / Q000201:enzymology; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology; D003342:Corpus Striatum / Q000187:drug effects / Q000201:enzymology; D004298:Dopamine / Q000494:pharmacology*; D005643:Fucose / Q000378:metabolism*; D005647:Fucosyltransferases / Q000378:metabolism; D006220:Haloperidol / Q000494:pharmacology*; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D009833:Olfactory Pathways / Q000187:drug effects / Q000201:enzymology; D010770:Phosphotransferases / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor); D051381:Rats; D017208:Rats, Wistar; D013788:Thalamus / Q000187:drug effects / Q000201:enzymology
D005643:Fucose; D007980:Levodopa; D005647:Fucosyltransferases; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C020153:fucokinase; D006220:Haloperidol; D004298:Dopamine