Effect of anticonvulsants on the uptake of 5-methyltetrahydrofolic acid by the choroid plexus in rabbits.
1. The isolated choroid plexus of the rabbit takes up 5-methyltetrahydrofolate from the incubation medium. 2. Other folate analogues (pteroylglutamic acid, methotrexate, 5-formyltetrahydrofolate = folinic acid) inhibited the uptake of 5-methyltetrahydrofolate. 3. The uptake of 5-methyltetrahydrofolate was inhibited by low temperature, anaerobic conditions and dinitrophenol. 4. The anticonvulsant drugs, diphenylhydantoin and phenobarbital, had no effect on 5-methyltetrahydrofolate uptake. 5. The inhibitory effect of pteroylglutamic acid on the uptake of 5-methyltetrahydrofolate by the choroid plexus may explain the effect of long-term folic acid therapy in aggravating vitamin B12 neuropathy in pernicious anaemia.
D000818:Animals; D002831:Choroid Plexus / Q000187:drug effects / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D066298:In Vitro Techniques; D010634:Phenobarbital / Q000494:pharmacology*; D010672:Phenytoin / Q000494:pharmacology*; D011817:Rabbits; D013696:Temperature; D013763:Tetrahydrofolates / Q000378:metabolism*
D004140:Dinitrophenols; D013763:Tetrahydrofolates; D010672:Phenytoin; D010634:Phenobarbital