CENTRAL ADMINISTRATION OF VITAMIN-B-12 AGGRAVATES CATAPLEXY IN CANINENARCOLEPSY

EXPERIMENTAL evidence in canine narcolepsy suggests that central choli nergic systems are critically involved in the regulation of cataplexy, an abnormal manifestation of REM sleep atonia. In the current study, we found that intracerebroventricular perfusion of methyl-B-12, (10(-5 )-10(-2)M), significantly aggravated cataplexy and enhanced REM sleep in narcoleptic dogs. Choline, a direct precursor of acetylcholine, was also found to aggravate cataplexy, while cyano-B-12, a vitamin B-12 a nalog without methyl donating abilities, had no effect on cataplexy. S ince both methyl-B-12 and choline are reported to enhance acetylcholin e synthesis, enhancement of the biosynthesis of acetylcholine may be i nvolved in the effects observed in canine narcolepsy. Our results sugg est that central administration of methyl-B-12 has the potential to mo dulate both normal and pathological REM sleep.