THALIDOMIDE, A HYPNOTIC WITH IMMUNE MODULATING PROPERTIES, INCREASES CATAPLEXY IN CANINE NARCOLEPSY

Thalidomide is a sedative hypnotic that was widely used in the 1950s b ut was withdrawn due to its teratogenic properties. The compound has r ecently been reintroduced as an immune modulating agent. Thalidomide s ignificantly aggravates canine cataplexy, a pathological manifestation of rapid eye movement (REM) sleep atonia seen in narcolepsy. This com pound also increases REM sleep and slow wave sleep in these animals. I n vitro receptor binding and enzyme assays demonstrate that thalidomid e does not bind to or enzymatically modulate the neurotransmitter syst ems reported to be involved in the regulation of cataplexy. Thalidomid e may therefore affect cataplexy through its immune modulation propert ies. Further studies on the mechanisms of action of thalidomide should increase our understanding of the pathophysiology of this disabling d isorder.