Propranolol in the treatment of narcolepsy

Serotoninergic systems are thought to be involved in production of slow-wave sleep and priming mechanisms that initiate REM sleep, whereas a dysfunction of both non-REM and REM sleep has been identified in narcolepsy with cataplexy. More recently, propranolol was shown to be an antagonist of serotonin's activity in the central nervous system, a property apparently related to a serotonin-receptor blocking effect similar in magnitude to that of methysergide. Our hypothesis that the effect of propranolol on narcolepsy is a function of its serotonin-blocking properties is supported by the reported effectiveness of methysergide in treating narcolepsy; methysergide clearly ameliorated sleep attacks, like propranolol in our study, whereas its effects on cataplexy varied.