The effect of naloxone on the symptoms of narcolepsy.

The effect of Naloxone (0.4 mg i.v.) was studied in 10 patients suffering from narcolepsy. The diurnal polysomnographic recordings showed that Naloxone leads to an increase in the latency of REM sleep (P less than 0.05), to a shortening of its total duration and to a decrease in the average amount of phasic manifestations in 1 min. of REM sleep (P less than 0.05). The Polygraphic sleepiness score for REM sleep decreased significantly (P less than 0.01). Naloxone led also to the disappearance of stages 3 and 4 NREM sleep, and to an increase in the total duration of stage 1 NREM sleep. Naloxone caused no change in the total performance in Bourdon's test; though it did enhance attention. There were no changes in the subjective perception of the state of arousal or of the psychomotor tempo. It was found no post-Naloxone alterations of blood pressure, body temperature, pulse or pupillary diameter. The above findings support the hypothesis that an hyperactive endorphinergic system participates in the pathophysiology of narcolepsy.