851376-05-1

JNJ-18038683 dose-dependently suppresses REM sleep mainly during the first 4 h after the treatment. The duration of REM sleep is significantly decreased from the dose of 1 mg/kg onward (P<0.05) during the first 4 h after oral administration. Concomitantly, the REM sleep latency tends to be prolonged in a dose-related manner with a significant increase in REM latency occurring only at the highest dose tested (10 mg/kg; P<0.05). These alterations in REM sleep seem to be state-specific. A separate study is conducted to determine whether repeated administration of JNJ-18038683 for 7 days would result in an adaptation of the EEG sleep response in particular on REM sleep in rats during the course of the treatment and after its discontinuation. JNJ-18038683 is administered for 7 consecutive days (1 mg/kg s.c. per day) at 2 h into the light phase. On the first day of treatment, JNJ-18038683 produces a significant decrease in the time spent in REM sleep during the first 8 h after the injection and a prolongation of the REM sleep latency. The REM sleep latency is increased during the 7-day repeated treatment and is normalized on the first recovery day after cessation of treatment. The significant decrease in REM sleep time is maintained during the 7-day repeated treatment, with a rebound occurring on the first recovery day after treatment discontinuation. The NREM sleep latency and the total NREM sleep time are not affected during the entire treatment^[1].