Similar genetic mechanisms may underlie sleep-wake states in neonatal and adult rats

Genetic differences in the characteristics of sleep-wake states in adult an imals offer a potential window for examining how the neonatal and adult beh avioural states are related to one another. Our recent finding that adult W istar-Kyoto (WKY) rats show pronounced genetic differences in sleep-wake pa tterns relative to the Wistar (WIS) control strain led us to investigate th e relationship between these behavioural states in neonates and adults in a longitudinal study in these two strains of rats. Similar pronounced differ ences in the sleep-wake states were observed between WKY and WIS rats in ne onatal and in adult animals. At both ages, WKY rats spent more time in acti vesleep (AS) and rapid eye movement sleep (REMS) and less time in quiet sle ep (QS) and non-REM sleep (NREMS) than WIS rats, and the sleep-wake states were more fragmented in neonatal and adult WKY rats. While it is not known how neonatal AS and QS are physiologically related to adult REMS and NREMS, respectively, the finding of similar differences in the amounts of sleep-w ake states in neonatal and adult WKY and WIS rats argues strongly that at s ome level they are controlled by similar genetic as well as cellular/physio logical mechanisms. NeuroReport 12:3085-3089 (C) 2001 Lippincott Williams & Wilkins.