ROLE OF THE LOCUS-COERULEUS IN THE SLEEP REBOUND FOLLOWING 2 DIFFERENT SLEEP-DEPRIVATION METHODS IN THE RAT

The aim of the present study was to assess the involvement of the locu s coeruleus in the paradoxical sleep rebound following sleep deprivati on in the rat. Animals were sleep-deprived for 10 h before, and after, specific N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-1) lesioni ng of the noradrenergic-locus coeruleus system. Sleep deprivation was produced using either an instrumental (water tank) or pharmacological (methylamphetamine) method. After lesioning, the rats submitted to the instrumental method showed a significant decrease in the paradoxical and slow-wave sleep rebounds (-54% and -78%, respectively), while anim als receiving metamphetamine did not. Our results suggest that the nor adrenergic system of the locus coeruleus is a relevant component of th e sleep rebound mechanisms. However, the extent of involvement is depe ndent on the sleep deprivation method used.