Karger Publishers, Neuropsychobiology, 4(65), p. 195-205, 2012
DOI: 10.1159/000336998
Full text: Unavailable
<b><i>Objectives:</i></b> Neuropeptide S (NPS) exerts a dual arousal and anxiolytic effect in rodents, which may indicate the potential of a novel class of therapeutic agents in psychiatry. The purpose of this study is to fully describe the nature of electroencephalogram (EEG)-defined waking that mediates these arousal effects. <b><i>Methods:</i></b> Effects of the intracerebroventricular infusion of NPS at 2 different doses were characterized over 20 h on sleep-wake architecture and EEG spectral components in rats that were chronically implanted with epidural electrodes for continuous measurement of sleep polygraphic and EEG variables. <b><i>Results:</i></b> NPS (1 and 10 nmol) increased active waking (+88 and +87%, respectively), decreased light slow-wave sleep (lSWS) (–84 and –68%, respectively), deep slow-wave sleep (dSWS) (–47 and –33%, respectively) and rapid-eye-movement sleep (–71 and –70%, respectively) during the first 2 h after infusion. The wake-promoting effect of NPS is consistent with a marked lengthening in latency to sleep onset, a decrease in the number of state transitions from wakefulness to lSWS, and a delayed lSWS compensatory response. Interestingly, NPS significantly enhanced waking EEG theta oscillations and slow wave activity during dSWS. <b><i>Conclusion:</i></b> The findings suggest that NPS enhanced a consolidated waking associated with a subsequent compensatory EEG slow-wave homeostatic drive rather than rebound sleep duration. The characteristics of NPS-induced waking coupled with enhanced EEG theta oscillations without rebound in sleep are desirable therapeutic features in wake-promoting agents.