Corticotropin-releasing factor (CRF) increases paradoxical sleep (PS) rebound in PS-deprived rats

The intracerebroventricular injection (1 microgram) of murine corticotropin-releasing factor (r-CRF) to rats after 72 h of sleep deprivation markedly postponed the sleep onset, reduced slow wave sleep and prolonged the duration of paradoxical sleep (PS) episodes. Moreover, CRF is-to our knowledge-the first compound to be able to further prolong PS in a condition (sleep deprivation) in which its duration is already increased. Our findings raise the possibility that CRF might play a physiological role in the regulation of the sleep-wakefulness cycle.