Anti-interleukin-1 beta reduces sleep and sleep rebound after sleep deprivation in rats.

Interleukin-1 (IL-1) is somnogenic and is hypothesized to be involved in physiological sleep regulation. Antibodies directed against rat IL-1 beta were used to further elucidate possible contributions of IL-1 to sleep regulation. Rabbit anti-rat IL-1 beta (anti-IL-1 beta) was injected intracerebroventricularly into normal rats 15 min before light onset. A 20-microgram dose of anti-IL-1 beta reduced non-rapid-eye-movement (NREM) sleep by 60 min during the subsequent 12-h slight period. There was no effect on rapid eye movement sleep after this dose of anti-IL-1 beta. The effects of anti-IL-1 beta on the enhancement of sleep after periods of sleep deprivation were also determined. When rats were deprived of sleep for 3-h beginning at light onset, the amount of time spent in NREM sleep increased for the remaining 9 h of the light period, regardless of whether control intracerebroventricular injections of pyrogen-free saline or rabbit immunoglobulin G were given during the deprivation period. However, when 20 micrograms anti-IL-1 beta were injected intracerebroventricularly during the sleep deprivation period, the expected NREM sleep rebound was completely blocked. Collectively, these data provide additional support for the hypothesis that IL-1 is involved in regulation of physiological sleep-wake activity.