INHIBITION OF BRAIN INTERLEUKIN-1 ATTENUATES SLEEP REBOUND AFTER SLEEP-DEPRIVATION IN RABBITS

It is hypothesized that interleukin-1 (IL-1) is involved in physiologi cal sleep. If this hypothesis is correct, inhibition of IL-1 should at tenuate sleep responses after sleep deprivation. We tested the effect of intracerebroventricular or intravenous injection of an IL-1 inhibit or, an IL-1 receptor fragment (IL-1RF), on sleep rebound after sleep d eprivation in rabbits. Six hours of total sleep deprivation significan tly increased non-rapid eye movement sleep (NREMS) and enhanced electr oencephalogram slow-wave activity during NREMS. Intracerebroventricula r treatment with the IL-1RF (50 mu g) significantly attenuated the sle ep responses after sleep deprivation. Furthermore, 1.0 mg/kg iv inject ion of the IL-1RF significantly suppressed spontaneous NREMS in rabbit s that were not sleep deprived. However, intravenous administration of the IL-1RF (1.0 mg/kg) failed to attenuate the sleep responses follow ing the 6-h sleep deprivation period. These results support the hypoth esis that central pools of IL-1 are important for physiological sleep regulation.