Interleukin-10 inhibits spontaneous sleep in rabbits

Proinflammatory cytokines, including interleukin-1 beta (IL-1 beta) and tum or necrosis factor-alpha (TNF-alpha) are involved in sleep regulation. IL-1 0 is an anti-inflammatory cytokine that inhibits proinflammatory cytokine p roduction. We hypothesized that IL-10 could attenuate sleep. Thirty-one mal e rabbits were used. Three doses of IL-10 (5 ng, 50 ng, and 250 ng) were in jected intracerebroventricularly during the rest (light) period. One dose o f IL-10 (250, ng) was injected during the active (dark) cycle. Appropriate time-matched control injections of saline were given to the same rabbits on different days. The two highest doses of IL-10 significantly inhibited spo ntaneous nonrapid eye movement sleep if IL-10 was given during the light cy cle. The highest dose of IL-10 (250 ng) also significantly decreased rapid eye movement sleep. IL-10 administered at dark onset had no effect on sleep . The sleep inhibitory properties of IL-10 provide additional evidence for the hypothesis that a br;tin cytokine network is involved in regulation of physiologic sleep.