INTERLEUKIN-10 (CYTOKINE SYNTHESIS INHIBITORY FACTOR) ACTS IN THE CENTRAL-NERVOUS-SYSTEM OF RATS TO REDUCE SLEEP

Interleukin-10 (IL-10), originally designated a cytokine synthesis inh ibitory factor, inhibits the synthesis of the pro-inflammatory cytokin es IL-1 and tumor necrosis factor by stimulated human and mouse monocy tes/macrophages; these cytokines are involved in the regulation of sle ep. To determine if IL-10 reduces spontaneous sleep, we injected murin e recombinant IL-IO intracerebroventricularly into rats prior to light onset. Non-rapid eye movements sleep was reduced. The behavioral resp onses to IL-IO were abolished by heat-inactivation of this cytokine. W e believe these to be the first observations of central nervous system actions for this cytokine. These results further support the hypothes is that cytokines are involved in the regulation of sleep, and suggest an additional mechanism whereby sleep may be altered in response to a n activated immune system.