Tumor necrosis factor receptor fragment attenuates interferon-gamma-induced non-REM sleep in rabbits

Although the somnogenic actions of interferon-alpha (IFN alpha) and IFN bet a have been reported, the sleep effects of IFN-gamma remained unknown. Thus , we investigated the effects of intracerebroventricular injection of human IFN gamma on sleep in rabbits. IFN gamma dose-dependently increased nonrap id eye movement sleep (NREMS), electroencephalographic slow wave activity a nd brain temperature (Tbr). These effects were markedly attenuated after th e heat treatment of IFN gamma. IFN gamma suppressed rapid eye movement slee p if given during the light period, but not if given at dark onset. Althoug h a tumor necrosis factor receptor fragment did not affect any sleep parame ters when given at dark onset, it significantly attenuated IFN gamma -induc ed NREMS and Tbr. These data suggest that IFN gamma may be involved in the sleep responses during infection. Further, IFN gamma may have a synergistic interaction with intrinsic TNF alpha in the brain. (C) 2001 Elsevier Scien ce B.V. All rights reserved.