Mice lacking the TNF 55 kDa receptor fail to sleep more after TNFalpha treatment.

Tumor necrosis factor (TNF) is a well characterized sleep-regulatory substance. To study receptor mechanisms for the sleep-promoting effects of TNF, sleep patterns were determined in control and TNF 55 kDa receptor knock-out (TNFR-KO) mice with a B6 x 129 background after intraperitoneal injections of saline or murine TNFalpha. The TNFR-KO mice had significantly less baseline sleep than the controls. TNFalpha dose-dependently increased non-rapid eye movement sleep (NREMS) in the controls but did not influence sleep in TNFR-KO mice. Although TNFR-KO mice failed to respond to TNFalpha, they had an increase in NREMS and a decrease in rapid eye movement sleep after interleukin-1beta treatment. These results indicate that TNFalpha affects sleep via the 55 kDa receptor and provide further evidence that TNFalpha is involved in physiological sleep regulation. Current results also extend the list of species to mice in which TNFalpha and interleukin-1beta are somnogenic.