Interleukin-15 and interleukin-2 enhance non-REM sleep in rabbits.
Interleukin (IL)-15 and -2 share receptor- and signal-transduction pathway (Jak-STAT pathway) components. IL-2 is somnogenic in rats but has not been tested in other species. Furthermore, the effects of IL-15 on sleep have not heretofore been described. We investigated the somnogenic actions of IL-15 in rabbits and compared them with those of IL-2. Three doses of IL-15 or -2 (10, 100, and 500 ng) were injected intracerebroventriculary at the onset of the dark period. In addition, 500 ng of IL-15 and -2 were injected 3 h after the beginning of the light period. IL-15 dose dependently increased non-rapid eye movement sleep (NREMS) and induced fever. IL-15 inhibited rapid eye movement sleep (REMS) after its administration during the light period; however, all doses of IL-15 failed to affect REMS if given at dark onset. IL-2 also dose dependently increased NREMS and fever. IL-2 inhibited REMS, and this effect was observed only in the light period. IL-15 and -2 enhanced electroencephalographic (EEG) slow waves during the initial 9-h postinjection period, then, during hours 10-23 postinjection, reduced EEG slow-wave activity. Current data support the notion that the brain cytokine network is involved in the regulation of sleep.
Kubota
T
T
College of Veterinary Medicine, Department of VCAPP, Washington State University, Pullman, WA 99164-6520, USA.
Brown
R A
RA
Fang
J
J
Krueger
J M
JM
D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects; D007276:Injections, Intraventricular; D019409:Interleukin-15 / Q000008:administration & dosage / Q000494:pharmacology*; D007376:Interleukin-2 / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D011817:Rabbits; D012894:Sleep Stages / Q000187:drug effects* / Q000502:physiology*
D019409:Interleukin-15; D007376:Interleukin-2