Effects of purified human interleukin-1 on sleep and febrile response of cats

Abstract

From cats prepared for chronic polygraphic recordings sleep patterns were obtained for 8 hours after: 1) intracerebroventricular (icv) injection of artificial cerebrospinal fluid (aCSF), day 1; 2) icv injection of interleukin-1 (I1-1), day 2; 3) injection of aCSF, 24 h after injection of I1-1, day 3; 4) injection of aCSF, 48 after injection of I1-1, day 4. Three doses of I1-1 were tested. The dose of 10 nmol slightly prolonged sleep, whereas a dose of 40 nmol totally inhibited sleep. Twenty nmol of I1-1 elicited sleep and increased body temperature. Total sleep (TS) time was significantly increased due to the significant increase in non REM (NREM) sleep as compared to the control day 1. REM sleep was also increased, but this increase did not reach statistical significance. Wakefulness (W) was significantly reduced. At this time the cats were febrile. On day 3, a further significant increase in TS occurred. NREM was significantly increased when compared with day 1, whereas the increase in REM sleep was significant when compared to both day 1 and day 2. At this time body temperature was normal. The increase in REM sleep on days 2 and 3 resulted entirely from the significant increase in the number of REM periods. On day 4, W showed tendency to increase while sleeping time decreased; such tendency suggests that sleep increase caused by I1-1 slowly returns to the control levels. Our results, together with the earlier evidence on somnogenic and pyrogenic action of I1-1, suggest that these actions may be temporarily dissociated.