Interleukin 1beta enhances non-rapid eye movement sleep and increases c-Fos protein expression in the median preoptic nucleus of the hypothalamus.
| Publication Type | Academic Article |
| Authors | Baker F, Shah S, Stewart D, Angara C, Gong H, Szymusiak R, Opp M, McGinty D |
| Journal | Am J Physiol Regul Integr Comp Physiol |
| Volume | 288 |
| Issue | 4 |
| Pagination | R998-R1005 |
| Date Published | 12/16/2004 |
| ISSN | 0363-6119 |
| Keywords | Interleukin-1, Preoptic Area, Proto-Oncogene Proteins c-fos, Sleep, REM |
| Abstract | Interleukin 1beta (IL-1) is a key mediator of the acute phase response in an infected host and acts centrally to coordinate responses to an immune challenge, such as fever and increased non-rapid eye movement (NREM) sleep. The preoptic area (POA) is a primary sleep regulatory center in the brain: the ventrolateral POA (VLPO) and median preoptic nucleus (MnPN) each contain high numbers of c-Fos protein immunoreactive (IR) neurons after sleep but not after waking. We hypothesized that IL-1 mediates increased NREM sleep through activation of these sleep-active sites. Rats injected intracerebroventricularly with IL-1 (10 ng) at dark onset spent significantly more time in NREM sleep 4-5 h after injection. This increase in NREM sleep was associated with increased numbers of Fos-IR neurons in the MnPN, but not in the VLPO. Fos IR in the rostral MnPN was significantly increased 2 h post IL-1 injection, although the percentage of NREM sleep in the preceding 2 h was the same as controls. Fos IR was also increased in the extended VLPO 2 h postinjection. Finally, Fos IR in the MnPN did not differ significantly between IL-1 and vehicle-treated rats that had been sleep deprived for 2 h postinjection, but it was increased in VLPO core. Taken together, these results suggest that Fos IR in the MnPN after IL-1 is not independent of behavioral state and may require some threshold amount of sleep for its expression. Our results support a hypothesis that IL-1 enhances NREM sleep, in part, through activation of neurons in the MnPN of the hypothalamus. |
| DOI | 10.1152/ajpregu.00615.2004 |
| PubMed ID | 15604300 |