Central Nervous System IL-1 Beta System and Neuropeptide Y mRNAs During IL-1 Beta-Induced Anorexia in Rats

Brain Res Bull. 1997;44(3):311-7. doi: 10.1016/s0361-9230(97)00159-7.

Abstract

Interleukin-1 beta (IL-1 beta) induces anorexia and neuropeptide Y (NPY) increases feeding by direct action in the central nervous system (CNS). IL-1 beta, depending on the dose, attenuates or blocks NPY-induced feeding. This suggests that IL-1 beta-NPY interactions may be involved in IL-1 beta-induced anorexia. Here, RNase protection assays were used to investigate the effects of the chronic intracerebroventricular (ICV) administration of IL-1 beta (at a dose that yields estimated pathophysiological concentrations in the cerebrospinal fluid) on mRNA levels of IL-1 beta system components and NPY in the cerebellum, parietofrontal cortex, hippocampus, hypothalamus, and midbrain. The results show that the chronic ICV administration of IL-1 beta (8.0 ng/24 h for 72 h) differentially induced IL-1 beta system components across brain regions in anorectic rats. IL-1 beta mRNA and IL-1 receptor antagonist (IL-1Ra) mRNA were induced similarly, exhibiting highest and lowest expression levels in the hypothalamus and hippocampus, respectively. IL-1 receptor type I (IL-1RI) mRNA and the soluble form of IL-1 receptor accessory protein (IL-1R AcP II) mRNA were also induced in the hypothalamus and cerebellum. NPY mRNA expression showed a small, but significant decrease in the hypothalamus. Heat-inactivated IL-1 beta (8.0 ng/24 h for 72 h) had no effect on the behavioral or molecular profiles. The results suggest that endogenous upregulation of IL-1 beta contributes to IL-1 beta-induced anorexia, and that modification of NPY mechanisms also may be involved.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Anorexia / chemically induced*
  • Anorexia / physiopathology*
  • Body Weight
  • Cerebellum / chemistry
  • Cerebellum / physiology
  • Cerebral Cortex / chemistry
  • Cerebral Cortex / physiology
  • Dose-Response Relationship, Drug
  • Drinking
  • Eating
  • Gene Expression / drug effects
  • Hippocampus / chemistry
  • Hippocampus / physiology
  • Hypothalamus / chemistry
  • Hypothalamus / physiology
  • Injections, Intraventricular
  • Interleukin-1 / genetics
  • Interleukin-1 / pharmacology*
  • Male
  • Mesencephalon / chemistry
  • Mesencephalon / physiology
  • Neuroimmunomodulation / drug effects
  • Neuropeptide Y / genetics*
  • Proteins / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Receptors, Interleukin
  • Receptors, Interleukin-1 / genetics
  • Receptors, Interleukin-1 Type I

Substances

  • Il1rl2 protein, rat
  • Interleukin-1
  • Neuropeptide Y
  • Proteins
  • RNA, Messenger
  • Receptors, Interleukin
  • Receptors, Interleukin-1
  • Receptors, Interleukin-1 Type I