title: Lipopolysaccharide and IL-1 alpha activate CNS pathways as measured by NK cell activity.
abstract: The effect of lipopolysaccharide (LPS) on murine unstimulated and prestimulated natural killer (NK) cells and its ability to serve as an unconditioned stimulus was investigated. LPS injection induced a statistically significant increase in NK cell activity when compared with saline-treated control groups. To demonstrate the existence of communication between the peripheral immune system and the central nervous system (CNS), we used a single-trial conditioning paradigm in which camphor served as the conditioned stimulus (CS) and LPS as the unconditioned stimulus (US). Once a CS/US association is made, exposure of animals to the CS alone results in the conditioned response (i.e., increase in NK cell activity). Using 50 micrograms of LPS as the US produced a low but significant increase in NK cell activity when compared to control groups. However, 10 micrograms of LPS did not show a significant increase in NK cell activity. We also observed that interleukin-1 alpha (IL-1 alpha) injected intracisternally can serve as a US to condition a central neuroendocrine pathway. Because the dose of IL-1 alpha employed was too small to raise NK cell activity in the spleen, the NK cells themselves were formally not subjected to conditioning. These observations suggest that LPS and IL-1 alpha conditions the brain and that NK cell activity can be used as an indicator system to detect neuroendocrine signals arising from the activated pathway(s).
authors.affiliation: Department of Microbiology, University of Alabama at Birmingham 35294, USA.
authors.forename: S
authors.initials: S
authors.lastname: Demissie
authors.forename: C F
authors.initials: CF
authors.lastname: Rogers
authors.forename: N S
authors.initials: NS
authors.lastname: Hiramoto
authors.forename: V K
authors.initials: VK
authors.lastname: Ghanta
authors.forename: R N
authors.initials: RN
authors.lastname: Hiramoto
mesh_terms: D000818:Animals; D002164:Camphor / Q000494:pharmacology; D002490:Central Nervous System / Q000166:cytology / Q000187:drug effects*; D002946:Cisterna Magna; D003214:Conditioning, Classical / Q000187:drug effects; D004731:Endotoxins / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007267:Injections; D007275:Injections, Intravenous; D007375:Interleukin-1 / Q000008:administration & dosage / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009434:Neural Pathways / Q000187:drug effects; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D013268:Stimulation, Chemical
chemical_list: D004731:Endotoxins; D007375:Interleukin-1; D008070:Lipopolysaccharides; C044101:endotoxin, Escherichia coli; D002164:Camphor