Central beta-amyloid peptide-induced peripheral interleukin-6 responses in mice.
beta-Amyloid peptides (Abetas) share with lipopolysaccharide, a potent pro-inflammatory agent, the property of stimulating glial cells or macrophages to induce various inflammatory mediators. We recently reported that central administration of lipopolysaccharide induces peripheral interleukin-6 responses via both the central and peripheral norepinephrine system. In this study, the effect of intracerebroventricular injection of various synthetic Abetas on plasma interleukin-6 levels was examined in mice. Abeta(1-42) dose-dependently increased plasma interleukin-6 levels: 'aged' Abeta(1-42) was more effective than fresh, whereas Abeta(42-1) had no effect. 'Aged' Abeta(1-42) (205 pmol/mouse i.c.v.)-induced plasma interleukin-6 peaked at 2 h post injection, which is earlier than the peak time of the Abeta(1-42)-induced brain interleukin-6, tumor necrosis factor-alpha and interleukin-1beta levels, which was 4, 4 and 24 h, respectively. Among various peripheral organs, Abeta(1-42) (205 pmol/mouse i.c.v.) significantly increased interleukin-6 mRNA expression in lymph nodes and liver. Abeta(1-42) (205 pmol/mouse i.c.v.) significantly increased norepinephrine turnover in both hypothalamus and spleen. Either central or peripheral norepinephrine depletion effectively inhibited the Abeta(1-42)-induced peripheral interleukin-6 response. Pretreatment with prazosin (alpha(1)-adrenergic antagonist), yohimbine (alpha(2)-adrenergic antagonist), and ICI-118,551 (beta(2)-adrenergic antagonist), but not with betaxolol (beta(1)-adrenergic antagonist), inhibited Abeta(1-42)-induced plasma interleukin-6 levels. These results demonstrate that centrally administered Abeta(1-42) effectively induces the systemic interleukin-6 response which is mediated, in part, by central Abeta(1-42)-induced activation of the central and the peripheral norepinephrine systems.
Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon, South Korea. dksong@sun.hallym.ac.kr
D K
DK
Song
Y B
YB
Im
J S
JS
Jung
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Cho
H W
HW
Suh
Y H
YH
Kim
D016229:Amyloid beta-Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D007276:Injections, Intraventricular; D007375:Interleukin-1 / Q000235:genetics; D015850:Interleukin-6 / Q000097:blood* / Q000235:genetics*; D007700:Kinetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009638:Norepinephrine / Q000378:metabolism*; D016627:Oxidopamine / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013329:Structure-Activity Relationship; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D016229:Amyloid beta-Peptides; D007375:Interleukin-1; D015850:Interleukin-6; D010446:Peptide Fragments; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016627:Oxidopamine; D009638:Norepinephrine