Age-impaired fluid homeostasis depends on the balance of IL-6/IGF-I in the rat supraoptic nuclei.
Adaptive metabolic changes associated with bacterial infections are likely to cause dehydration. Activation of hypothalamic neurons in the supraoptic nucleus that release anti-diuretic arginine-vasopressin in plasma provides water retention. Aging is characterized by arginine-vasopressin neuron hyper-activity and over-expression of pro-inflammatory cytokines like interleukin (IL)-6. Conversely, insulin-like growth factor (IGF)-I, known to exhibit anti-inflammatory properties, decreases with age. We compared activation of arginine-vasopressin neurons in adult (3 months) and aged (22 months) Wistar rats by measuring not only c-fos expression, plasma arginine-vasopressin and diuresis but also the expression of IL-6 and IGF-I in the supraoptic nuclei after intraperitoneal lipopolysaccharide injection. Aged rats displayed a heightened, shorter lasting activation of arginine-vasopressin neurons following lipopolysaccharide as compared to adults. IL-6 mRNA was 3-fold higher while IGF-I mRNA was 10-fold lower in aged than in adult rats. Brain pre-treatment with neutralizing anti-IL-6 antibodies or recombinant IGF-I in aged rats reversed lipopolysaccharide-induced anti-diuresis. These data extend the concept of neuroendocrine-immune interactions to the arginine-vasopressin neuronal system by establishing a relationship between brain IL-6/IGF-I balance and age-associated arginine-vasopressin neuronal dysfunction.
Palin
K
K
Laboratoire PsyNuGen, CNRS UMR5226, Université de Bordeaux, INRA UMR1286, IFR8 Neurosciences, UFR de Pharmacie, 146 rue Léo Saignat, Bordeaux F-33077, France. kpalin@bordeaux.inra.fr
Moreau
M L
ML
Orcel
H
H
Duvoid-Guillou
A
A
Rabié
A
A
Kelley
K W
KW
Moos
F
F
D000375:Aging; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism; D001253:Astrocytes / Q000502:physiology; D001323:Autoantibodies / Q000378:metabolism; D001921:Brain / Q000503:physiopathology; D004231:Diuresis / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000378:metabolism; D013495:Supraoptic Nucleus / Q000503:physiopathology*; D014883:Water-Electrolyte Imbalance / Q000503:physiopathology*
D001323:Autoantibodies; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D011994:Recombinant Proteins; D001127:Arginine Vasopressin; D007334:Insulin-Like Growth Factor I