title: Activation of microglia and astrocytes in the nucleus tractus solitarius during ventilatory acclimatization to 10% hypoxia in unanesthetized mice.
abstract: Nucleus tractus solitarius (NTS) is the integrative sensory relay of autonomic functions in the brainstem. To explore the nonneuronal cellular basis of central chemosensitivity during the first 24 hr of ventilatory acclimatization to hypoxia (VHA), we have investigated glial activation markers in the NTS. Conscious mice (C57/BL6) were placed in a hermetic hypoxia chamber containing a plethysmograph to record ventilation. After 4 days of habituation to the normoxic environment, mice were subjected to physiological hypoxia (10% O2 ) for 1, 6, or 24 hr. To dissociate interactions between microglia and astrocytes, another group received daily minocycline, a microglia activation blocker. By immunochemical localization of astrocytes (GFAP), activated microglia (Cd11b), and total microglia (Iba-1), we identified an oxygen-sensing glial layer in the NTS, in which astrocytes are first activated after 1-6 hr of hypoxia, followed by microglia after 6-24 hr of hypoxia. Minocycline administration suppressed microglial activation and decreased astrocyte activation at 6 hr and VHA at 24 hr of hypoxia. These results suggest that astrocytes contribute to the neuronal response during the first hour of hypoxia, whereas microglial cells, via cross-talk with astrocytes, are involved in the VHA during the first 24 hr of acclimatization.
authors: Neurobiologie Génétique et Intégrative, UPR 3294, Neurobiologie et Développement, Institut de Neurobiologie Alfred Fessard, CNRS, Gif sur Yvette, France.
authors: A
authors: A
authors: Tadmouri
authors: J
authors: J
authors: Champagnat
authors: M P
authors: MP
authors: Morin-Surun
mesh_terms: D000064:Acclimatization; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D039481:CD11b Antigen / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D000860:Hypoxia / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins / Q000378:metabolism; D017628:Microglia / Q000378:metabolism*; D008911:Minocycline / Q000494:pharmacology; D010991:Plethysmography; D012119:Respiration / Q000187:drug effects; D017552:Solitary Nucleus / Q000187:drug effects / Q000473:pathology*; D013997:Time Factors; D014851:Wakefulness
chemical_list: C491049:Aif1 protein, mouse; D039481:CD11b Antigen; D002135:Calcium-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D008840:Microfilament Proteins; D008911:Minocycline
keywords: CD11b; GFAP; Iba-1; minocycline