title: Adrenomedullin expression is up-regulated by acute hypobaric hypoxia in the cerebral cortex of the adult rat.
abstract: Hypobaric hypoxia can produce neuropsychological disorders such as insomnia, dizziness, memory deficiencies, headache and nausea. Here we report the changes in adrenomedullin (AM) expression observed in rats exposed to hypobaric hypoxia and different times of reoxygenation. AM immunoreactivity was transiently elevated in the cerebral cortex after 7 h of exposure to a simulated altitude of 8325 m (27 000 ft). This higher expression was seen in all pyramidal cells and in a subset of small interneurons. AM-positive nonpyramidal neurons contained also calbindin and calretinin, but no parvalbumin immunoreactivity, thus identifying them as bipolar and double bouquet cells. Small blood vessels and related astroglia also became immunoreactive following the hypobaric insult. AM up-regulation decreased progressively with the time of reoxygenation, reaching almost control levels after 5 days. Real-time PCR quantification of AM mRNA and Western blotting confirmed the up-regulation of AM expression following hypobaria. In addition, hypobaria modulates alternative splicing of the AM gene resulting in a higher production of AM. Our data show that AM expression regulation constitutes a cortical response to hypobaria, suggesting that AM modulation may provide new therapeutic avenues to prevent and/or treat the symptoms produced by hypobaria.
authors: Department of Cellular, Molecular, and Developmental Neurobiology, Instituto Cajal, CSIC, Madrid, Spain.
authors: Julia
authors: J
authors: Serrano
authors: Ana Patricia
authors: AP
authors: Fernández
authors: Jaime
authors: J
authors: Sánchez
authors: José
authors: J
authors: Rodrigo
authors: Alfredo
authors: A
authors: Martínez
mesh_terms: D053607:Adrenomedullin / Q000096:biosynthesis*; D000532:Altitude Sickness / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002540:Cerebral Cortex / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D000860:Hypoxia / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; D053607:Adrenomedullin