title: Hyperosmotic induction of aquaporin expression in rat astrocytes through a different MAPK pathway.
abstract: Water homeostasis of the nervous system is important during neural signal transduction. Astrocytes are crucial in water transport in the central nervous system under both physiological and pathological conditions. To date, five aquaporins (AQP) have been found in rat brain astrocytes. Most studies have focused on AQP4 and AQP9, however, little is known about the expression of AQP3, -5, and -8 as well as their regulating mechanism in astrocytes. The expression patterns of AQP3, -5, and -8 in astrocytes exposed to hyperosmotic solutions were examined to clarify the roles of AQP3, -5, and -8 in astrocyte water movement. The expression of AQP4 and AQP9 under the same hyperosmotic conditions was also investigated. The AQP4 and AQP9 expressions continuously increased until 12 h after hyperosmotic solution exposure, whereas the AQP3, -5, and -8 expressions continued to increase until 6 h after hyperosmotic solution exposure. The different AQPs decreased at corresponding time points (24 h for AQP4 and AQP9; 12 h for AQP3, -5, and -8 after hyperosmotic solution exposure). The ERK inhibitor can attenuate the expression of AQP3, -5, and -8 after hyperosmotic solution exposure. The p38 inhibitor can inhibit the AQP4 and AQP9 expressions in cultured astrocytes. AQP expression is directly related to the extracellular hyperosmotic stimuli. Moreover, different AQPs can be regulated by a distinct MAPK signal transduction pathway.
authors.affiliation: Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, People's Republic of China.
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.forename: Wei Hua
authors.initials: WH
authors.lastname: Yu
authors.forename: Fei
authors.initials: F
authors.lastname: Zhuo
authors.forename: Guo Ping
authors.initials: GP
authors.lastname: Qiu
authors.forename: Jian Hua
authors.initials: JH
authors.lastname: Ran
authors.forename: Shan Quan
authors.initials: SQ
authors.lastname: Sun
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D020346:Aquaporins / Q000235:genetics* / Q000378:metabolism; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D061251:Primary Cell Culture; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014867:Water / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D020346:Aquaporins; D020033:Protein Isoforms; D047428:Protein Kinase Inhibitors; D014867:Water; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases