title: Acute hyperosmotic stimulus-induced Fos expression in neurons depends on activation of astrocytes in the supraoptic nucleus of rats.
abstract: Acute hyperosmolarity induced a time-dependent expression of Fos protein in both neurons and astrocytes of the rat supraoptic nucleus, with peak Fos expression occurring at 45 min in astrocytes and at 90 min in neurons after hypertonic stimulation in vivo. To determine whether the two cell types were activated separately or in an integrated manner, animals were pretreated with fluorocitrate, a glial metabolic blocker or carbenoxolone, a gap junction blocker followed by an acute hypertonic stimulation similar to that of the controls. Antibodies against glial fibrillary acidic protein, connexin 43, vasopressin, and oxytocin were used in serial sections to identify the cellular elements of the supraoptic nucleus. It was found that interruption of astrocyte metabolism with fluorocitrate significantly reduced Fos protein expression in both astrocytes and neurons, whereas blockage of gap junctions with carbenoxolone clearly reduced Fos protein expression in neurons, but not in astrocytes. These results indicate that both neurons and astrocytes in the rat supraoptic nucleus are involved in regulating osmolarity. Astrocytes are activated first, whereas connexin 43 functional hemichannels in SON astrocytes are required for the subsequent activation of the neurons.
authors: Institute of Neuroscience, The Fourth Military Medical University, Xi'an, China.
authors: Hua
authors: H
authors: Yuan
authors: Bei
authors: B
authors: Gao
authors: Li
authors: L
authors: Duan
authors: Shan
authors: S
authors: Jiang
authors: Rong
authors: R
authors: Cao
authors: Ying-Fei
authors: YF
authors: Xiong
authors: Zhi-Ren
authors: ZR
authors: Rao
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002229:Carbenoxolone / Q000494:pharmacology; D002491:Central Nervous System Agents / Q000494:pharmacology; D002951:Citrates / Q000494:pharmacology; D018031:Connexin 43 / Q000378:metabolism; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009994:Osmolar Concentration; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012462:Saline Solution, Hypertonic; D013495:Supraoptic Nucleus / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D002491:Central Nervous System Agents; D002951:Citrates; D018031:Connexin 43; D016760:Proto-Oncogene Proteins c-fos; D012462:Saline Solution, Hypertonic; C007744:fluorocitrate; D002229:Carbenoxolone