title: Expression of Na(+)-K(+)-Cl(-) cotransporter in rat brain during development and its localization in mature astrocytes.
abstract: Na(+)-K(+)-Cl(-) cotransporter has been proposed to play an important role in the regulation of intracellular Cl(-) concentration in neurons during development. In this study, the expression pattern of the cotransporter in different regions of rat brain was examined at birth (P0), postnatal days 7 (P7), P14, P21, and adult by Western blotting analysis. In cortex, thalamus, cerebellum and striatum, the cotransporter expression level was low at P0 and significantly increased at P14 (P<0.05). The expression peaked at P21 and was maintained at the same level in adulthood. However, in hippocampus, a peak level of the cotransporter expression was detected in adult brain. The immunocytochemistry study of adult rat brain revealed that an intense staining of the Na(+)-K(+)-Cl(-) cotransporter protein was observed in dendritic processes of CA1-CA3 hippocampal pyramidal neurons. In contrast, abundant immuno-reactive signals of the cotransporter were found in somata of thalamic nucleus. Immunofluorescence double staining demonstrates that the Na(+)-K(+)-Cl(-) cotransporter was expressed in astrocytes within cortex, corpus callosum, hippocampus and cerebellum. In addition, co-localization of the cotransporter and glial fibrillary acidic protein (GFAP), or with aquaporin 4, was found in perivascular astrocytes of cortical cortex and white matter. The results indicate that a time-dependent expression of the Na(+)-K(+)-Cl(-) cotransporter protein occurs not only in cortex but also in hippocampus, striatum, thalamus and cerebellum. In addition, the cotransporter is expressed in astrocytes and perivascular astrocytes of adult rat brain.
authors.affiliation: Department of Neurological Surgery, University of Wisconsin Medical School, 600 Highland Ave., Madison, WI 53792, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Yan
authors.forename: R J
authors.initials: RJ
authors.lastname: Dempsey
authors.forename: D
authors.initials: D
authors.lastname: Sun
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D051401:Aquaporin 4; D020346:Aquaporins / Q000378:metabolism; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism*; D018118:Chloride Channels / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D007424:Intracellular Fluid / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D028021:Sodium-Potassium-Chloride Symporters; D013788:Thalamus / Q000166:cytology / Q000378:metabolism
chemical_list: C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D020346:Aquaporins; D002352:Carrier Proteins; D018118:Chloride Channels; D002712:Chlorides; D005904:Glial Fibrillary Acidic Protein; D028021:Sodium-Potassium-Chloride Symporters; D010751:Phosphopyruvate Hydratase