Differential Na+ channel beta 1 subunit mRNA expression in stellate and flat astrocytes cultured from rat cortex and cerebellum: a combined in situ hybridization and immunocytochemistry study.
Astrocytes have been shown to express voltage-sensitive Na+ channels, but the molecular structure of these channels is not yet known. Recent studies have demonstrated the expression of rat brain voltage-sensitive Na+ channel mRNAs in astrocytes. In this study, we used a combined non-radioactive in situ hybridization/immunocytochemistry method to investigate the expression of voltage-sensitive Na+ channel beta 1 subunit (Na beta 1) mRNA in definitively identified, GFAP-positive astrocytes cultured from two different regions of the rat brain, cerebrum and cerebellum. In general, two morphologically distinct types of GFAP-positive astrocytes were observed in culture: flat, fibroblast-like and stellate, process-bearing. We observed a differential expression of Na beta 1 mRNA in GFAP-positive astrocytes: 1) stellate astrocytes expressed Na beta 1 mRNA, although the level of Na beta 1 mRNA expression was variable, and 2) flat astrocytes generally did not express Na beta 1 mRNA. Moreover, Bergmann-like cells from cerebellum did not express Na beta 1 mRNA, while the granule cells associated with Bergmann-like cell expressed Na beta 1 mRNA. These observations indicate that Na beta 1 mRNA is differentially expressed in rat astrocytes with various morphologies in vitro.
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Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Waxman
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SG
D000818:Animals; D001253:Astrocytes / Q000737:chemistry*; D002478:Cells, Cultured / Q000737:chemistry; D002531:Cerebellum / Q000166:cytology; D002540:Cerebral Cortex / Q000166:cytology; D005786:Gene Expression Regulation / Q000235:genetics*; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015222:Sodium Channels / Q000235:genetics*
D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; D015222:Sodium Channels