Timing the excitotoxic induction of heat shock protein 70 transcription.
The time course of heat-shock protein 70 (HSP70) transcriptional induction was compared with neuronal- and non-neuronal-specific mRNAs following intrastriatal quinolinate (QA) injection. Within one hour of QA exposure, immediate-early gene (IEG; c-fos) activation preceded slight increases in glutamic acid decaroxylase (GAD) mRNA levels. However, glial fibrillary acid protein (GFAP) and HSP70 mRNA levels remained constant. After one hour, HSP70 mRNA levels surged 6 fold during a delayed transcriptional phase that was induced between 4-12 hours. This phase was characterized by massive increases in c-fos and GFAP mRNAs while GAD transcripts fell drastically suggestive of neuronal death. Therefore HSP70 genes may play an important role in glial/immune activation following rapid excitotoxic damage by direct injections of quinolinate.
Walker
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Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201.
Carlock
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D000818:Animals; D015152:Blotting, Northern; D003342:Corpus Striatum; D016762:Genes, fos / Q000187:drug effects; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000235:genetics; D005968:Glutamate Decarboxylase / Q000096:biosynthesis / Q000235:genetics; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D007267:Injections; D008297:Male; D009410:Nerve Degeneration / Q000187:drug effects; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D017378:Quinolinic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D014158:Transcription, Genetic / Q000187:drug effects*
D005904:Glial Fibrillary Acidic Protein; D006360:Heat-Shock Proteins; D005968:Glutamate Decarboxylase; D017378:Quinolinic Acid