Neuronal activity up-regulates astroglial gene expression.
Neuronal gene expression is known to be modulated by functional activity. This modulation is thought to play a key role in determining the differentiation of developing neurons and regulating the operation of mature neurons. Here we describe a regulation of astroglial gene expression by neuronal activity. We report that intense neuronal activity (electrically induced seizures) in rat hippocampus leads to rapid and dramatic increases in mRNA for glial fibrillary acidic protein (GFAP), an astroglia-specific intermediate filament protein. GFAP mRNA levels increased at sites of stimulation as well as in areas that were synaptically activated by the resultant seizures. When seizures were induced repetitively for many days, levels of GFAP mRNA remained chronically elevated. However, GFAP mRNA returned to control levels within a few days after the cessation of stimulation. The coupling between astroglial gene expression and neuronal activity may be a mechanism through which neuronal activity modulates the function of supporting cells that are responsible for regulating the extracellular microenvironment of the brain.
Steward
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Department of Neuroscience, University of Virginia Health Sciences Center, Charlottesville 22908.
Torre
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Tomasulo
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Lothman
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D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D004558:Electric Stimulation; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics*; D006624:Hippocampus / Q000502:physiology* / Q000503:physiopathology; D007696:Kindling, Neurologic; D008297:Male; D009410:Nerve Degeneration; D009474:Neurons / Q000502:physiology*; D009693:Nucleic Acid Hybridization; D011712:Pyramidal Tracts / Q000502:physiology* / Q000503:physiopathology; D015347:RNA Probes; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D012640:Seizures / Q000503:physiopathology
D005904:Glial Fibrillary Acidic Protein; D015347:RNA Probes; D012333:RNA, Messenger