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Reduced retinal activity increases GFAP immunoreactivity in rat lateral geniculate nucleus
K S Canady1, J F Olavarria, E W Rubel
1Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-HNS, University of Washington, Seattle 98195.
Brain Research
|November 14, 1994
Summary
Astrocytes in the rat lateral geniculate nucleus (LGN) rapidly increase glial fibrillary acidic protein (GFAP) after reduced neuronal activity. This suggests neural activity dynamically regulates astrocytes in sensory systems.
Area of Science:
- Neuroscience
- Cellular Neuroscience
- Glial Biology
Background:
- Astrocytic processes are dynamically regulated by neuronal electrical activity in the chick cochlear nucleus.
- Astrocytes play crucial roles in synaptic function and plasticity.
Purpose of the Study:
- To investigate if astrocytes in the rat lateral geniculate nucleus (LGN) respond to changes in afferent visual neuronal activity.
- To determine the time course and mechanisms of astrocyte reactivity to neuronal activity deprivation.
Main Methods:
- Enucleation to eliminate afferent input to the LGN.
- Intraocular injections of tetrodotoxin to reversibly block optic nerve activity.
- Immunohistochemistry to assess glial fibrillary acidic protein (GFAP) immunoreactivity.
Main Results:
- GFAP immunoreactivity in LGN astrocytes increased within 6 hours of enucleation.
- Similar GFAP increases were observed after tetrodotoxin-induced optic nerve activity blockade.
- The rapid response to activity deprivation was less pronounced than the gliotic reaction seen 3 weeks post-deafferentation.
Conclusions:
- Astrocytes in the rat LGN are rapidly regulated by the electrical activity of local neurons.
- Activity-dependent regulation of astrocytes may be a general mechanism in vertebrate sensory systems.
- This highlights a role for astrocytes in activity-dependent synaptic regulation.