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GABA-activated Single-channel and Tonic Currents in Rat Brain Slices
Published on: July 17, 2011
Subcellular localization of GABA(B) receptor subunits in rat visual cortex.
Y Gonchar1, L Pang, B Malitschek
1Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
The Journal of Comparative Neurology
|February 15, 2001
Summary
This study reveals the precise locations of gamma-aminobutyric acid B (GABA(B)) receptors in the visual cortex, identifying their presence in synapses and even the nucleus. These findings suggest novel roles for GABA(B) receptors in neuronal function and gene expression.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Previous studies indicated gamma-aminobutyric acid B (GABA(B)) receptor roles in visual cortex inhibition.
- The precise subcellular localization of GABA(B) receptors in different cortical neuron types and synapses remained unclear.
Purpose of the Study:
- To directly determine the subcellular localization of GABA(B) receptor subunits (GABA(B)R1a/b and GABA(B)R2) in the rat visual cortex.
- To investigate the presence and co-localization of these subunits in various neuronal compartments and synapse types.
Main Methods:
- Utilized antibodies against GABA(B) receptor subunits (GABA(B)R1a/b and GABA(B)R2).
- Employed light and electron microscopy with immunoperoxidase and immunogold labeling techniques.
- Analyzed immunoreactivity in pyramidal and GABAergic neurons (parvalbumin, calretinin, somatostatin-positive).
Main Results:
- Both GABA(B)R1a/b and GABA(B)R2 subunits were found in cell bodies, dendrites, nucleus, cytoplasm, and cell surface membranes of cortical neurons.
- Colocalization of both subunits was observed in excitatory and inhibitory synapses, as well as extrasynaptic membranes.
- GABA(B) receptors were concentrated postsynaptically in GABAergic synapses and found in both pre- and postsynaptic membranes of type 1 synapses.
Conclusions:
- GABA(B) receptor subunits form functional heteromeric assemblies at both excitatory and inhibitory synapses.
- Nuclear localization suggests a novel role for neurotransmitter receptors in regulating gene expression.
- The widespread expression implies diverse roles for GABA(B) receptors in synaptic transmission and neuronal regulation, including potential modulation of glutamate release.
