Neuroscience 2002 Abstract
| Presentation Number: | 850.7 |
|---|---|
| Abstract Title: | Clustering of Kv2.1 Potassium Channels in Spinal Neurons. |
| Authors: |
Muennich, E. A. L.*1
; Ream , L. J.1
; Dewey, D. E.1
; Fyffe, R. E. W.1
1Anatomy, Wright State University, Dayton, OH |
| Primary Theme and Topics |
Motor Systems - Motoneurons |
| Session: |
850. Spinal cord II Poster |
| Presentation Time: | Thursday, November 7, 2002 10:00 AM-11:00 AM |
| Location: | Hall A2-B3 F-33 |
| Keywords: | MOTONEURON, CHOLINERGIC, CHANNEL, MUSCARINIC |
Kv2.1 channel subunits underly delayed rectifier potassium currents that are expressed in neurons throughout the mammalian CNS. We used confocal and electron microscopy to analyze the subcellular localization of these channels in a variety of rat spinal cord neurons, including motoneurons (MNs), interneurons, and dorsal spinocerebellar tract (DSCT) cells, using a commercially available monoclonal antibody against Kv2.1 (Upstate). Kv2.1 immunoreactivity appeared as distinct surface membrane clusters in somatic and proximal dendritic regions. Clusters varied in size and complexity depending on neuron type, with the largest clusters seen on MNs. Quantitative analysis of Kv2.1 channel clusters (n=225 'en face' clusters) on MNs revealed a bimodal size distribution including small (<1.0 mm2) and large (average area about 7.0 mm2) clusters, with an average of about 36 of the large clusters per MN soma. Clusters on DSCT cells and Renshaw cells were much smaller than those on MNs, suggesting cell-type specific factors that regulate the membrane organization of Kv2.1 channels. In MNs, Kv2.1 channel clusters were apposed to large synaptic terminals that express immunoreactivity for the vesicular acetylcholine transporter (VAChT), indicative of cholinergic C-terminals. The Kv2.1 channels also colocalize with labeling against the m2 muscarinic receptor. Ultrastructural analysis confirmed the localization of Kv2.1 immunoreactivity at postsynaptic sites. These data suggest that Kv2.1 channels in MNs are selectively localized at cholinergic C-terminal synapses, which are characterized by subsurface cisternae, and may play a role in regulating postsynaptic responsiveness at these synaptic sites.
Supported by NIH NS25547 to REWF
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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