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Distinct axo-somato-dendritic distributions of three potassium channels in CA1 hippocampal pyramidal cells.

Kirizs T, Kerti-Szigeti K, Lorincz A, Nusser Z - Eur. J. Neurosci. (2014)

Bottom Line: The Kv2.1 subunit was found in somatic, proximal dendritic and AIS plasma membranes at approximately the same densities.A quasi-linear increase in the Kir3.2 subunit density along the dendrites of PCs was detected, showing no significant difference between apical dendritic shafts, oblique dendrites or dendritic spines at the same distance from the soma.Our results demonstrate that each subunit has a unique cell-surface distribution pattern, and predict their differential involvement in synaptic integration and output generation at distinct subcellular compartments.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony Street 43, Budapest, Hungary.

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Immunofluorescent localisation of the Kv2.1 subunit in the CA1 region of the rat hippocampus. (A–C) Low-magnification view of the CA1 area double-labelled for the Kv2.1 (A) and the Nav1.6 (B) subunits. (A and D) Identical immunofluorescent labelling pattern obtained with two antibodies recognising different, non-overlapping parts of the Kv2.1 subunit indicates that the immunoreaction is specific. Arrows point to the somata of interneurons. (E–G) High-magnification images from the SP demonstrate that the immunolabelling for the Kv2.1 subunit is associated with somatic and proximal dendritic plasma membranes of CA1 PCs, as well as with AISs intensely labelled for the Nav1.6 subunit. (I–K) Higher magnification views of the boxed areas in E–G show punctate, non-uniform labelling for the Kv2.1 subunit along the Nav1.6-immunopositive AIS. Scale bars, 100 μm (A–D), 10 μm (E–G), 5 μm (I–K).
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fig03: Immunofluorescent localisation of the Kv2.1 subunit in the CA1 region of the rat hippocampus. (A–C) Low-magnification view of the CA1 area double-labelled for the Kv2.1 (A) and the Nav1.6 (B) subunits. (A and D) Identical immunofluorescent labelling pattern obtained with two antibodies recognising different, non-overlapping parts of the Kv2.1 subunit indicates that the immunoreaction is specific. Arrows point to the somata of interneurons. (E–G) High-magnification images from the SP demonstrate that the immunolabelling for the Kv2.1 subunit is associated with somatic and proximal dendritic plasma membranes of CA1 PCs, as well as with AISs intensely labelled for the Nav1.6 subunit. (I–K) Higher magnification views of the boxed areas in E–G show punctate, non-uniform labelling for the Kv2.1 subunit along the Nav1.6-immunopositive AIS. Scale bars, 100 μm (A–D), 10 μm (E–G), 5 μm (I–K).

Mentions: For immunofluorescent localisation of the Kv2.1 subunit in the CA1 area, two antibodies recognising non-overlapping epitopes of the protein were used to ensure that our immunosignal was the consequence of a specific antigen–antibody interaction. When the immunoreactions for the Kv2.1 subunit were analysed at low magnification, strong immunolabelling of the SP and proximal part of the SR was observed (Fig. 3A–D), in line with the results of previous work (Trimmer, 1991; Maletic-Savatic et al., 1995; Du et al., 1998; Lim et al., 2000; Misonou et al., 2004; Rhodes & Trimmer, 2006). Interneurons in all CA1 layers also showed somato-dendritic labelling (Fig. 3A and D). High-magnification confocal microscopic images revealed plasma membrane-like labelling of somata, proximal apical and basal dendrites (Fig. 3E). Double-labelling experiments for Kv2.1 and Nav1.6 (Fig. 3E–K) revealed a clustered Kv2.1 labelling of AISs, confirming the results of Sarmiere et al. (2008). Interestingly, high-magnification single confocal images indicated that these Kv2.1-positive clusters did not overlap with the Nav1.6 containing parts of AISs (Fig. 3K).


Distinct axo-somato-dendritic distributions of three potassium channels in CA1 hippocampal pyramidal cells.

Kirizs T, Kerti-Szigeti K, Lorincz A, Nusser Z - Eur. J. Neurosci. (2014)

Immunofluorescent localisation of the Kv2.1 subunit in the CA1 region of the rat hippocampus. (A–C) Low-magnification view of the CA1 area double-labelled for the Kv2.1 (A) and the Nav1.6 (B) subunits. (A and D) Identical immunofluorescent labelling pattern obtained with two antibodies recognising different, non-overlapping parts of the Kv2.1 subunit indicates that the immunoreaction is specific. Arrows point to the somata of interneurons. (E–G) High-magnification images from the SP demonstrate that the immunolabelling for the Kv2.1 subunit is associated with somatic and proximal dendritic plasma membranes of CA1 PCs, as well as with AISs intensely labelled for the Nav1.6 subunit. (I–K) Higher magnification views of the boxed areas in E–G show punctate, non-uniform labelling for the Kv2.1 subunit along the Nav1.6-immunopositive AIS. Scale bars, 100 μm (A–D), 10 μm (E–G), 5 μm (I–K).
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig03: Immunofluorescent localisation of the Kv2.1 subunit in the CA1 region of the rat hippocampus. (A–C) Low-magnification view of the CA1 area double-labelled for the Kv2.1 (A) and the Nav1.6 (B) subunits. (A and D) Identical immunofluorescent labelling pattern obtained with two antibodies recognising different, non-overlapping parts of the Kv2.1 subunit indicates that the immunoreaction is specific. Arrows point to the somata of interneurons. (E–G) High-magnification images from the SP demonstrate that the immunolabelling for the Kv2.1 subunit is associated with somatic and proximal dendritic plasma membranes of CA1 PCs, as well as with AISs intensely labelled for the Nav1.6 subunit. (I–K) Higher magnification views of the boxed areas in E–G show punctate, non-uniform labelling for the Kv2.1 subunit along the Nav1.6-immunopositive AIS. Scale bars, 100 μm (A–D), 10 μm (E–G), 5 μm (I–K).
Mentions: For immunofluorescent localisation of the Kv2.1 subunit in the CA1 area, two antibodies recognising non-overlapping epitopes of the protein were used to ensure that our immunosignal was the consequence of a specific antigen–antibody interaction. When the immunoreactions for the Kv2.1 subunit were analysed at low magnification, strong immunolabelling of the SP and proximal part of the SR was observed (Fig. 3A–D), in line with the results of previous work (Trimmer, 1991; Maletic-Savatic et al., 1995; Du et al., 1998; Lim et al., 2000; Misonou et al., 2004; Rhodes & Trimmer, 2006). Interneurons in all CA1 layers also showed somato-dendritic labelling (Fig. 3A and D). High-magnification confocal microscopic images revealed plasma membrane-like labelling of somata, proximal apical and basal dendrites (Fig. 3E). Double-labelling experiments for Kv2.1 and Nav1.6 (Fig. 3E–K) revealed a clustered Kv2.1 labelling of AISs, confirming the results of Sarmiere et al. (2008). Interestingly, high-magnification single confocal images indicated that these Kv2.1-positive clusters did not overlap with the Nav1.6 containing parts of AISs (Fig. 3K).

Bottom Line: The Kv2.1 subunit was found in somatic, proximal dendritic and AIS plasma membranes at approximately the same densities.A quasi-linear increase in the Kir3.2 subunit density along the dendrites of PCs was detected, showing no significant difference between apical dendritic shafts, oblique dendrites or dendritic spines at the same distance from the soma.Our results demonstrate that each subunit has a unique cell-surface distribution pattern, and predict their differential involvement in synaptic integration and output generation at distinct subcellular compartments.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony Street 43, Budapest, Hungary.

Show MeSH
Related in: MedlinePlus