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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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High-resolution immunogold localisation of the Kv1.1 subunit in the CA1 area. (A) A large number of gold particles labelling the Kv1.1 subunit is observed on the P-face of an AIS. (B) Image of an AIS co-labelled for the Kv1.1 subunit (10-nm gold) and the AIS marker pan-NF (15-nm gold). (C and D) High-magnification views of the boxed regions shown in A and B. Note that both the Kv1.1 subunit (10-nm gold) and pan-NF (15-nm gold) are excluded from the PSD of an axoaxonic synapse. (E) Gold particles labelling the Kv1.1 subunit are present on the P-face of a myelinated axon in the alveus. (F) The P-face of an excitatory axon terminal (AxTerm) innervating a putative spine is labelled for the Kv1.1 subunit (arrows). The PSD of the synapse is indicated by the accumulation of IMPs on the postsynaptic E-face. (G) A SNAP-25 (15-nm gold)-immunopositive AxTerm, facing the PSD on the E-face of a spine (Sp), contains few gold particles for the Kv1.1 subunit (arrows; 10-nm gold). (H) Bar graphs illustrate Kv1.1 subunit densities (mean ± SD) in different axo-somato-dendritic compartments. *Significant differences from background (BG). Note that the AISs and the AxTerm in the SO and the proximal (prox.) and middle (mid.) parts of the SR contain significantly greater numbers of gold particles compared to background (anova, P < 0.001; Dunnett's post hoc test, P < 0.05; n = 3 rats). ApDendr, apical dendrite, OblDendr, oblique dendrite; Tuft Dendr, tuft dendrite. Scale bars, 500 nm (A and B); 250 nm (E–G); 100 nm (C and D).
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fig02: High-resolution immunogold localisation of the Kv1.1 subunit in the CA1 area. (A) A large number of gold particles labelling the Kv1.1 subunit is observed on the P-face of an AIS. (B) Image of an AIS co-labelled for the Kv1.1 subunit (10-nm gold) and the AIS marker pan-NF (15-nm gold). (C and D) High-magnification views of the boxed regions shown in A and B. Note that both the Kv1.1 subunit (10-nm gold) and pan-NF (15-nm gold) are excluded from the PSD of an axoaxonic synapse. (E) Gold particles labelling the Kv1.1 subunit are present on the P-face of a myelinated axon in the alveus. (F) The P-face of an excitatory axon terminal (AxTerm) innervating a putative spine is labelled for the Kv1.1 subunit (arrows). The PSD of the synapse is indicated by the accumulation of IMPs on the postsynaptic E-face. (G) A SNAP-25 (15-nm gold)-immunopositive AxTerm, facing the PSD on the E-face of a spine (Sp), contains few gold particles for the Kv1.1 subunit (arrows; 10-nm gold). (H) Bar graphs illustrate Kv1.1 subunit densities (mean ± SD) in different axo-somato-dendritic compartments. *Significant differences from background (BG). Note that the AISs and the AxTerm in the SO and the proximal (prox.) and middle (mid.) parts of the SR contain significantly greater numbers of gold particles compared to background (anova, P < 0.001; Dunnett's post hoc test, P < 0.05; n = 3 rats). ApDendr, apical dendrite, OblDendr, oblique dendrite; Tuft Dendr, tuft dendrite. Scale bars, 500 nm (A and B); 250 nm (E–G); 100 nm (C and D).

Mentions: Replicas were then incubated for 2 h in TBS containing 5% BSA and goat anti-rabbit IgGs coupled to 10- or 15-nm gold particles (1 : 100; British Biocell International Ltd., Cardiff, UK), or goat anti-mouse IgGs coupled to 10- or 15-nm gold particles (1 : 50 or 1 : 100; British Biocell). In most double-labelling reactions, a mixture of the two primary then a mixture of the two secondary antibodies was applied. However, we also performed sequential double-labelling reactions (e.g. for Kv1.1 and pan-NF as well as Kv1.1 and SNAP-25; see Fig. 2B and G, respectively) in which the anti-Kv1.1 primary antibody incubation was followed by the anti-rabbit secondary antibody incubation. After this the replicas were incubated with the anti-pan-NF or anti-SNAP-25 primary antibodies and then with the anti-mouse secondary antibodies. Finally, replicas were rinsed in TBS and distilled water before being picked up on copper parallel bar grids. Specimens were analysed with a transmission electron microscope (JEM-1011; JEOL Ltd., Tokyo, Japan).


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)

High-resolution immunogold localisation of the Kv1.1 subunit in the CA1 area. (A) A large number of gold particles labelling the Kv1.1 subunit is observed on the P-face of an AIS. (B) Image of an AIS co-labelled for the Kv1.1 subunit (10-nm gold) and the AIS marker pan-NF (15-nm gold). (C and D) High-magnification views of the boxed regions shown in A and B. Note that both the Kv1.1 subunit (10-nm gold) and pan-NF (15-nm gold) are excluded from the PSD of an axoaxonic synapse. (E) Gold particles labelling the Kv1.1 subunit are present on the P-face of a myelinated axon in the alveus. (F) The P-face of an excitatory axon terminal (AxTerm) innervating a putative spine is labelled for the Kv1.1 subunit (arrows). The PSD of the synapse is indicated by the accumulation of IMPs on the postsynaptic E-face. (G) A SNAP-25 (15-nm gold)-immunopositive AxTerm, facing the PSD on the E-face of a spine (Sp), contains few gold particles for the Kv1.1 subunit (arrows; 10-nm gold). (H) Bar graphs illustrate Kv1.1 subunit densities (mean ± SD) in different axo-somato-dendritic compartments. *Significant differences from background (BG). Note that the AISs and the AxTerm in the SO and the proximal (prox.) and middle (mid.) parts of the SR contain significantly greater numbers of gold particles compared to background (anova, P < 0.001; Dunnett's post hoc test, P < 0.05; n = 3 rats). ApDendr, apical dendrite, OblDendr, oblique dendrite; Tuft Dendr, tuft dendrite. Scale bars, 500 nm (A and B); 250 nm (E–G); 100 nm (C and D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4150533&req=5

fig02: High-resolution immunogold localisation of the Kv1.1 subunit in the CA1 area. (A) A large number of gold particles labelling the Kv1.1 subunit is observed on the P-face of an AIS. (B) Image of an AIS co-labelled for the Kv1.1 subunit (10-nm gold) and the AIS marker pan-NF (15-nm gold). (C and D) High-magnification views of the boxed regions shown in A and B. Note that both the Kv1.1 subunit (10-nm gold) and pan-NF (15-nm gold) are excluded from the PSD of an axoaxonic synapse. (E) Gold particles labelling the Kv1.1 subunit are present on the P-face of a myelinated axon in the alveus. (F) The P-face of an excitatory axon terminal (AxTerm) innervating a putative spine is labelled for the Kv1.1 subunit (arrows). The PSD of the synapse is indicated by the accumulation of IMPs on the postsynaptic E-face. (G) A SNAP-25 (15-nm gold)-immunopositive AxTerm, facing the PSD on the E-face of a spine (Sp), contains few gold particles for the Kv1.1 subunit (arrows; 10-nm gold). (H) Bar graphs illustrate Kv1.1 subunit densities (mean ± SD) in different axo-somato-dendritic compartments. *Significant differences from background (BG). Note that the AISs and the AxTerm in the SO and the proximal (prox.) and middle (mid.) parts of the SR contain significantly greater numbers of gold particles compared to background (anova, P < 0.001; Dunnett's post hoc test, P < 0.05; n = 3 rats). ApDendr, apical dendrite, OblDendr, oblique dendrite; Tuft Dendr, tuft dendrite. Scale bars, 500 nm (A and B); 250 nm (E–G); 100 nm (C and D).
Mentions: Replicas were then incubated for 2 h in TBS containing 5% BSA and goat anti-rabbit IgGs coupled to 10- or 15-nm gold particles (1 : 100; British Biocell International Ltd., Cardiff, UK), or goat anti-mouse IgGs coupled to 10- or 15-nm gold particles (1 : 50 or 1 : 100; British Biocell). In most double-labelling reactions, a mixture of the two primary then a mixture of the two secondary antibodies was applied. However, we also performed sequential double-labelling reactions (e.g. for Kv1.1 and pan-NF as well as Kv1.1 and SNAP-25; see Fig. 2B and G, respectively) in which the anti-Kv1.1 primary antibody incubation was followed by the anti-rabbit secondary antibody incubation. After this the replicas were incubated with the anti-pan-NF or anti-SNAP-25 primary antibodies and then with the anti-mouse secondary antibodies. Finally, replicas were rinsed in TBS and distilled water before being picked up on copper parallel bar grids. Specimens were analysed with a transmission electron microscope (JEM-1011; JEOL Ltd., Tokyo, Japan).

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