Distinct axo-somato-dendritic distributions of three potassium channels in CA1 hippocampal pyramidal cells.
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.
Affiliation: Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony Street 43, Budapest, Hungary.Show MeSH
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Mentions: First, we investigated the distribution of the Kv1.1 subunit in the CA1 area of the hippocampus using LM immunofluorescent localisations with two antibodies directed against different, non-overlapping parts of the Kv1.1 protein (see Materials and methods) and found identical labelling (Fig. 1A–D). At low magnifications, an intense punctate neuropil labelling was seen in the SO and SR in agreement with published data (Veh et al., 1995; Rhodes et al., 1997; Monaghan et al., 2001; Lorincz & Nusser, 2008a), corresponding to either presynaptic terminals (Monaghan et al., 2001) or dendritic spines. At higher magnifications, AISs (Fig. 1E–G) and the juxta-paranodal region of myelinated axons were also observed. In order to unequivocally identify the origin of the punctate neuropil labelling of the SO and SR, and to assess the densities of the Kv1.1 subunit in 18 axo-somato-dendritic compartments of CA1 PCs, we turned to SDS-FRL.
Affiliation: Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony Street 43, Budapest, Hungary.