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: Because the Kir3.2 subunit forms homomeric channels and seems to be an essential component of heteromeric Kir3 channels (Liao et al., 1996), we performed SDS-FRL of this subunit and addressed whether and how its dendritic density changes as a function of distance from the soma. High-resolution EM images revealed only very few gold particles for the Kir3.2 subunit on the P-face membranes (epitope 374–414 is cytoplasmic) of somata and proximal apical dendrites (Fig. 7A–C). In comparison, more gold particles were observed on apical dendrites in distal SR and SLM (Fig. 7D–G). In SR, spiny oblique dendrites and dendritic spines were also moderately labelled (Fig. 7H and I).
Affiliation: Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony Street 43, Budapest, Hungary.