title: Polarized and compartment-dependent distribution of HCN1 in pyramidal cell dendrites.
abstract: An ion channel's function depends largely on its location and density on neurons. Here we used high-resolution immunolocalization to determine the subcellular distribution of the hyperpolarization-activated and cyclic-nucleotide-gated channel subunit 1 (HCN1) in rat brain. Light microscopy revealed graded HCN1 immunoreactivity in apical dendrites of hippocampal, subicular and neocortical layer-5 pyramidal cells. Quantitative comparison of immunogold densities showed a 60-fold increase from somatic to distal apical dendritic membranes. Distal dendritic shafts had 16 times more HCN1 labeling than proximal dendrites of similar diameters. At the same distance from the soma, the density of HCN1 was significantly higher in dendritic shafts than in spines. Our results reveal the complex cell surface distribution of voltage-gated ion-channels, and predict its role in increasing the computational power of single neurons via subcellular domain and input-specific mechanisms.
authors.affiliation: Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Szigony Street 43, 1083 Budapest, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lörincz
authors.forename: Takuya
authors.initials: T
authors.lastname: Notomi
authors.forename: Gábor
authors.initials: G
authors.lastname: Tamás
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Shigemoto
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Nusser
mesh_terms: D000818:Animals; D002451:Cell Compartmentation / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D054815:Cyclic Nucleotide-Gated Cation Channels; D003712:Dendrites / Q000737:chemistry* / Q000648:ultrastructure; D006168:Guinea Pigs; D006624:Hippocampus / Q000166:cytology; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D007150:Immunohistochemistry; D007473:Ion Channels / Q000032:analysis*; D008297:Male; D016253:Microscopy, Immunoelectron; D019579:Neocortex / Q000166:cytology; D015221:Potassium Channels; D017966:Pyramidal Cells / Q000737:chemistry* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; C578667:Hcn1 protein, rat; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D007473:Ion Channels; D015221:Potassium Channels