title: Hyperpolarization-activated cyclic-nucleotide gated 4 (HCN4) protein is expressed in a subset of rat dorsal root and trigeminal ganglion neurons.
abstract: Hyperpolarization-activated cyclic nucleotide-gated (HCN) cation channels are active at resting membrane potential and thus are likely to contribute to neuronal excitability. Four HCN channel subunits (HCN1-4) have previously been cloned. The aim of the current study was to investigate the immunoreactivity of HCN4 channel protein in rat trigeminal (TG) and dorsal root ganglion (DRG) sensory neurons. HCN4 was present in 9% of TG neurons and 4.7% of DRG neurons, it was distributed in a discrete population of small-diameter neurons in the TG but was located in cells of all sizes in the DRG. Approximately two thirds of HCN4-containing neurons in each ganglia were labelled with antisera raised against the 200-kDa neurofilament (NF200). The remaining HCN4-containing neurons were NF200-negative, were not labelled with antisera raised against calcitonin-gene related peptide (CGRP), and did not bind the isolectin B4 (IB4). HCN4-containing neurons made up more than half of the population of small-diameter primary afferent neurons that did not contain either NF200 or CGRP or bind IB4 in both TG and DRG. This population was not insignificant, comprising 5% of TG neurons and 2% of DRG neurons.
authors.affiliation: Department Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: Hyun-jung
authors.initials: HJ
authors.lastname: Cho
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Staikopoulos
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Ivanusic
authors.forename: Ernest A
authors.initials: EA
authors.lastname: Jennings
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D015740:Calcitonin Gene-Related Peptide / Q000276:immunology / Q000378:metabolism; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000276:immunology / Q000378:metabolism; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D037102:Lectins / Q000378:metabolism; D016900:Neurofilament Proteins / Q000276:immunology / Q000378:metabolism; D015221:Potassium Channels / Q000096:biosynthesis* / Q000276:immunology; D051381:Rats; D011984:Sensory Receptor Cells / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism*
chemical_list: D000906:Antibodies; D054815:Cyclic Nucleotide-Gated Cation Channels; C513836:HCN4 protein, rat; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D037102:Lectins; D016900:Neurofilament Proteins; D015221:Potassium Channels; C051774:neurofilament protein H; D015740:Calcitonin Gene-Related Peptide