I(h) 'run-up' in rat neocortical neurons and transiently rat or human HCN1-expressing HEK293 cells
| Autor: | Arne Battefeld, Tanja Velmans, Ying C. Li, Lennart Barthel, Claudia Bierwirth, Ulf Strauss |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Patch-Clamp Techniques
Potassium Channels Time Factors GTP' Voltage clamp Medizin Cyclic Nucleotide-Gated Cation Channels Neocortex Phosphocreatine Membrane Potentials Cellular and Molecular Neuroscience chemistry.chemical_compound Cytosol Organ Culture Techniques Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels Animals Humans Patch clamp Phosphorylation Rats Wistar Ion channel Membrane potential Neurons Cell Polarity Depolarization Potassium channel Rats HEK293 Cells chemistry Biochemistry Biophysics Female Ion Channel Gating |
| Zdroj: | Journal of neuroscience research. 88(14) |
| ISSN: | 1097-4547 |
| Popis: | Hyperpolarization-activated cyclic nucleotide-gated ion channels (HCN) are key determinants of CNS functions. Here we describe an increase in hyperpolarization-activated current (I(h)) at the beginning of whole-cell recordings in rat layer 5 cortical neurons. For a closer investigation of this I(h) increase, we overexpressed the predominant layer 5 rat subunit HCN1 in HEK293 cells. We characterized the resulting I(h) in the cell-attached and whole-cell configurations. Breaking into whole-cell configuration led to about a 30% enhancement of rat HCN1-mediated I(h) accompanied by a depolarizing shift in voltage dependence and an accelerated time course of activation. This current enhancement is not species specific; for human HCN1, the current similarly increases in amount and kinetics. Although the changes were bound to cytosolic solution exchange, they were independent of cAMP, ATP, GTP, and the phosphate group donor phosphocreatine. Together, these data provide a characterization of heterologous expression of rat HCN1 and suggest that cytosolic contents suppress I(h). Such a mechanism might constitute a reserve in h-channel function in vivo. |
| Databáze: | OpenAIRE |
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