Redistribution of K+ channels into dendrites is unlikely to account for developmental down regulation of A-currents in rat dentate gyrus granule cells.
The electrical reactions of many central neurons depend on two voltage-activated K+ currents: the fast transient A-current IA and the delayed rectifier current IK. In rat dentate gyrus granule cells, the A-current density decreases during ontogenesis, possibly due to a redistribution of K+ channels from somata into dendrites. We tested this possibility in mechanically isolated granule cells with preserved dendrites of different length. Potassium currents were recorded with the whole-cell patch-clamp technique using prepulse protocols with and without a delay interval to isolate IA. A correlation between the length of the dendrites and the amount of A-current expressed in a given cell could not be demonstrated. Our findings therefore confirm an ontogenetic down regulation of A-currents.
Strecker
T
T
Institut für Neurophysiologie, Zentrum für Physiologie und Pathophysiologie, Universität zu Köln, FRG.
Heinemann
U
U
D000818:Animals; D003712:Dendrites / Q000502:physiology*; D015536:Down-Regulation / Q000502:physiology*; D004594:Electrophysiology; D006624:Hippocampus / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D015221:Potassium Channels / Q000502:physiology*; D011712:Pyramidal Tracts / Q000254:growth & development / Q000502:physiology; D051381:Rats
D007473:Ion Channels; D015221:Potassium Channels