| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
Voltage-dependent K+ channels in the apical dendrites of CA1 pyramidal neurones play important roles in regulating dendritic excitability, synaptic integration, and synaptic plasticity. Using cell-attached, voltage-clamp recordings, we found a large variability in the waveforms of macroscopic K+ currents in the dendrites. With single-channel analysis, however, we were able to identify four types of voltage-dependent K+ channels and we categorized them as belonging to delayed-rectifier, M-, D-, or A-type K+ channels previously described from whole-cell recordings. Delayed-rectifier-type K+ channels had a single-channel conductance of 19 ± 0.5 pS, and made up the majority of the sustained K+ current uniformly distributed along the apical dendrites. The M-type K+ channels had a single-channel conductance of 11 ± 0.8 pS, did not inactivate with prolonged membrane depolarization, deactivated with slow kinetics (time constant 100 ± 6 ms at –40 mV), and were inhibited by bath-applied muscarinic agonist carbachol (10 µM). The D-type K+ channels had a single-channel conductance of around 18 pS, and inactivated with a time constant of 98 ± 4 ms at +54 mV. The A-type K+ channels had a single-channel conductance of 6 ± 0.6 pS, inactivated with a time constant of 23 ± 2 ms at +54 mV, and contributed to the majority of the transient K+ current previously described. These results suggest both functional and molecular complexity for K+ channels in dendrites of CA1 pyramidal neurones.
(Received 13 May 2004;
accepted after revision 23 June 2004;
first published online 24 June 2004)
Corresponding author X. Chen: Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA. Email: xixi{at}ltp.neusc.bcm.tmc.edu
This article has been cited by other articles:
|
|
 |
|
  J. Maffie and B. Rudy Weighing the evidence for a ternary protein complex mediating A-type K+ currents in neurons J. Physiol., December 1, 2008; 586(23): 5609 - 5623. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. M. Shah, M. Migliore, I. Valencia, E. C. Cooper, and D. A. Brown Functional significance of axonal Kv7 channels in hippocampal pyramidal neurons PNAS, June 3, 2008; 105(22): 7869 - 7874. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. H. Brager and D. Johnston Plasticity of Intrinsic Excitability during Long-Term Depression Is Mediated through mGluR-Dependent Changes in Ih in Hippocampal CA1 Pyramidal Neurons J. Neurosci., December 19, 2007; 27(51): 13926 - 13937. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. D. Ellis, R. Krahe, C. W. Bourque, R. J. Dunn, and M. J. Chacron Muscarinic Receptors Control Frequency Tuning Through the Downregulation of an A-Type Potassium Current J Neurophysiol, September 1, 2007; 98(3): 1526 - 1537. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. E. Metz, N. Spruston, and M. Martina Dendritic D-type potassium currents inhibit the spike afterdepolarization in rat hippocampal CA1 pyramidal neurons J. Physiol., May 15, 2007; 581(1): 175 - 187. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Hu, K. Vervaeke, and J. F. Storm M-Channels (Kv7/KCNQ Channels) That Regulate Synaptic Integration, Excitability, and Spike Pattern of CA1 Pyramidal Cells Are Located in the Perisomatic Region J. Neurosci., February 21, 2007; 27(8): 1853 - 1867. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Chen, L.-L. Yuan, C. Zhao, S. G. Birnbaum, A. Frick, W. E. Jung, T. L. Schwarz, J. D. Sweatt, and D. Johnston Deletion of Kv4.2 Gene Eliminates Dendritic A-Type K+ Current and Enhances Induction of Long-Term Potentiation in Hippocampal CA1 Pyramidal Neurons. J. Neurosci., November 22, 2006; 26(47): 12143 - 12151. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. C. Rumsey and L. F. Abbott Synaptic Democracy in Active Dendrites J Neurophysiol, November 1, 2006; 96(5): 2307 - 2318. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Vervaeke, N. Gu, C. Agdestein, H. Hu, and J. F. Storm Kv7/KCNQ/M-channels in rat glutamatergic hippocampal axons and their role in regulation of excitability and transmitter release J. Physiol., October 1, 2006; 576(1): 235 - 256. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. J. Chung, Y. N. Jan, and L. Y. Jan Polarized axonal surface expression of neuronal KCNQ channels is mediated by multiple signals in the KCNQ2 and KCNQ3 C-terminal domains PNAS, June 6, 2006; 103(23): 8870 - 8875. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Yue and Y. Yaari Axo-Somatic and Apical Dendritic Kv7/M Channels Differentially Regulate the Intrinsic Excitability of Adult Rat CA1 Pyramidal Cells J Neurophysiol, June 1, 2006; 95(6): 3480 - 3495. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Guan, J. C. F. Lee, T. Tkatch, D. J. Surmeier, W. E. Armstrong, and R. C. Foehring Expression and biophysical properties of Kv1 channels in supragranular neocortical pyramidal neurones J. Physiol., March 1, 2006; 571(2): 371 - 389. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Migliore, M. Ferrante, and G. A. Ascoli Signal Propagation in Oblique Dendrites of CA1 Pyramidal Cells J Neurophysiol, December 1, 2005; 94(6): 4145 - 4155. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Chen and D. Johnston Constitutively Active G-Protein-Gated Inwardly Rectifying K+ Channels in Dendrites of Hippocampal CA1 Pyramidal Neurons J. Neurosci., April 13, 2005; 25(15): 3787 - 3792. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
