J Physiol Society Meetings
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Physiol Volume 521, Number 3, 629-636, December 15, 1999
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Magistretti, J.
Right arrow Articles by Alonso, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Magistretti, J.
Right arrow Articles by Alonso, A.
The Journal of Physiology (1999), 521.3, pp. 629-636
© Copyright 1999 The Physiological Society

Direct demonstration of persistent Na+ channel activity in dendritic processes of mammalian cortical neurones

Jacopo Magistretti *¹, David S. Ragsdale * and Angel Alonso *

* Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Québec, Canada H3A 2B4 and ¹ Laboratorio di Biofisica e Neurofisiologia dei Sistemi Corticali, Dipartimento di Neurofisiologia Sperimentale, Istituto Nazionale Neurologico 'Carlo Besta', Via Celoria 11, 20133 Milano, Italy

  1. Single Na+ channel activity was recorded in patch-clamp, cell-attached experiments performed on dendritic processes of acutely isolated principal neurones from rat entorhinal-cortex layer II. The distances of the recording sites from the soma ranged from ~20 to ~100 µm.

  2. Step depolarisations from holding potentials of -120 to -100 mV to test potentials of -60 to +10 mV elicited Na+ channel openings in all of the recorded patches (n = 16).

  3. In 10 patches, besides transient Na+ channel openings clustered within the first few milliseconds of the depolarising pulses, prolonged and/or late Na+ channel openings were also regularly observed. This 'persistent' Na+ channel activity produced net inward, persistent currents in ensemble-average traces, and remained stable over the entire duration of the experiments (~9 to 30 min).

  4. Two of these patches contained <= 3 channels. In these cases, persistent Na+ channel openings could be attributed to the activity of one single channel.

  5. The voltage dependence of persistent-current amplitude in ensemble-average traces closely resembled that of whole-cell, persistent Na+ current expressed by the same neurones, and displayed the same characteristic low threshold of activation.

  6. Dendritic, persistent Na+ channel openings had relatively high single-channel conductance (~20 pS), similar to what is observed for somatic, persistent Na+ channels.

  7. We conclude that a stable, persistent Na+ channel activity is expressed by proximal dendrites of entorhinal-cortex layer II principal neurones, and can contribute a significant low-threshold, persistent Na+ current to the dendritic processing of excitatory synaptic inputs.



This article has been cited by other articles:


Home page
 Neural Comput.Home page
G. Gradwohl and Y. Grossman
Analysis of the interaction between the dendritic conductance density and activated area in modulating alpha-motoneuron EPSP: statistical computer model.
Neural Comput., June 1, 2008; 20(6): 1385 - 1410.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
J. A. Rosenkranz and D. Johnston
State-Dependent Modulation of Amygdala Inputs by Dopamine-Induced Enhancement of Sodium Currents in Layer V Entorhinal Cortex
J. Neurosci., June 27, 2007; 27(26): 7054 - 7069.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
E. Shirahata, H. Iwasaki, M. Takagi, C. Lin, V. Bennett, Y. Okamura, and K. Hayasaka
Ankyrin-G Regulates Inactivation Gating of the Neuronal Sodium Channel, Nav1.6
J Neurophysiol, September 1, 2006; 96(3): 1347 - 1357.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
N. Astman, M. J. Gutnick, and I. A. Fleidervish
Persistent sodium current in layer 5 neocortical neurons is primarily generated in the proximal axon.
J. Neurosci., March 29, 2006; 26(13): 3465 - 3473.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
E. A. Tolner, F. Kloosterman, E. A. van Vliet, M. P. Witter, F. H. L. da Silva, and J. A. Gorter
Presubiculum Stimulation In Vivo Evokes Distinct Oscillations in Superficial and Deep Entorhinal Cortex Layers in Chronic Epileptic Rats
J. Neurosci., September 21, 2005; 25(38): 8755 - 8765.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
J. Magistretti, D. S. Ragsdale, and A. Alonso
Kinetic Diversity of Single-Channel Burst Openings Underlying Persistent Na+ Current in Entorhinal Cortex Neurons
Biophys. J., November 1, 2003; 85(5): 3019 - 3034.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
B. Doiron, L. Noonan, N. Lemon, and R. W. Turner
Persistent Na+ Current Modifies Burst Discharge By Regulating Conditional Backpropagation of Dendritic Spikes
J Neurophysiol, January 1, 2003; 89(1): 324 - 337.
[Abstract] [Full Text] [PDF]

Home page
 J. Gen. Physiol.Home page
J. Magistretti and A. Alonso
Fine Gating Properties of Channels Responsible for Persistent Sodium Current Generation in Entorhinal Cortex Neurons
J. Gen. Physiol., November 25, 2002; 120(6): 855 - 873.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
I. M. Raman, A. E. Gustafson, and D. Padgett
Ionic Currents and Spontaneous Firing in Neurons Isolated from the Cerebellar Nuclei
J. Neurosci., December 15, 2000; 20(24): 9004 - 9016.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1999 The Physiological Society.