Skip to main content

Main menu

  • HOME
  • CONTENT
    • Early Release
    • Featured
    • Current Issue
    • Issue Archive
    • Collections
    • Podcast
  • ALERTS
  • FOR AUTHORS
    • Information for Authors
    • Fees
    • Journal Clubs
    • eLetters
    • Submit
  • EDITORIAL BOARD
  • ABOUT
    • Overview
    • Advertise
    • For the Media
    • Rights and Permissions
    • Privacy Policy
    • Feedback
  • SUBSCRIBE

User menu

  • Log in
  • My Cart

Search

  • Advanced search
Journal of Neuroscience
  • Log in
  • My Cart
Journal of Neuroscience

Advanced Search

Submit a Manuscript
  • HOME
  • CONTENT
    • Early Release
    • Featured
    • Current Issue
    • Issue Archive
    • Collections
    • Podcast
  • ALERTS
  • FOR AUTHORS
    • Information for Authors
    • Fees
    • Journal Clubs
    • eLetters
    • Submit
  • EDITORIAL BOARD
  • ABOUT
    • Overview
    • Advertise
    • For the Media
    • Rights and Permissions
    • Privacy Policy
    • Feedback
  • SUBSCRIBE
PreviousNext
Articles

Stepwise repolarization from Ca2+ plateaus in neocortical pyramidal cells: evidence for nonhomogeneous distribution of HVA Ca2+ channels in dendrites

I Reuveni, A Friedman, Y Amitai and MJ Gutnick
Journal of Neuroscience 1 November 1993, 13 (11) 4609-4621; DOI: https://doi.org/10.1523/JNEUROSCI.13-11-04609.1993
I Reuveni
Department of Physiology, Corob Center for Medical Research, Faculty of Health Sciences, Ben Gurion University of the Negev, Beersheva, Israel.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
A Friedman
Department of Physiology, Corob Center for Medical Research, Faculty of Health Sciences, Ben Gurion University of the Negev, Beersheva, Israel.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Y Amitai
Department of Physiology, Corob Center for Medical Research, Faculty of Health Sciences, Ben Gurion University of the Negev, Beersheva, Israel.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
MJ Gutnick
Department of Physiology, Corob Center for Medical Research, Faculty of Health Sciences, Ben Gurion University of the Negev, Beersheva, Israel.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Info & Metrics
  • eLetters
  • PDF
Loading

Abstract

Although cortical dendrites have classically been thought of as passive structures, recent evidence suggests that active conductances, including Ca2+ conductance, are also present in the dendritic membrane. To investigate this, we have recorded intracellularly in slices of rat neocortex bathed in 24 mM tetraethylammonium chloride and 1 microM TTX. Under these conditions, pyramidal neurons generated prolonged Ca2+ spikes. In computer simulations, the breakpoint voltage from which the plateau level began to repolarize was closely related to a specific region on the voltage/activation curve of the high-voltage-activated Ca2+ conductance underlying the spike. This modeling result was supported by the experimental observation that substituting Ba2+ for Ca2+ caused a hyperpolarizing shift in breakpoint voltage by 8–10 mV. Often there was stepwise repolarization from the Ca2+ spike to one or more additional plateau levels. In compartmental computer models, this could be simulated by two different mechanisms: (1) the presence of multiple, electrotonically separated sites of Ca2+ spike electrogenesis in the dendritic tree, and (2) the presence of Ca2+ channels with different voltage dependencies in the same compartment. In experiments, brief hyperpolarizing pulses could cut short the high-amplitude plateau without terminating the smaller “steps.” This result could be simulated by both computer models. However, only the multicompartmental model could simulate effects of prolonged depolarizing and hyperpolarizing currents on the breakpoint. Thus, the more depolarized the breakpoint, and hence the closer the spike initiation zone to the recording site, the less it was affected by the injected current. In experiments, the ratio of the breakpoint voltages for the different plateau levels was equal to the ratio of the highest repolarization rates. These data indicate that the breakpoint voltage and the time course of repolarization were the same at all the sites of Ca2+ electrogenesis. Our findings provide strong evidence that Ca2+ spike initiation occurs at electrotonically separated “hot spots” in the dendrites, and that voltage dependence of the Ca2+ channels that underlie the spikes is the same at all sites.

Back to top

In this issue

The Journal of Neuroscience: 13 (11)
Journal of Neuroscience
Vol. 13, Issue 11
1 Nov 1993
  • Table of Contents
  • Table of Contents (PDF)
  • Index by author
Email

Thank you for sharing this Journal of Neuroscience article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Stepwise repolarization from Ca2+ plateaus in neocortical pyramidal cells: evidence for nonhomogeneous distribution of HVA Ca2+ channels in dendrites
(Your Name) has forwarded a page to you from Journal of Neuroscience
(Your Name) thought you would be interested in this article in Journal of Neuroscience.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
View Full Page PDF
Citation Tools
Stepwise repolarization from Ca2+ plateaus in neocortical pyramidal cells: evidence for nonhomogeneous distribution of HVA Ca2+ channels in dendrites
I Reuveni, A Friedman, Y Amitai, MJ Gutnick
Journal of Neuroscience 1 November 1993, 13 (11) 4609-4621; DOI: 10.1523/JNEUROSCI.13-11-04609.1993

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Respond to this article
Request Permissions
Share
Stepwise repolarization from Ca2+ plateaus in neocortical pyramidal cells: evidence for nonhomogeneous distribution of HVA Ca2+ channels in dendrites
I Reuveni, A Friedman, Y Amitai, MJ Gutnick
Journal of Neuroscience 1 November 1993, 13 (11) 4609-4621; DOI: 10.1523/JNEUROSCI.13-11-04609.1993
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
  • Info & Metrics
  • eLetters
  • PDF

Responses to this article

Respond to this article

Jump to comment:

No eLetters have been published for this article.

Related Articles

Cited By...

More in this TOC Section

  • Choice Behavior Guided by Learned, But Not Innate, Taste Aversion Recruits the Orbitofrontal Cortex
  • Maturation of Spontaneous Firing Properties after Hearing Onset in Rat Auditory Nerve Fibers: Spontaneous Rates, Refractoriness, and Interfiber Correlations
  • Insulin Treatment Prevents Neuroinflammation and Neuronal Injury with Restored Neurobehavioral Function in Models of HIV/AIDS Neurodegeneration
Show more Articles
  • Home
  • Alerts
  • Visit Society for Neuroscience on Facebook
  • Follow Society for Neuroscience on Twitter
  • Follow Society for Neuroscience on LinkedIn
  • Visit Society for Neuroscience on Youtube
  • Follow our RSS feeds

Content

  • Early Release
  • Current Issue
  • Issue Archive
  • Collections

Information

  • For Authors
  • For Advertisers
  • For the Media
  • For Subscribers

About

  • About the Journal
  • Editorial Board
  • Privacy Policy
  • Contact
(JNeurosci logo)
(SfN logo)

Copyright © 2023 by the Society for Neuroscience.
JNeurosci Online ISSN: 1529-2401

The ideas and opinions expressed in JNeurosci do not necessarily reflect those of SfN or the JNeurosci Editorial Board. Publication of an advertisement or other product mention in JNeurosci should not be construed as an endorsement of the manufacturer’s claims. SfN does not assume any responsibility for any injury and/or damage to persons or property arising from or related to any use of any material contained in JNeurosci.