Zinc modulation of a transient potassium current and histochemical localization of the metal in neurons of the suprachiasmatic nucleus

Rong Chi Huang, You Wei Peng, King-Wai Yau

Research output: Contribution to journalArticle

Abstract

The effect of Zn2+ on a voltage-dependent, transient potassium current (IA) in acutely dissociated neurons from the suprachiasmatic nucleus was studied with the whole-cell patch-clamp technique. At micromolar concentrations, Zn2+ markedly potentiated IA activated from a holding potential of -60 mV, which is the resting potential of these neurons. This potentiation occurred at a Zn2+ concentration as low as 2 μM and increased with higher Zn2+ concentrations. The Zn2+ action appears to arise from a shift in the steady-state inactivation of IA to more positive voltages. At 30 μM, Zn2+ shifted the half-inactivation voltage by +20 mV (from -80 mV to -60 mV), and 200 μM Zn2+ shifted this voltage by +45 mV (from -80 mV to -35 mV). Histochemically, we have also observed Zn2+ staining throughout the suprachiasmatic nucleus; the staining is particularly intense in the ventrolateral region of the nucleus, which receives the major fiber inputs. Our findings suggest that Zn2+, presumably synaptically released, may modulate the electrical activity of suprachiasmatic nucleus neurons through IA. Because vesicular Zn2+ is fairly widespread in the central nervous system, it is conceivable that this kind of Zn2+ modulation on IA, and possibly on other voltage-activated currents, exists elsewhere in the brain.

Original languageEnglish (US)
Pages (from-to)11806-11810
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number24
StatePublished - Dec 15 1993

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Suprachiasmatic Nucleus
Zinc
Potassium
Metals
Neurons
Staining and Labeling
Patch-Clamp Techniques
Membrane Potentials
Central Nervous System
Brain

ASJC Scopus subject areas

  • General
  • Genetics

Cite this

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title = "Zinc modulation of a transient potassium current and histochemical localization of the metal in neurons of the suprachiasmatic nucleus",
abstract = "The effect of Zn2+ on a voltage-dependent, transient potassium current (IA) in acutely dissociated neurons from the suprachiasmatic nucleus was studied with the whole-cell patch-clamp technique. At micromolar concentrations, Zn2+ markedly potentiated IA activated from a holding potential of -60 mV, which is the resting potential of these neurons. This potentiation occurred at a Zn2+ concentration as low as 2 μM and increased with higher Zn2+ concentrations. The Zn2+ action appears to arise from a shift in the steady-state inactivation of IA to more positive voltages. At 30 μM, Zn2+ shifted the half-inactivation voltage by +20 mV (from -80 mV to -60 mV), and 200 μM Zn2+ shifted this voltage by +45 mV (from -80 mV to -35 mV). Histochemically, we have also observed Zn2+ staining throughout the suprachiasmatic nucleus; the staining is particularly intense in the ventrolateral region of the nucleus, which receives the major fiber inputs. Our findings suggest that Zn2+, presumably synaptically released, may modulate the electrical activity of suprachiasmatic nucleus neurons through IA. Because vesicular Zn2+ is fairly widespread in the central nervous system, it is conceivable that this kind of Zn2+ modulation on IA, and possibly on other voltage-activated currents, exists elsewhere in the brain.",
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AU - Yau, King-Wai

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AB - The effect of Zn2+ on a voltage-dependent, transient potassium current (IA) in acutely dissociated neurons from the suprachiasmatic nucleus was studied with the whole-cell patch-clamp technique. At micromolar concentrations, Zn2+ markedly potentiated IA activated from a holding potential of -60 mV, which is the resting potential of these neurons. This potentiation occurred at a Zn2+ concentration as low as 2 μM and increased with higher Zn2+ concentrations. The Zn2+ action appears to arise from a shift in the steady-state inactivation of IA to more positive voltages. At 30 μM, Zn2+ shifted the half-inactivation voltage by +20 mV (from -80 mV to -60 mV), and 200 μM Zn2+ shifted this voltage by +45 mV (from -80 mV to -35 mV). Histochemically, we have also observed Zn2+ staining throughout the suprachiasmatic nucleus; the staining is particularly intense in the ventrolateral region of the nucleus, which receives the major fiber inputs. Our findings suggest that Zn2+, presumably synaptically released, may modulate the electrical activity of suprachiasmatic nucleus neurons through IA. Because vesicular Zn2+ is fairly widespread in the central nervous system, it is conceivable that this kind of Zn2+ modulation on IA, and possibly on other voltage-activated currents, exists elsewhere in the brain.

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