Modulation of septal cell activity by extracellular zinc

Luis V. Colom, Alan Neely, Maria E. Diaz, Wen Jie Xie, Stanley H. Appel

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

ZINC released from axon terminals in the brain can interact with multiple membrane channels and receptors. However, the specific effects of these Zn2+dependent interactions on physiological processes remains unclear. Because Zn2+ -containing axon terminals are abundant in the septal region, we selected a septal cell line (SN56) to study the effects of Zn2+ on cell activity. Voltage-clamp recordings showed well-developed voltage- dependent Na+, Ca2+ and K+ currents. Micromolar concentrations of Zn2+ partially blocked Na+ and Ca2+ currents without affecting K+ currents. Current-clamp recordings showed that SN56 cells fire spontaneous and evoked action potentials. While most (≤83%) Na+ and Ca2+ currents were blocked with 1 μM tetrodotoxin (TTX) and 2 mM Co2+, action potentials persisted after either 1 μM TTX or 2 mM Co2+ application. In contrast, concentrations of Zn2+ (50-300 μM) that induced incomplete blockade (≤ 50%) of either Ca2+ and Na+ currents abolished action potential generation. These data show that simultaneous and partial blockade of Ca2+ and Na+ channels by Zn2+ inhibit SN56 cell activity. Because septal outputs extensively modulate the excitability of cortical and subcortical brain regions, Zn2+ inhibition of action potential generation in septal neurons could play an important physiological role in regulating brain activity.

Original languageEnglish (US)
Pages (from-to)3081-3086
Number of pages6
JournalNeuroReport
Volume8
Issue number14
DOIs
StatePublished - Jan 1 1997

Keywords

  • Ca channel
  • Na channel
  • Septum
  • Zinc

ASJC Scopus subject areas

  • Neuroscience(all)

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