Modulation of septal cell activity by extracellular zinc. Academic Article uri icon

Overview

abstract

  • Zinc released from axon terminals in the brain can interact with multiple membrane channels and receptors. However, the specific effects of these Zn(2+)-dependent interactions on physiological processes remains unclear. Because Zn(2+)-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 (> or = 83%) Na+ and Ca2+ currents were blocked with 1 microM tetrodotoxin (TTX) and 2 mM Co2+, action potentials persisted after either 1 microM TTX or 2 mM Co2+ application. In contrast, concentrations of Zn2+ (50-300 microM) that induced incomplete blockade (< or = 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.

publication date

  • September 29, 1997

Research

keywords

  • Septum Pellucidum
  • Zinc

Identity

Scopus Document Identifier

  • 0030793716

Digital Object Identifier (DOI)

  • 10.1097/00001756-199709290-00015

PubMed ID

  • 9331918

Additional Document Info

volume

  • 8

issue

  • 14