Zinc (Zn2+) blocks voltage gated calcium channels in cultured rat dorsal root ganglion cells

Dietrich Büsselberg, Dagmar Michael, Martyn L. Evans, David O. Carpenter, Helmut L. Haas

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Abstract

Dorsal root ganglion cells (DRGs) exhibit 3 types of voltage-dependent calcium channels. We have cultured DRGs from 2- to 4-day-old rat pups and obtained whole-cell patch-clamp recordings of calcium-channel currents after 1-5 days in culture. The calcium-channel currents (carried by barium) were recorded with tetrodotoxin (TTX) in the external solution. A cesium-based solution containing Na-ATP, HEPES and EGTA was used in the recording pipette. Cells were held at -80 mV and calcium channel currents were evoked by stepping to depolarized voltages. The divalent cation zinc (Zn2+) blocked sustained and transient voltage sensitive calcium channel currents. Onset of the blockade was fast and a steady-state was reached within 5-15 min, depending upin the concentration used. The IC50 for inhibition of the peak current evoked by a step depolarization from -80 mV to 0 mV (N plus L channels) for 80 ms was 69 μM Zn2+ and the Hill slope about 1. The calcium current evoked by a voltage step from -80 mV to voltages between -40 mV and -15 mV (T-type current) was more sensitive (> 80% block with 20 μM Zn2+). During wash the effect was only partly reversible in 50% of the neurons. Thus, Zn2+ is a potent blocker of voltage dependent calcium currents in mammalian neurons, especially of T-type currents.

Original languageEnglish
Pages (from-to)77-81
Number of pages5
JournalBrain Research
Volume593
Issue number1
DOIs
Publication statusPublished - 9 Oct 1992

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Keywords

  • Calcium channel, Channel blockade
  • Dorsal root ganglion cell
  • Zinc

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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