Zinc (Zn2+) blocks voltage gated calcium channels in cultured rat dorsal root ganglion cells. Academic Article uri icon

Overview

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 upon 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 microM 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 microM 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.

publication date

  • October 9, 1992

Research

keywords

  • Calcium Channels
  • Ganglia, Spinal
  • Ion Channel Gating
  • Neurons
  • Zinc

Identity

Scopus Document Identifier

  • 0026615796

Digital Object Identifier (DOI)

  • 10.1016/0006-8993(92)91266-h

PubMed ID

  • 1333873

Additional Document Info

volume

  • 593

issue

  • 1