Modulation of glycine-induced currents by zinc and other metal cations in neurons acutely dissociated from the dorsal motor nucleus of the vagus of the rat

Brain Res. 1999 Jan 23;816(2):424-30. doi: 10.1016/s0006-8993(98)01172-x.


Effects of Zn2+ and other polyvalent cations on glycine-induced currents in the freshly dissociated rat dorsal motor nucleus of the vagus neurons were investigated under voltage-clamp conditions by the use of the nystatin-perforated patch recording configuration. Glycine evoked a Cl- current in a concentration-dependent manner with a half-maximum effective concentration (EC50) of 3.3x10-5 M. Strychnine inhibited the 3x10-5 M glycine-induced current in a concentration-dependent manner with a half-maximal inhibitory concentration (IC50) of 6.8x10-7 M. At low concentrations (3x10-8 M-3x10-6 M), Zn2+ potentiated the current elicited by 3x10-5 M glycine. On the other hand, at concentrations higher than 10-5 M, Zn2+ inhibited the glycine response. The biphasic action of Zn2+ was mimicked by Ni2+, but La3+ and Co2+ had only potentiating effect. Zn2+ shifted the concentration-response curve for the glycine-induced current without changing the maximum response, and the EC50 values for the glycine response in the absence and presence of 10-6 M and 10-4 M Zn2+ were 3.3x10-5 M, 1.3x10-5 M and 1.3x10-4 M, respectively. These results suggest that the biphasic modulation of glycine response by Zn2+ results from changes in apparent glycine affinity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cations / pharmacology*
  • Chloride Channels / drug effects
  • Glycine / pharmacology*
  • Membrane Potentials / drug effects
  • Motor Neurons / drug effects*
  • Neurons / drug effects*
  • Patch-Clamp Techniques
  • Rats
  • Rats, Wistar
  • Vagus Nerve / drug effects*
  • Zinc / pharmacology*


  • Cations
  • Chloride Channels
  • Zinc
  • Glycine