Alpha-latrotoxin channels in neuroblastoma cells

J Membr Biol. 1994 Feb;138(1):91-102. doi: 10.1007/BF00211072.

Abstract

The changes in ionic permeability induced by the application of alpha-latrotoxin to NG108-15 neuroblastoma x glioma cells were examined using the nystatin perforated-patch technique for whole-cell recording. Complex single channel activity appeared in the plasmalemmas after delays that ranged from 1-20 min in Krebs' solution. The conductance of a channel fluctuated among at least three broad, approximately equispaced bands, the maximum conductance being about 300 pS, and the reversal potential approximately 0 mV. The channels were permeable to Na+, K+, Ca2+ and Mg2+, poorly permeable to glucosamineH+ and Cl-, and were blocked by La3+. The channels stayed fully open in Ca(2+)-free solutions with 4 mM Mg2+, in solutions with no divalent cations and in solutions with 2 mM Ca2+ and 96 mM Mg2+. They opened infrequently if both internal and external Cl- were replaced by glutamate-. If alpha-latrotoxin opened similar channels in nerve terminals, the flux of ions through them could account for the massive release of neurotransmitter induced by the toxin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Black Widow Spider
  • Calcium / physiology
  • Cell Membrane Permeability / drug effects
  • Ion Channels / drug effects*
  • Lanthanum / pharmacology
  • Membrane Potentials / drug effects
  • Receptors, Peptide / physiology
  • Solutions
  • Spider Venoms / pharmacology*
  • Tumor Cells, Cultured

Substances

  • Ion Channels
  • Receptors, Peptide
  • Solutions
  • Spider Venoms
  • alpha-latrotoxin receptor
  • alpha-latrotoxin
  • Lanthanum
  • Calcium

Grant support