Differential blocking effects of the monoclonal anti-GQ1b IgM antibody and alpha-latrotoxin in the absence of complement at the mouse neuromuscular junction

Neurosci Lett. 2002 Dec 6;334(1):25-8. doi: 10.1016/s0304-3940(02)01037-6.


Numerous in vitro electrophysiological studies found different effects of anti-ganglioside antibodies on neuromuscular transmission. Since a complement-dependent, latrotoxin-like effect has been described for the mouse monoclonal anti-GQ1b IgM antibody (termed CGM3), we here investigated the effect of CGM3 and alpha-latrotoxin by means of the perfused macro-patch clamp electrode in mice hemidiaphragms in the absence of complement. The CGM3 mab depressed evoked quantal release dose-dependently, whereas the rate of spontaneous releases and the amplitude of postsynaptic currents was not significantly affected. Alpha-latrotoxin induced an increase in spontaneous releases followed by a blockade of evoked quantal release, this was not altered by CGM3. The complement-independent presynaptic block by CGM3 was different from the action of alpha-latrotoxin.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / analysis
  • Animals
  • Antibodies, Monoclonal / pharmacology*
  • Complement System Proteins
  • Diaphragm / drug effects
  • Diaphragm / physiology
  • Electrophysiology
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Gangliosides / antagonists & inhibitors
  • Gangliosides / immunology
  • Immunoglobulin M / immunology
  • Mice
  • Mice, Inbred BALB C
  • Neuromuscular Junction / drug effects*
  • Patch-Clamp Techniques
  • Spider Venoms / pharmacology


  • Antibodies, Monoclonal
  • Gangliosides
  • Immunoglobulin M
  • Spider Venoms
  • alpha-latrotoxin
  • GQ1b ganglioside
  • Complement System Proteins
  • Acetylcholine