Rapid activation and desensitization by glutamate of excitatory, cation-selective channels in locust muscle

Neurosci Lett. 1988 May 16;88(1):33-8. doi: 10.1016/0304-3940(88)90311-4.


Outside-out patches of membrane were excised from extensor tibiae muscles of locusts. L-Glutamate or its agonists were applied to such patches in short pulses by means of a lipid filament switch. Cationselective, excitatory channels were activated by quisqualate, L-glutamate and aspartate (in decreasing order of effectivity), but not by ibotenate, kainate, N-methyl-D-aspartate and glycine. At high agonist concentrations, channel activation reached a peak within 1 ms. Two kinetic types of channels have been identified: L-channels with on average relatively long and S-channels with short openings. Both types of channel openings showed surprisingly high rates of desensitization, channel activity declining after the initial surge to zero with time constants of about 25 and 3 ms, respectively. The L-channels exhibit open times close to those of channels recorded in M omega-seal studies. The S-channel has not been reported previously.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aspartic Acid / pharmacology
  • Cations
  • Glutamates / pharmacology*
  • Glutamic Acid
  • Grasshoppers
  • In Vitro Techniques
  • Ion Channels / drug effects
  • Ion Channels / physiology*
  • Membrane Potentials / drug effects
  • Muscles / drug effects
  • Muscles / physiology*
  • Oxadiazoles / pharmacology
  • Quisqualic Acid


  • Cations
  • Glutamates
  • Ion Channels
  • Oxadiazoles
  • Aspartic Acid
  • Glutamic Acid
  • Quisqualic Acid