The mechanism of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor desensitization after removal of glutamate

Biophys J. 1995 Jan;68(1):137-46. doi: 10.1016/S0006-3495(95)80168-2.


We have examined responses of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate) receptors in the chick nucleus magnocellularis to pairs of pulses of glutamate and determined the extent of desensitization and the rate of recovery. Receptors recovered from desensitization with a time constant of 16 ms, regardless of the concentration or duration of the conditioning pulse. Even with very brief conditioning pulses, evoking submaximal currents, desensitization occurred at a consistent rate after the removal of free ligand. A quantitative kinetic model based on these data shows that receptors must desensitize from a closed state. The results provide evidence that very brief exposure to glutamate, on the time scale of uniquantal synaptic transmission, will result in a significant reduction in sensitivity of postsynaptic receptors.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biophysical Phenomena
  • Biophysics
  • Chick Embryo
  • Cochlear Nucleus / cytology
  • Cochlear Nucleus / drug effects
  • Cochlear Nucleus / metabolism
  • Glutamic Acid / pharmacology*
  • In Vitro Techniques
  • Kainic Acid / pharmacology
  • Kinetics
  • Models, Neurological
  • Neurons / drug effects
  • Neurons / metabolism
  • Receptors, AMPA / drug effects*
  • Receptors, AMPA / metabolism


  • Receptors, AMPA
  • Glutamic Acid
  • Kainic Acid