Analysis of a slow desensitized state of recombinant adult-type nicotinic acetylcholine receptor channels

Eur J Neurosci. 2002 Aug;16(4):652-8. doi: 10.1046/j.1460-9568.2002.02114.x.


A characteristic feature of the kinetics of nicotinic acetylcholine receptor (nAChR) channels is fast and nearly complete desensitization with a time course between 10 and 100 ms and recovery from desensitization in the range of some hundred ms. In the present study we used a piezo-driven system for ultra-fast solution exchange, analysed the recovery from the fast desensitized state of mouse recombinant adult-type nAChR channels and found no difference to that of embryonic-type channels. By double pulse experiments with application of pulses with a saturating concentration of 1 mm acetylcholine (ACh) with increasing duration of the first pulse and a constant interval between pulses we detected a second slow desensitized state which was entered with a time constant of 2835 ms. Recovery from the slow desensitized state proceeded with a single exponential with a time constant of 16134 ms. The experimental data were interpreted by the addition of a transition from the desensitized state with two bound ACh molecules to a slow desensitized state to the well known circular kinetic scheme of activation and desensitization of nAChR channels. This slow desensitized state might play a role in muscle fatigue or in pathological states like myasthenic syndromes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / pharmacology
  • Action Potentials / physiology*
  • Animals
  • Cell Line
  • Humans
  • Mice
  • Receptors, Nicotinic / analysis
  • Receptors, Nicotinic / genetics
  • Receptors, Nicotinic / physiology*
  • Recombinant Proteins / analysis
  • Recombinant Proteins / genetics


  • Receptors, Nicotinic
  • Recombinant Proteins
  • Acetylcholine