END-PLATE ELECTROMYOGRAPHY - USE OF SPECTRAL-ANALYSIS OF END-PLATE NOISE

An automated technique for estimating the channel open time of human e nd-plate acetylcholine receptors (AChR) is described. The method, whic h is based on the power spectral analysis of electromyographic end-pla te noise, is simple and permits a rapid estimation of the dominant ACh R ion channel kinetics. Values of AChR channel open time determined by spectral analysis of end-plate noise in adults (1.23 +/- 0.01 ms at 3 3 degrees C) were consistently shorter than those estimated from the d ecay phase of extracellularly recorded miniature end-plate potentials. The channel open time extracted from the end-plate noise compared wel l with that derived from the analysis of in vitro recorded acetylcholi ne-induced current noise. Therefore, spectral analysis of end-plate no ise may provide a good estimation of the kinetics of the human AChR io n channel. The technique is particularly useful in identifying congeni tal myasthenic syndromes with altered AChR ion channel function. (C) 1 997 John Wiley & Sons, Inc.