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Updated: Jul 22, 2026

Physiological Recordings of High and Low Output NMJs on the Crayfish Leg Extensor Muscle
Published on: November 17, 2010
The conductance of the muscle nicotinic receptor channel changes rapidly upon gating
D J Maconochie1, G H Fletcher, J H Steinbach
1Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Abstract:
We have recorded single-channel currents through fetal-type muscle nicotinic receptor channels at recording bandwidths of approximately 50 and 75 kHz. The time course of the rising phase of aligned and averaged openings can be entirely accounted for if it is assumed that the conductance of the single channel changes instantaneously, and that alignment and averaging introduce a dispersion of 2-3 microseconds. We conclude that we find no evidence for a gradual change in conductance as a channel opens or closes. The shapes of averaged power spectra are consistent with this conclusion, insofar as they exclude an exponential relaxation in the transition with a time constant of 10 microseconds or more.
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