Abstract
The efficacy of acetylcholine, carbachol and suberyldicholine at the frog neuromuscular junction was estimated by single channel recording. The probability of channel opening at high concentration was found to be >0.9 for each, thus showing (a) that their efficacy is high and (b) that the opening rate for the fully-liganded channel is higher than previously thought.
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References
Adams DJ & Colquhoun D (1983) Current relaxations with high agonist concentrations. Do acetylchonine and suberyldicholine block ion channels in frog muscle? J Physiol 341: 22–23P
Adams PR (1981) Acetylcholine receptor kinetics. J Membrane Biol 58: 161–174
Betz W & Sakmann B (1973) Effects of proteolytic enzymes on function and structure of frog neuromuscular junctions. J Physiol 230: 673–688.
Castillo JD & Katz B Interaction at end-plate receptors between different choline derivatives. Proc Roy Soc B 146: 369–381.
Colquhoun D & Sakmann B (1981) Fluctuations in the microsecond time range of the current through single acetylcholine receptor channels. Nature 294: 464–466.
Colquhoun D & Sakmann B (1983) Bursts of openings in transmitter-activated ion channels. InSingle channel recording. eds. B. Sakmann, E. Neher Plenum Press, New York.
Colquhoun D & Sigworth FJ (1983). Fitting and analysis of single channel records. InSingle channel recording. eds. B. Sakmann & E. Neher. Plenum Press. New York.
Hamill OP, Marty A, Neher E, Sakmann B & Sigworth FJ (1981) Improved patch clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch 391: 85–100.
Hess GP, Cash DJ & Aoshima H (1983) Acetylcholine receptor controlled ion translocation: chemical kinetic investigation of the mechanism. Ann Rev Biophys Bioeng 12: 443–473.
Land BR, Salpeter EE & Selpeter MM (1981) Kinetic parameters for acetylcholine interaction in intact neuromuscular junction. Proc Nat Acad Sci USA 78: 7200–7204
Sakmann B & Adams PR (1979) Biophysical aspects of agonist action at frog endplate. InAdvances in Pharmacology and Therapeutics Vol. 1:Receptors., Ed J. Jacob. Pergamon Press, Oxford.
Sakmann B, Patiak J & Neher E (1980) Single acetylcholine-activated channels show burst kinetics in the presence of desensitizing concentrations of agonist. Nature 286: 71–73.
Sine SM & Steinbach JH (1983) Agonists block current through acetylcholine receptor channels on BC3H1 cells. Biophys J 41: 133a.
Stephenson RP (1956) A modification of receptor theory. Br J Pharmac 11: 379–393.
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Ogden, D.C., Colquhoun, D. The efficacy of agonists at the frog neuromuscular junction studied with single channel recording. Pflugers Arch. 399, 246–248 (1983). https://doi.org/10.1007/BF00656725
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DOI: https://doi.org/10.1007/BF00656725