An analysis of the dose‐response relationship at voltage‐clamped frog neuromuscular junctions.

1. Frog neuromuscular junctions were viewed with Nomarski optics and voltage clamped. Agonist was applied ionophoretically and agonist concentrations were measured using a micro‐electrode sensitive to quaternary amines. 2. The dose‐response relationship was studied using the agonists carbamylcholine, suberyldicholine and hydroxyphenyl‐propyltrimethylammonium. 3. With all of these agonists, it appeared that the ACh receptor could be active when either one or two agonist binding sites were occupied. The receptor was much more likely to be active when both sites were occupied. Agonist dissociation constants and receptor activation probabilities were estimated by non‐linear regression techniques for several possible receptor activation schemes.

[1]  J. Changeux,et al.  ON THE NATURE OF ALLOSTERIC TRANSITIONS: A PLAUSIBLE MODEL. , 1965, Journal of molecular biology.

[2]  S. W. Kuffler,et al.  Post‐synaptic potentiation: interaction between quanta of acetylcholine at the skeletal neuromuscular synapse. , 1975, The Journal of physiology.

[3]  P. Adams.  Relaxation experiments using bath‐applied suberyldicholine. , 1977, The Journal of physiology.

[4]  J P Changeux,et al.  On the cooperativity of biological membranes. , 1967, Proceedings of the National Academy of Sciences of the United States of America.

[5]  B Katz,et al.  The binding of acetylcholine to receptors and its removal from the synaptic cleft , 1973, The Journal of physiology.

[6]  M. Anderson,et al.  Fluorescent staining of acetylcholine receptors in vertebrate skeletal muscle , 1974, The Journal of physiology.

[7]  K L Magleby,et al.  Factors affecting the time course of decay of end‐plate currents: a possible cooperative action of acetylcholine on receptors at the frog neuromuscular junction. , 1975, The Journal of physiology.

[8]  U. J. McMahan,et al.  Distribution of acetylcholine receptors in the vicinity of nerve terminals on skeletal muscle of the frog , 1972, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[9]  P. Adams.  An analysis of the dose-response curve at voltage-clamped frog-endplates , 1975, Pflügers Archiv European Journal of Physiology.

[10]  R. Ruff.  A quantitative analysis of local anaesthetic alteration of miniature end‐plate currents and end‐plate current fluctuations. , 1977, The Journal of physiology.

[11]  N. Takeuchi.  Some properties of conductance changes at the end‐plate membrane during the action of acetylcholine , 1963, The Journal of physiology.

[12]  B. Katz,et al.  A comparison of acetylcholine and stable depolarizing agents , 1957, Proceedings of the Royal Society of London. Series B - Biological Sciences.

[13]  M. Kordaš,et al.  An attempt at an analysis of the factors determining the time course of the end‐plate current , 1972 .

[14]  A TAKEUCHI,et al.  On the permeability of end‐plate membrane during the action of transmitter , 1960, The Journal of physiology.

[15]  H. Lester,et al.  Rates and equilibria at the acetylcholine receptor of electrophorus electroplaques. A study of neurally evoked postsynaptic currents and of voltage-jump relaxations , 1977, The Journal of general physiology.

[16]  B. Sakmann,et al.  Single-channel currents recorded from membrane of denervated frog muscle fibres , 1976, Nature.

[17]  David Colquhoun,et al.  The Relation between Classical and Cooperative Models for Drug Action , 1973 .

[18]  H. Wolfson,et al.  Acetylcholine receptor metabolism in a nonfusing muscle cell line. , 1977, The Journal of biological chemistry.

[19]  K. Peper,et al.  Density and dose-response curve of acetylcholine receptors in frog neuromuscular junction , 1975, Nature.

[20]  M. Raftery,et al.  Characterization of Torpedo californica acetylcholine receptor: its subunit composition and ligand-binding properties. , 1976, Cold Spring Harbor symposia on quantitative biology.

[21]  V. E. Dionne.  Characterization of drug iontophoresis with a fast microassay technique. , 1976, Biophysical journal.

[22]  K. Peper,et al.  Acetylcholine receptor: Modification of synaptic gating mechanism after treatment with a disulfide bond reducing agent , 1975, Pflügers Archiv.

[23]  H. Lester,et al.  Relaxation measurements on the acetylcholine receptor. , 1975, Proceedings of the National Academy of Sciences of the United States of America.

[24]  A Karlin,et al.  On the application of "a plausible model" of allosteric proteins to the receptor for acetylcholine. , 1967, Journal of theoretical biology.

[25]  K. Peper,et al.  The acetylcholine sensitivity in the vicinity of the neuromuscular junction of the frog , 1974, Pflügers Archiv.

[26]  S W Kuffler,et al.  The distribution of acetylcholine sensitivity at the post‐synaptic membrane of vertebrate skeletal twitch muscles: iontophoretic mapping in the micron range. , 1975, The Journal of physiology.

[27]  B. Katz,et al.  An analysis of the end‐plate potential recorded with an intra‐cellular electrode , 1951, The Journal of physiology.

[28]  C. Stevens,et al.  Voltage dependence of agonist effectiveness at the frog neuromuscular junction: resolution of a paradox. , 1975, The Journal of physiology.

[29]  R. Purves.  The time course of cellular responses to iontophoretically applied drugs. , 1977, Journal of theoretical biology.

[30]  N. Takeuchi.  Effects of calcium on the conductance change of the end‐plate membrane during the action of transmitter , 1963, The Journal of physiology.

[31]  C. Stevens,et al.  Voltage clamp analysis of acetylcholine produced end‐plate current fluctuations at frog neuromuscular junction , 1973, The Journal of physiology.

[32]  NEUROMUSCULAR TRANSMISSION , 1954, The Journal of the Association of Physicians of India.

[33]  K. Beam.  A quantitative description of end‐plate currents in the presence of two lidocaine derivatives. , 1976, The Journal of physiology.

[34]  H. Lester.  Vulnerability of desensitized or curare-treated acetylcholine receptors to irreversible blockade by cobra toxin. , 1972, Molecular pharmacology.

[35]  K. Peper,et al.  Analysis of cooperativity of drug-receptor interaction by quantitative iontophoresis at frog motor end plates. , 1976, Cold Spring Harbor symposia on quantitative biology.

[36]  J. Changeux,et al.  Some structural properties of the cholinergic receptor protein in its membrane environmental relevant to its function as a pharmacological receptor. , 1976, Cold Spring Harbor symposia on quantitative biology.

[37]  D. Colquhoun,et al.  Effects of inhibitors of the binding of iodinated alpha-bungarotoxin to acetylcholine receptors in rat muscle. , 1976, Molecular pharmacology.

[38]  J. Changeux,et al.  Regulation of binding properties of the nicotinic receptor protein by cholinergic ligands in membrane fragments from Torpedo marmorata. , 1975, Proceedings of the National Academy of Sciences of the United States of America.

[39]  C. Stevens,et al.  Conductance of channels opened by acetylcholine-like drugs in muscle end-plate , 1975, Nature.

[40]  T. Reese,et al.  Functional changes in frog neuromuscular junctions studied with freeze-fracture , 1974, Journal of neurocytology.

[41]  D. Colquhoun.  Mechanisms of drug action at the voluntary muscle endplate. , 1975, Annual review of pharmacology.

[42]  D. Fambrough.  Acetylcholine Receptors , 1974, The Journal of general physiology.