Acetylcholine receptor inhibition by d-tubocurarine involves both a competitive and a noncompetitive binding site as determined by stopped-flow measurements of receptor-controlled ion flux in membrane vesicles.

  title={Acetylcholine receptor inhibition by d-tubocurarine involves both a competitive and a noncompetitive binding site as determined by stopped-flow measurements of receptor-controlled ion flux in membrane vesicles.},
  author={Jeffrey W. Karpen and George P. Hess},
  volume={25 7},
The issue of whether d-tubocurarine, the classical acetylcholine receptor inhibitor, inhibits the receptor by a competitive or noncompetitive mechanism has long been controversial. d-Tubocurarine, in this study, has been found to be both a competitive (KC = 120 nM) and a noncompetitive (KNC = 4 microM) inhibitor of receptor-mediated ion flux at zero transmembrane voltage in membrane vesicles prepared from Electrophorus electricus electroplax. A spectrophotometric stopped-flow method, based on… Expand
Kinetics of (+)‐tubocurarine blockade at the neuromuscular junction
The results suggest that Tc binds to the two agonist recognition sites on the nicotinic receptor with equal affinity, and that most of the functional blockade at concentrations up to 5 μm is due to occupancy of only one site. Expand
Spectrophotometric detection of monovalent cation flux in cells: fluorescence microscope measurement of acetylcholine receptor-mediated ion flux in PC-12 cells.
The method has been developed to identify the different neurotransmitter receptors that control the translocation of monovalent cations and to locate the cells in central nervous system cell preparations that contain these receptors. Expand
Interaction of lipopolysaccharide endotoxin produced from Escherichia coli with D-tubocurarine at the nicotinic2 receptor and adenosine 3':5' cyclic monophosphate during physiological contraction in skeletal muscle.
  • J. F. Tomera
  • Biology, Medicine
  • Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
  • 1996
The perturbations of the classical second messenger cAMP system by endotoxin may be responsible for skeletal muscle dysfunction observed in immunocompromised patients. Expand
Structure and Function of the Nicotinic Acetylcholine Receptor
The nicotinic acetylcholine receptor (nAChR) is the prototype of an integral signal transducer: it contains in its protein moiety the binding sites for acetylcholine (ACh) and its agonists andExpand
Snake venom toxins, unlike smaller antagonists, appear to stabilize a resting state conformation of the nicotinic acetylcholine receptor.
The binding of the snake venom toxins does not appear sufficient to induce the resting state conformation in nAChR which have been desensitized by other means, such as solubilization in desensitizing detergents or reconstitution in densitizing lipids. Expand
Determination of the chemical mechanism of neurotransmitter receptor-mediated reactions by rapid chemical kinetic techniques.
Four rapid-mixing techniques for making kinetic measurements in the microsecond and millisecond time regions have now been developed for investigating neurotransmitter receptors in the membranes of neurons and muscle cells, thus extending chemical kinetic approaches to membrane-bound proteins and intercellular processes. Expand
Curare alkaloids from Matis Dart Poison: Comparison with d-tubocurarine in interactions with nicotinic, 5-HT3 serotonin and GABAA receptors
The results reveal that these BBIQAs differ from d-TC in their potencies towards certain Cys-loop receptors, and it is suggested that understanding the reasons behind this might be useful for future drug design. Expand
Nicotinic Acetylcholine Receptors and Low Molecular Weight Toxins
The study of the nicotinic acetylcholine receptor has since its very inception been associated with the use of toxins. The work by Langley in 1905 demonstrated (amongst many important and lastingExpand
Agonist binding to the nicotinic acetylcholine receptor and probability of channel opening
  • H. Prinz
  • Medicine, Chemistry
  • Neurochemistry International
  • 1988
Results are summarized showing that none of these concepts alone is capable of accommodating all experimental observations and a new integrated model based on earlier concepts and the molecular structure of this macromolecule can explain the experiments. Expand
Regulation of Intercellular Signal Transmission. New Approaches to Chemical Kinetic Measurements
My group has been especially interested in developing fast reaction techniques that are suitable for making chemical kinetic measurements with receptor-rich membrane vesicles. More recently we haveExpand


Apparent cooperative effects in acetylcholine receptor-mediated ion flux electroplax membrane preparations.
The results indicate a direct relationship between ligand binding and receptor-mediated ion flux and the dependence of the first-order rate constant, kobs, for 22sodium ion efflux on either decamethonium or carbamylcholine concentration does not exhibit cooperativity. Expand
Acetylcholine receptor: evidence for a regulatory binding site in investigations of suberyldicholine-induced transmembrane ion flux in Electrophorus electricus membrane vesicles.
The minimal kinetic scheme previously presented for acetylcholine and carbamoylcholine, modified by the inclusion of an additional regulatory ligand-binding site for suberyldicholine and characterized by a single dissociation constant, KR, is consistent with the results obtained over a 10 000-fold concentration range of this ligand. Expand
Mechanism of inactivation (desensitization) of acetylcholine receptor. Investigations by fast reaction techniques with membrane vesicles.
The value of the rate constants was determined in a scheme relating the ligand binding steps to ion translocation, and to predict the dependence of these rate constants on carbamylcholine concentration over the 200-fold range investigated. Expand
Interactions of d-tubocurarine with the nicotinic acetylcholine receptor/channel molecule.
The interactions of d-tubocurarine (d-TC) with the ionic channel of the nicotinic acetylcholine receptor were studied by biochemical methods in Torpedo electric organ membranes and byExpand
Equilibrium binding of [3H]tubocurarine and [3H]acetylcholine by Torpedo postsynaptic membranes: stoichiometry and ligand interactions.
It is concluded that dTC binds only to the AcCh sites in Torpedo membranes and that those sites display two affinities for dTC but only one for AcCh, and that the observed competition between those ligands and [3H] AcCh cannot be completely accounted for by competitive interaction with two different affinITIES. Expand
Acetylcholine receptor: evidence for a voltage-dependent regulatory site for acetylcholine. Chemical kinetic measurements in membrane vesicles using a voltage clamp.
At higher concentrations, a concentration-dependent decrease in the ion flux rate was observed without a concomitant change in the inactivation rate, and this inhibitory effect has not been reported previously and was not observed with acetylcholine or carbamoylcholine in the absence of a transmembrane voltage. Expand
Acetylcholine-induced cation translocation across cell membranes and inactivation of the acetylcholine receptor: chemical kinetic measurements in the millisecond time region.
The results support a minimum reaction mechanism previously proposed on the basis of experiments in which carbamylcholine was used and the dependence of the receptor-controlled ion translocation over the concentration range investigated obeys the integrated rate equation based on the proposed mechanism. Expand
Cocaine and phencyclidine inhibition of the acetylcholine receptor: analysis of the mechanisms of action based on measurements of ion flux in the millisecond-to-minute time region.
Chemical kinetic experiments indicate that phencyclidine also increases the rate of receptor inactivation and changes the equilibrium between active and inactive receptor conformations, effects not observed in the presence of cocaine or procaine. Expand
Comparison of acetylcholine receptor-controlled cation flux in membrane vesicles from Torpedo californica and Electrophorus electricus: chemical kinetic measurements in the millisecond region.
AcChoR-controlled cation flux has now been measured in Torpedo californica vesicles by using a pulsed-quench-flow technique with a 2-msec time resolution, and fundamental differences may exist between the mechanism of AcCho R-controlled ion flux in synaptic (Torpedo) and conducting (E. electricus) membranes. Expand
Molecular mechanism of acetylcholine receptor-controlled ion translocation across cell membranes.
  • D. Cash, G. P. Hess
  • Chemistry, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1980
The values of the constants in the rate equation form the basis for predicting receptor-controlled changes in the transmembrane potential of cells and the conditions leading to transmission of signals between cells. Expand