Reconstituted voltage-sensitive sodium channels from eel electroplax: activation of permeability by quaternary lidocaine, N-bromoacetamide, and N-bromosuccinimide. 1989

E C Cooper, and W S Agnew
Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510.

We have investigated the ion permeability properties of sodium channels purified from eel electroplax and reconstituted into liposomes. Under the influence of a depolarizing diffusion potential, these channels appear capable of occasional spontaneous openings. Fluxes which result from these openings are sodium selective and blocked (from opposite sides of the membrane) by tetrodotoxin (TTX) and moderate concentrations of the lidocaine analogue QX-314. Low concentrations of QX-314 paradoxically enhance this channel-mediated flux. N-bromoacetamide (NBA) and N-bromosuccinimide (NBS), reagents which remove inactivation gating in physiological preparations, transiently stimulate the sodium permeability of inside-out facing channels to high levels. The rise and subsequent fall of permeability appear to result from consecutive covalent modifications of the protein. Titration of the protein with the more reactive NBS can be used to produce stable, chronically active forms of the protein. Low concentrations of QX-314 produce a net facilitation of channel activation by NBA, while higher concentrations produce block of conductance. This suggests that rates of modifications by NBA which lead to the activation of permeability are influenced by conformational changes induced by QX-314 binding.

UI MeSH Term Description Entries
D008012 Lidocaine A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE. Lignocaine,2-(Diethylamino)-N-(2,6-Dimethylphenyl)Acetamide,2-2EtN-2MePhAcN,Dalcaine,Lidocaine Carbonate,Lidocaine Carbonate (2:1),Lidocaine Hydrocarbonate,Lidocaine Hydrochloride,Lidocaine Monoacetate,Lidocaine Monohydrochloride,Lidocaine Monohydrochloride, Monohydrate,Lidocaine Sulfate (1:1),Octocaine,Xylesthesin,Xylocaine,Xylocitin,Xyloneural
D009498 Neurotoxins Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept. Alpha-Neurotoxin,Excitatory Neurotoxin,Excitotoxins,Myotoxin,Myotoxins,Neurotoxin,Alpha-Neurotoxins,Excitatory Neurotoxins,Excitotoxin,Alpha Neurotoxin,Alpha Neurotoxins,Neurotoxin, Excitatory,Neurotoxins, Excitatory
D001974 Bromosuccinimide A brominating agent that replaces hydrogen atoms in benzylic or allylic positions. It is used in the oxidation of secondary alcohols to ketones and in controlled low-energy brominations. (From Miall's Dictionary of Chemistry, 5th ed; Hawley's Condensed Chemical Dictionary, 12th ed,). Succinbromimide,N-Bromosuccinimide,N Bromosuccinimide
D002463 Cell Membrane Permeability A quality of cell membranes which permits the passage of solvents and solutes into and out of cells. Permeability, Cell Membrane
D004557 Electric Organ In about 250 species of electric fishes, modified muscle fibers forming disklike multinucleate plates arranged in stacks like batteries in series and embedded in a gelatinous matrix. A large torpedo ray may have half a million plates. Muscles in different parts of the body may be modified, i.e., the trunk and tail in the electric eel, the hyobranchial apparatus in the electric ray, and extrinsic eye muscles in the stargazers. Powerful electric organs emit pulses in brief bursts several times a second. They serve to stun prey and ward off predators. A large torpedo ray can produce of shock of more than 200 volts, capable of stunning a human. (Storer et al., General Zoology, 6th ed, p672) Electric Organs,Organ, Electric,Organs, Electric
D004593 Electrophorus A genus of fish, in the family GYMNOTIFORMES, capable of producing an electric shock that immobilizes fish and other prey. The species Electrophorus electricus is also known as the electric eel, though it is not a true eel. Eel, Electric,Electric Eel,Electrophorus electricus
D000081 Acetamides Derivatives of acetamide that are used as solvents, as mild irritants, and in organic synthesis.
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012414 Rubidium Radioisotopes Unstable isotopes of rubidium that decay or disintegrate emitting radiation. Rb atoms with atomic weights 79-84, and 86-95 are radioactive rubidium isotopes. Radioisotopes, Rubidium
D012979 Sodium Radioisotopes Unstable isotopes of sodium that decay or disintegrate emitting radiation. Na atoms with atomic weights 20-22 and 24-26 are radioactive sodium isotopes. Radioisotopes, Sodium

Related Publications

E C Cooper, and W S Agnew
January 1983, Cold Spring Harbor symposia on quantitative biology,
E C Cooper, and W S Agnew
September 1987, The Journal of general physiology,
E C Cooper, and W S Agnew
April 1985, Biophysical journal,
E C Cooper, and W S Agnew
November 1983, The Journal of neuroscience : the official journal of the Society for Neuroscience,
E C Cooper, and W S Agnew
March 1977, Proceedings of the National Academy of Sciences of the United States of America,
E C Cooper, and W S Agnew
January 1986, Proceedings of the National Academy of Sciences of the United States of America,
E C Cooper, and W S Agnew
January 1984, Biophysical journal,
Copied contents to your clipboard!