Biomaterial Database

The sodium channel from rat brain. Reconstitution of voltage-dependent scorpion toxin binding in vesicles of defined lipid composition. 1985

D J Feller, and J A Talvenheimo, and W A Catterall

Purified sodium channels incorporated into phosphatidylcholine (PC) vesicles mediate neurotoxin-activated 22Na+ influx but do not bind the alpha-scorpion toxin from Leiurus quinquestriatus (LqTx) with high affinity. Addition of phosphatidylethanolamine (PE) or phosphatidylserine to the reconstitution mixture restores high affinity LqTx binding with KD = 1.9 nM for PC/PE vesicles at -90 mV and 36 degrees C in sucrose-substituted medium. Other lipids tested were markedly less effective. The binding of LqTx in vesicles of PC/PE (65:35) is sensitive to both the membrane potential formed by sodium gradients across the reconstituted vesicle membrane and the cation concentration in the extravesicular medium. Binding of LqTx is reduced 3- to 4-fold upon depolarization to 0 mV from -50 to -60 mV in experiments in which [Na+]out/[Na+]in is varied by changing [Na+]in or [Na+]out at constant extravesicular ionic strength. It is concluded that the purified sodium channel contains the receptor site for LqTx in functional form and that restoration of high affinity, voltage-dependent binding of LqTx by the purified sodium channel requires an appropriate ratio of PC to PE and/or phosphatidylserine in the vesicle membrane.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002412	Cations	Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.	Cation
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
D012604	Scorpion Venoms	Venoms from animals of the order Scorpionida of the class Arachnida. They contain neuro- and hemotoxins, enzymes, and various other factors that may release acetylcholine and catecholamines from nerve endings. Of the several protein toxins that have been characterized, most are immunogenic.	Scorpion Toxin,Scorpion Toxins,Scorpion Venom Peptide,Tityus serrulatus Venom,Scorpion Venom,alpha-Scorpion Toxin,beta-Scorpion Toxin,gamma-Scorpion Toxin,Peptide, Scorpion Venom,Toxin, Scorpion,Toxin, alpha-Scorpion,Toxin, beta-Scorpion,Venom Peptide, Scorpion,Venom, Scorpion,Venom, Tityus serrulatus,alpha Scorpion Toxin,beta Scorpion Toxin,gamma Scorpion Toxin
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23