Biomaterial Database

Potential-dependent action of Anemonia sulcata toxins III and IV on sodium channels in crayfish giant axons. 1988

A Warashina, and Z Y Jiang, and T Ogura

Department of Physiology, Niigata University School of Medicine, Japan.

Effects of toxins III and IV (ATX III and IV) from the sea anemone Anemonia sulcata on the Na current of crayfish giant axons were studied. Both toxins slowed the inactivation of Na channels, producing a maintained Na current during a depolarizing voltage pulse. Using the intensity of the toxin-induced maintained current as an index for the fraction of Na channels to which toxin is bound, the toxin association and dissociation kinetics were analyzed. The dissociation rate of ATX III was increased by two orders of magnitudes by depolarizing the membrane from -70 to -40 mV. This increase of the dissociation rate caused a marked decrease in the binding rate of ATX III to Na channels in the same potential range. ATX IV exhibited association and dissociation kinetics that had a potential dependency quite similar to that of ATX III in spite of different ionic charge distribution in these two toxins. The results support the view that the potential-dependent kinetics of these toxins are not due to an electrostatic interaction between the ionic charges of toxins and the membrane potential but result from a modulation of the binding energy depending on the gate configuration of the Na channel.

UI	MeSH Term	Description	Entries
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
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
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D003064	Cnidarian Venoms	Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.	Chironex Venoms,Jellyfish Venoms,Nematocyst Venoms,Sea Anemone Venoms,Chironex Venom,Cnidarian Venom,Jellyfish Venom,Portuguese Man-of-War Venom,Sea Anemone Venom,Portuguese Man of War Venom,Venom, Chironex,Venom, Cnidarian,Venom, Jellyfish,Venom, Portuguese Man-of-War,Venom, Sea Anemone,Venoms, Chironex,Venoms, Cnidarian,Venoms, Jellyfish,Venoms, Nematocyst,Venoms, Sea Anemone
D003400	Astacoidea	A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.	Astacus,Crayfish,Procambarus,Astacoideas,Crayfishs
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
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
D001369	Axons	Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.	Axon
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D012615	Sea Anemones	The order Actiniaria, in the class ANTHOZOA, comprised of large, solitary polyps. All species are carnivorous.	Actiniaria,Actiniarias,Anemone, Sea,Anemones, Sea,Sea Anemone