Biomaterial Database

Carbodiimide modification reduces the conductance and increases the tetrodotoxin sensitivity in batrachotoxin-modified sodium channels. 1992

L D Chabala, and O S Andersen

Department of Physiology and Biophysics, Cornell University Medical College, New York, NY 10021.

The relationship between the channel entrance and the tetrodotoxin (TTX) binding site was investigated by chemical modification at the extracellular surface of bilayer-incorporated batrachotoxin-(BTX) modified sodium channels using an impermeant carbodiimide in the presence or absence of exogenous nucleophiles. Two (classes of) groups could be modified such that the open-channel conductance was decreased while TTX binding was unaffected, and TTX did not protect against this modification. Because the final conductance level depends on the exogenous nucleophile, each covalent modification appears to involve a carboxyl group. In addition, a third (carboxyl) group could be modified such that TTX binding affinity was increased. These results suggest that the channel entrance and the TTX binding site are spatially separate, which supports previous suggestions that the mechanism by which guanidinium toxins close sodium channels involves a conformational change subsequent to toxin binding.

UI	MeSH Term	Description	Entries
D008567	Membranes, Artificial	Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.	Artificial Membranes,Artificial Membrane,Membrane, Artificial
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
D002234	Carbodiimides	Compounds with the general formula RN	Carbodiimide
D003028	CME-Carbodiimide		4-(2-((Cyclohexylimidocarbonyl)amino)ethyl)-4-methylmorpholinium,CME Carbodiimide,CMEC,Carbodiimide, CME
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
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
D001496	Batrachotoxins	Batrachotoxin is the 20-alpha-bromobenzoate of batrachotoxin A; they are toxins from the venom of a small Colombian frog, Phyllobates aurotaenia, cause release of acetylcholine, destruction of synaptic vesicles and depolarization of nerve and muscle fibers.	Batrachotoxin B
D013572	Synaptic Vesicles	Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.	Synaptic Vesicle,Vesicle, Synaptic,Vesicles, Synaptic
D013574	Synaptosomes	Pinched-off nerve endings and their contents of vesicles and cytoplasm together with the attached subsynaptic area of the membrane of the post-synaptic cell. They are largely artificial structures produced by fractionation after selective centrifugation of nervous tissue homogenates.	Synaptosome