Referenced in: none

Automatically associated channels: Kv2.1 , Slo1

Title: 11-Oxo-tetrodotoxin and a specifically labelled 3H-tetrodotoxin.

Authors: B Q Wu, L Yang, C Y Kao, S R Levinson, M Yotsu-Yamashita, T Yasumoto

Journal, date & volume: Toxicon, 1996 Apr , 34, 407-16

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/8735240

Abstract
Tetrodotoxin was oxidized to a hydrated aldehyde, 11-oxo-tetrodotoxin, which shares the specificity of tetrodotoxin for the Na+ channel of the isolated voltage-clamped frog skeletal muscle fiber, but is four to five times more potent. It binds to the solubilized Na+ channel of eel electroplax with a similarly higher potency, because of an equilibrium dissociation constant about 0.25, and a dissociation rate constant 2.4 times slower than those for tetrodotoxin. 11-Oxo-tetrodotoxin can be reduced to regenerate a tetrodotoxin, which is chemically and biologically indistinguishable from the original tetrodotoxin. By reducing with tritiated sodium borohydride, a 3H marker can be inserted regiospecifically to yield 11-[3H]-tetrodotoxin. Because it has a defined specific activity of > 2.5 Ci/mmole, and a 3H marker which does not exchange with solvent proton, 11-[3H]-tetrodotoxin is an ideal tracer for tetrodotoxin. It may enable studies of problems which require higher signals and/or better stability of the marker than those obtainable from currently available tracer Na(+)-channel ligands.