At the crayfish opener neuromuscular junction, axons branch repeatedly before synapsing onto muscle fibers as varicosities. Excitability of these axons was examined with two-electrode current clamp before and after partial block of Na(+) channels with 1 nM tetrodotoxin. 4-Aminopyridine (200 μM) was added to homogenize nonuniformity in K(+) channel density. The impact of tetrodotoxin was evaluat...

High and low affinity binding sites for tetrodotoxin have been found in rat skeletal muscle cells in vitro using a radiolabeled tetrodotoxin derivative and 22Na+ flux studies. High affinity binding sites for tetrodotoxin (KD(tetrodotoxin) = 1.6 nM) cannot be detected at the myoblast stage. They appear and increase in density as myoblasts fuse into myotubes to reach a maximum binding capacity of...

In this contribution, we propose a new synthetic approach to tetrodotoxin (TTX), one of the most famous marine toxins that, after first preparing functionalized linear substrate, forms cyclohexane core from substrate utilizing our mercuric triflate (Hg(OTf)2)-catalyzed cycloisomerization reaction. The concept was applied synthesis 11-nor-6,7,8-trideoxyTTX and 11-nor-4,9-anhydro-6,7,8-trideoxyTT...

The occurrence of tetrodotoxin (TTX) in sediment from Lake Suwa, Japan, was confirmed by a tissue culture assay, high-performance liquid chromatography, and gas chromatography-mass spectrometry. Altogether, 17 TTX-producing bacteria belonging to five genera were isolated from Lake Suwa and Pond Inokasira. Our results indicate that TTX and TTX-producing bacteria occur even in freshwater environm...

The effects of tetrodotoxin on sinus node activity were studied by direct perfusion through its nutrient artery. Tetrodotoxin suppresses action potentials by blocking sodium entry into the cell. In the open-chest anesthetized dog, direct perfusion of the sinus node artery with tetrodotoxin, 1.0 /xg/ml, caused immediate sinus slowing lasting 12 to 60 minutes. This slowing was not affected by int...