A B $ T R A C T The effect of tetrodotoxin on the sodium currents of the squid (Doryteuthis plei and Sepioteuthis sepiodea) giant axons was studied under potential control conditions. The axons were immersed in artificial seawater at 21°C and pH 7.5. When the effect of the toxin is studied in concentrations ranging from 0.1 to 50 nM the Eadie-Haldane plot is not a straight line and indicates th...

Tetrodotoxin (TTX) is a naturally occurring toxin that has been responsible for human intoxications and fatalities. Its usual route of toxicity is via the ingestion of contaminated puffer fish which are a culinary delicacy, especially in Japan. TTX was believed to be confined to regions of South East Asia, but recent studies have demonstrated that the toxin has spread to regions in the Pacific ...

Tetrodotoxin, a toxic principle of puffer fish poisoning, is one of the most famous marine natural products because of the complex structure having many functional groups and its potent biological activity leading to death. Since the structure elucidation in 1964, this toxin has been recognized as a formidable target molecule for total synthesis. We have recently achieved the first asymmetric t...

We have investigated the effect of electromechanical activity on the molecular forms of acetylcholinesterase (AChE) in cultured embryonic rat myotubes. Both globular and asymmetric forms of AChE are present on the 5th day of culture when myotubes are just beginning to fibrillate. Between days 5 and 8, the 4 S (G1), 10 S (G4), and 16 S (A12) forms increase dramatically, and appreciable 12.5 S (A...

We compared the maximal upstroke velocity of action potentials in short rabbit Purkinje fibers with sodium currents measured with a two-microelectrode voltage clamp. The number of sodium channels available to open during a sudden depolarization was varied either by blockade with tetrodotoxin or by inactivation with steady depolarizations. In both cases, the maximal upstroke velocity was found t...