a highly specific Na⁺ channel blocker in excitable tissues.

C₁₁H₁₇N₃O₈ from Fugu Fish organs.

• Molecular Weight : 319.28 Da.
  
  
• Melting Point : does not melt at 200 °C, darkens and turns black with increasing temperature.
  
  
• Solubility in : 2% acetic or citric acid, dilute sulfuric acid; slightly in water, dry alcohol and ether; insoluble in organic solvents.
  
  
• Purity min. : 96 %. (HPLC, IR, NMR)
  
  
• Physical Form : white crystal powder.
  
  
• Biological Activity : KD (cardiac myocytes in rats): 0.8 nM(2)
  * 10-8 M block nervous system; * 10-5 M block heart muscle. The binding to Na
  + channel is reversible. ED50 = 3.7 nM.
  
  
• Toxicity (LD₅₀) : mice (i.v.): 8.7 µg/kg.
  mice (i.p.): 8 - 10 µg/kg.
  mice (s.c.): 11.5 µg/kg.
  
  
• Storage recommendations : stable at room temperature, store preferably at 4°C. Solid and solutions can be kept in deep freeze for a long time without any change in their activity. Solution for use: reconstitute in citrate or acetate buffer, pH 4.8-4.9
  Safety recommendations:
  highly toxic.
  
  
• CAS Reg. No. : 4368-28-9
  
  
• RTECS No. : IO1450000
  
  
• Merck Index 11th Ed. : 9175
  
  
• Bibliography :
  
  1. Abraham et al. "Antiarrhythmic properties of tetrodotoxin against occlusion-induced arrhythmias in the rat: a novel approach to the study of the antiarrhythmic effects of ventricular sodium channel blockade." J. Pharmacol. Exp. Ther. (1989). 251(3):1166
  2. Lombet et al. "A cardiac tetrodotoxin binding component: biochemical identification, characterization and properties." Biochemistry (1981). 20:1279-1285