Puffer Fish Toxin
Here is some info about the puffer fish toxin, especially for Fugu lovers.
The toxin is called tetrodotoxin, or more precisely anhydrotetrodotoxin 4-epitetrodotoxin and is about 1200 times deadlier than cyanide. This poison can also be found in other animals such as the Blue-Ringed Octopus, or even some newts. The pufferfish does not create the poison itself; rather it is generated by various genera of bacteria within the fish. The fish obtains the bacteria by eating food containing these bacteria. Pufferfish that are born and grown in captivity do not produce tetrodotoxin until they receive some of the poison-producing bacteria, often by eating tissues from a toxin-producing fish. Also, some fish are more poisonous than others. A poisonous fish has enough poison to kill 30 adults..
Tetrodotoxin is a very potent neurotoxin and shuts down electrical signaling in nerves by binding to the pores of sodium channel proteins in nerve cell membranes. It does not cross the blood-brain barrier, leaving the victim fully conscious while paralyzing the remainder of the body. In animal studies with mice, 8 µg tetrodotoxin per kilogram of body weight killed 50% of the mice. The pufferfish itself has immunity to the poison due to a mutation in the protein sequence of the sodium channel pump on the cell membranes.
Treatment: No known Antidote. Intubate and ventilate till the effects wear off. And stop eating Fugu for a while