TTX Toxin puffer fish

Animal Toxin
THE PUFFER FISH

INTRODUCTION
ABILITY
TOXIN
EFFECT TO HUMAN
REFERENCE

PUFFERFISH

Also known as blowfish, developed their famous “inflatability” because their slow, somewhat clumsy
swimming style makes them vulnerable to predators. In attempt of escape, pufferfish use their highly
elastic stomachs and the ability to quickly ingest huge amounts of water (and even air when
necessary) to turn themselves into a virtually inedible ball several times their normal size. Some
species also have spines on their skin to make them even less palatable.

ABILITY
INFLATION
Pufferfish are slow and clumsy swimmers because they need to combine all their fins (i.e., caudal,
anal, pectoral and dorsal) to move. Although this means they can manoeuvre easily, it reduces their
speed and makes them easy targets. Interestingly, the tail fin of pufferfish can thrust the fish forward
at top speed when needed.

PUFFERFISH POISON
The poison found in pufferfish is a tetrodotoxin (TTX). This is one of the most toxic poisons found in
nature. Most people who eat pufferfish do so intentionally; pufferfish are considered an Asian
delicacy, served in some types of sushi and sashimi. Unless the chef is specially trained to cut the
meat in a particular fashion, the dish may contain a large amount of the toxin. Pufferfish poisoning is
similar to paralytic shellfish poisoning.

contains lethal amounts of the poison
tetrodotoxin in its inner organs,
especially the liver, the ovaries, eyes,
and skin.

TETRADOTOXIN
Tetrodotoxin (TTX) is a potent marine neurotoxin found naturally occurring in some marine
organisms, in this case pufferfish. It is named ‘tetrodotoxin’ as it is most commonly associated with
tetraodon pufferfish., however the fish itself doesn’t create the toxin. A species of bacteria called
Pseudoaltromonas tetraodonis.

The structure of TTX consist of a pyrimidine ring and a positive charge guanidinium group.

MECHANISM
Tetrodotoxin is a sodium channel blocker. It inhibits the firing of action potentials in neurons by
binding to the voltage-gated sodium channels in nerve cell membranes and blocking the passage of
sodium ions (responsible for the rising phase of an action potential) into the neuron.

TOXICITY
TTX is extremely toxic. The toxin can enter the body of a victim by ingestion, injection, or inhalation,
or through abraded skin. The Material Safety Data Sheet for tetrodotoxin lists the oral median lethal
dose (LD50) for mice as 334 μg per kg. Assuming the lethal dose for humans is similar, 25 milligrams
(0.000881 oz) of tetrodotoxin would be expected to kill a 75 kg (170 lb) person. The amount needed
to reach a lethal dose by injection is much smaller, 8 μg per kg, or a little over one-half milligram
(0.00002 oz) to kill a 75 kg (170 lb) person.

EFFECT TO HUMAN
Tetrodotoxin (TTX), a highly selective and potent blocker of voltage-dependent sodium
channels in motor nerves causes skeletal muscle paralysis and death. The toxin is mainly
present in the gonads, liver, intestines, and skin. Its appearance in an organism depends on the
presence of toxin-synthesizing bacteria, including Pseudoalteromonas haloplanktis tetraodonis
and marine bacteria belonging to the genus Vibrio, especially V. alginolyticus.

These bacteria are most frequently and abundantly found in toxic marine animals and are more
capable than other bacteria of producing tetrodotoxin. Tetrodotoxin is used solely as a research
tool for studying voltage-dependent sodium channels.

POISONING SYMPTOM
• Symptoms generally occur 10-45 minutes after eating the pufferfish poison and begin
with numbness and tingling around the mouth, salivation, nausea, and vomiting.
• Symptoms may progress to paralysis, loss of consciousness, and respiratory failure and
can lead to death.

POISONING TREATMENT
• Vomiting should be induced if the poisoned person is awake and alert and has eaten the
fish within 3 hours.
• The person may become paralyzed. Artificial respirations may keep the person alive
until medical attention in a hospital's emergency department is possible.
• Rapidly turn the person onto their side if vomiting occurs.

REFERENCE
1. Lago J, Rodríguez LP, Blanco L, Vieites JM, Cabado AG (2015). "Tetrodotoxin, an
Extremely Potent Marine Neurotoxin: Distribution, Toxicity, Origin and Therapeutical Uses".
Marine Drugs. 13 (10): 6384–406
2. Scheuer PJ (1970). "Toxins from fish and other marine organisms". Advances in Food
Research. 18: 141–61
3. Woodward RB (1964). "The Structure of Tetrodotoxin" (PDF). Pure Appl. Chem. 9 (1): 49–
75
4. Tetrodotoxin (as TTX)". Immediately Dangerous to Life or Health Concentrations (IDLH).
National Institute for Occupational Safety and Health (NIOSH)
5. Baselt RC (2008). Disposition of toxic drugs and chemicals in man (8th ed.). Foster City,
California: Biomedical Publications. pp. 1521–22