Neurotoxins

Do you know whatsome spiders, snakes, scorpions,bees, mussels, and pufferfish have in common? Well, besides, scaring you, these animals have poisons that act on the nervous system.These poisons (called neurotoxins) are used bythe animals for protection against predators or for capturing prey. Thetable below indicates 1) the names of the neurotoxins, 2) the animals fromwhich the neurotoxin comes from and 3) the action of the neurotoxin on aneuron. The word "channel" refers to a type of protein molecule bywhich different ions cross the neuronal membrane.

Now if you ever get bitten or stung by one of theseanimals, at least you will know what is happening to your nervoussystem!!

NameSourceNeuronal Action
agotoxinFunnelWeb SpiderBlocks calcium channels
alpha-bungarotoxinKrait (snake)Blocks acetylcholine (nicotinic) receptor
AnatoxinAlgaeAcetylcholine receptor agonist
ApaminHoney beeBlocks potassium channels
BatrachotoxinPoison Arrow FrogPrevents sodiumchannels from closing
beta-bungarotoxinKrait (snake)Inhibits releaseof ACh at neuromusuclar junction and blocks potassium channels
Botulinum toxinBacteriaBlocks acetylcholine release
BrevetoxinRedTide DinoflagellateActivates sodium channels
CapsaicinCayenne PepperExcites peripheral nerve endings
CharybdotoxinScorpionBlocks potassium channels
CiguatoxinDinoflagellate Opens sodium channels
CobrotoxinCobraBlocks nicotinic receptors
ConotoxinMarineSnailSeveral types: one blocksvoltage-sensitive calcium channels;
one blocks voltage-sensitive sodium channels;
one blocks ACh receptors.
CrotoxinRattlesnakeReduces acetylcholine release
DendrotoxinGreen MambaBlocks voltage-gated potassium channels
Domoic acidBlue musselGlutamate/kainate receptor agonist
ErabutoxinSeaSnakeBlocksacetylcholine (nicotinic) receptors
GonyautoxinDinoflagellateBlocks sodium channels
HolocyclotoxinAustralian paralysis tickInhibitsrelease of acetylcholine
Homobatrachotoxin Pitohui (bird)Activates sodium channels
IberiotoxinScorpionBlocks potassium channels
Jorospider toxinJoro spiderBlocks glutamate receptors
KaliotoxinScorpionBlocks potassium channels
LatrotoxinBlack WidowSpiderEnhances acetylcholine release
maculotoxinBlue-RingedOctopusBlocks sodium channels
NoxiustoxinScorpionBlocks sodium channels
PalytoxinSoft coralActivates sodium channels
PhilanthotoxinPredaceous WaspBlocks glutamatereceptors
PhoneutriatoxinBanana spiderSlows sodium channelinactivation
RobustotoxinFunnel web spiderOpens sodiumchannels
SaxitoxinDinoflagellateBlockssodium channels
Stichodactyla ToxinSea AnemoneBlocksvoltage-gated potassium channels
TaicatoxinAustralian Taipan snakeInhibitsvoltage-gated calcium channels
Tetrodotoxin(TTX)PufferfishBlocks sodium channels
TextilotoxinAustralian common brown snakeBlocksrelease of acetylcholine
Tityustoxin-KBrazilian ScorpionBlocks potassium channels
VersutoxinFunnel web spiderOpens sodiumchannels

A good reference on Neurotoxins is: Trends inNeuroscience, June 1996, supplement.

Also see neurotoxins fromanimals in Australia and Venom Supplies Pty. Ltd. formore information on neurotoxins. There are many chemicalsthat are also toxic to the nervous system: to see some examples of thesematerials, go to the Hazardous and Toxic ChemicalsPage from the Environmental Health Center. From venoms to toxins todrugs describes how poisons can be turned intomedicines.

Just in case you encounter apoisonous snake, make sure you know how to treat andprevent a venomous bite.

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Did you know?

Even though the pufferfish contains the neurotoxin called"tetrodotoxin", it is eaten as a delicacy in Japan.In Japan, this dish is called "fugu". Each fugu chef must have aspecial license to make this food. Nevertheless, a few people do get poisoned from eating thepufferfish if it is prepared incorrectly. Tetrodotoxin is found in theliver, skin and eggs of the pufferfish.
Venomous snakes can be dangerous even after they are dead. In a studypublished in the New England Journal of Medicine, it was reported that 14.7% of thepeople envenomated by rattlesnakes were "bitten" bysnakes that were dead or thought to bedead.

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Try it!

Think you know your neurotoxins? Try this "Match theToxin" worksheet. If youhave trouble or want to check your answers, here is ananswer sheet. Note: both of these pages require thefree AdobeAcrobat Reader

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