Fugu (Puffer fish/Blowfish) Sushi, Black Widow Spider Venom And Other Interesting Toxins

Yesterday we had a lecture titled "Neuromuscular Pharmacology" which touched on some interesting toxins:

Fugu sushi is known for its potentially lethal toxicity if it is not prepared correctly. The toxin involved is called tetrodotoxin and is found mainly in the gonads of the fish, although it is also elsewhere in the body. Tetrodotoxin works by blocking voltage-gated sodium channels from the extracellular side. Supposedly fugu sushi gives you a little buzz when you eat it (I don't quite get this-- how does one get a buzz from a toxin that blocks action potentials?)

Saxitoxin is another toxin that works by the same mechanism-- blocking voltage-gated sodium channels. It is found in the single cell algae responsible for the red tide. During red tide, shellfish concentrate this toxin, which can lead to "shellfish paralysis" if the shellfish are consumed.

Latrotoxin is found in black widow spider venom and mediates fusion and release of vesicles containing acetylcholine at the motor neuron terminal even in the absence of calcium-- an impressive phenomenon whose mechanism remains a mystery. After this massive release of acetylcholine there is subsequent decreased synthesis and release of acetylcholine.

No, I don't expect to be treating domestic species for these toxins (with the possible exception of black widow spider bites), they are just illustrations of how toxins work at the neuromuscular junction, which I find pretty cool.