neurotoxin

noun

1. A toxin that specifically acts upon neurons, their synapses, or the nervous system in its entirety.

   “There were stretches of days when the lakes were closed because of the algae. It sometimes secreted neurotoxins that could be fatal.”

   “Among those who think of fugu as merely a distant delicacy, knowledge rarely goes beyond the fish’s infamous trait: In the most delicious species, the innards are suffused with the neurotoxin called tetrodotoxin (TTX).”