strychnine

Strychnine is a highly toxic, colorless, bitter, crystalline alkaloid primarily used as a pesticide for killing small vertebrates such as birds and rodents. It was historically used in medicine as a cardiac, respiratory, and digestive stimulant but is no longer employed for therapeutic purposes due to its toxicity. Strychnine acts as a potent neurotoxin by competitively antagonizing glycine receptors in the spinal cord and brainstem. This inhibition of glycine-mediated neurotransmission removes the normal inhibitory control over motor neurons, resulting in severe muscle spasms and convulsions that can lead to death by respiratory failure or exhaustion. Strychnine poisoning can occur through ingestion, inhalation, or injection; only small amounts are needed to cause serious effects or death[1][2][4][6][8].