What is the mechanism of action of strychnine toxicity?

Strychnine toxicity primarily functions through competitive inhibition of postsynaptic glycine receptors. Glycine is an important inhibitory neurotransmitter in the central nervous system, particularly in the spinal cord and brainstem. By blocking these receptors, strychnine prevents the normal inhibitory action of glycine, leading to increased neuronal excitability and resulting in severe muscle spasms and convulsions. This mechanism explains the characteristic clinical signs associated with strychnine poisoning, such as hyperreflexia and spasms throughout the body.

Other potential mechanisms mentioned, such as neurotransmitter release inhibition or interactions with opioid receptors or dopamine transporters, are not applicable to strychnine. This substance specifically targets the glycine receptors, making answer B the correct choice reflecting the precise action of strychnine in the context of its toxic effects on the neurological system.