How do organophosphate and carbamate insecticides disrupt the nervous system?

Organophosphate and carbamate insecticides disrupt the nervous system by inhibiting acetylcholinesterase, the enzyme responsible for degrading acetylcholine.12

Normally, acetylcholine acts as a vital messenger within the parasympathetic nervous system, but its effects are kept brief because it is rapidly broken down by acetylcholinesterase. By inhibiting this enzyme, these insecticides cause acetylcholine to accumulate at high levels, leading to an overstimulation of the parasympathetic system.12

This disruption results in exaggerated physiological responses, including excessive salivation, lacrimation, urination, defecation, and twitching of skeletal muscles. In cases of severe poisoning, the accumulation of acetylcholine can lead to fatal respiratory depression. Because these chemicals interfere with fundamental biological processes essential for life, their use requires extreme caution to prevent accidental exposure, which poses a significant health risk to humans and other mammals.13