Which group of chemicals inhibits the enzyme cholinesterase, leading to over-excitation of the nervous system?

Organophosphates inhibit the enzyme cholinesterase, which plays a crucial role in regulating nerve signal transmission. Cholinesterase breaks down the neurotransmitter acetylcholine in the synapses between nerve cells. When organophosphates inhibit this enzyme, acetylcholine accumulates in the synapses, leading to prolonged stimulation of the nervous system. This can result in symptoms such as muscle twitching, respiratory distress, and, in severe cases, can be fatal.

Understanding organophosphates' mechanism of action is important for recognizing the potential risks associated with these chemicals, especially in agricultural and pest control contexts. Other groups of chemicals, while they may affect the nervous system, operate through different mechanisms. For instance, carbamates also inhibit cholinesterase, but their action is reversible. Pyrethroids work by interfering with sodium channels in nerve cells, and neonicotinoids interact with nicotine receptors, which is distinct from the action of organophosphates.