Which class of pesticides is commonly associated with cholinesterase inhibition?

• A. Organophosphate pesticides
• B. Carbamate pesticides
• C. Neonicotinoids
• D. Pyrethroids

Answer: (A)

Cholinesterase inhibition causes acetylcholine to accumulate at nerve endings, leading to overstimulation of cholinergic receptors and a range of cholinergic symptoms. Organophosphate pesticides are the classic class that inhibits acetylcholinesterase by covalently modifying the enzyme’s active site, often producing long-lasting or essentially irreversible inhibition. This direct mechanism makes them the most commonly associated with cholinesterase inhibition among pesticides.

Carbamates also inhibit acetylcholinesterase but reversibly and typically for a shorter duration, so their inhibition is less prolonged. Neonicotinoids and pyrethroids affect other targets—neonicotinoids act on nicotinic receptors, and pyrethroids disrupt sodium channels—not cholinesterase.