Topic: Organophosphate poisoning
Subject: Medicine
What is the mechanism of action in organophosphate poisoning?
Cholinesterase inhibition
Cholinesterase activation
Catecholamine inhibition
Catecholamine activation
Correct Answer :
A. Cholinesterase inhibition
Organophosphate compounds are a diverse group of chemicals used in both domestic and industrial settings. Examples of organophosphates include: insecticides, nerve gases and herbicides. Nerve agents have also been used in battle, notably in Iraq in the 1980s. Additionally, chemical weapons still pose a very real concern in this age of terrorist activity. The primary mechanism of action of organophosphate pesticides is inhibition of acetylcholinesterase (AChE). AChE is an enzyme that degrades the neurotransmitter acetylcholine (ACh) into choline and acetic acid. ACh is found in the central and peripheral nervous system, neuromuscular junctions, and red blood cells (RBCs). Organophosphates inactivate AChE by phosphorylating the serine hydroxyl group located at the active site of AChE. This leads to an increase in the amount of Acetylcholine in the body and a wide variety of reactions.
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