Abstract
Nerve agents are organophosphorus compounds influencing cholinergic nerve transmission via inhibition of acetylcholinesterase (AChE; EC 3.1.1.7). The symptoms of intoxication include nicotinic, muscarinic, and central symptoms.
Cholinesterases (ChEs; AChE and butyrylcholinesterase [BChE] EC 3.1.1.8) are characterized as the main enzymes involved in the toxic effect of these compounds including molecular forms. The activity of both enzymes is influenced by inhibitors and other factors such as their pathological states.
The determination of ChEs is a key diagnostic tool in the diagnosis of poisoning with ChE inhibitors (OPs, nerve agents, and carbamates). For nerve agent intoxication, AChE in red blood cells is more diagnostically important than BChE activity in plasma.
There are several methods for ChE determination; however, the most frequent is the Ellman's method and its modifications based on the hydrolysis of thiocholine esters and after detection of the free SH-group of the released thiocholine. The diagnosis of OP or nerve agent poisoning is based on anamnesis, the clinical status of the intoxicated organism, and on ChE determination in the blood.