Anticholinesterase action of 3-diethylaminophenyl-N-methyl-carbamate methiodide in vitro and in vivo.

The inhibitory effect of 3-diethylaminophenyl-N-methylcarbamate methiodide on rat brain acetylcholinesterase and horse plasma butyrylcholinesterase was studied in vitro. This quaternary carbamate is a more potent inhibitor of acetylcholinesterase than butyrylcholinesterase. Complete inhibition of acetylcholinesterase may be achieved without any inhibition of butyrylcholinesterase, i.e. that 3-diethylaminophenyl-N-methylcarbamate methiodide is a selective inhibitor of acetylcholinesterase. The inhibitory effect of different doses of this compound on plasma and liver butyrylcholinesterase and erythrocyte, brain, heart and diaphragm acetylcholinesterase of the rat was studied in vivo. With increasing doses of carbamate the inhibition of the enzymes in the plasma, erythrocytes, liver, heart, and diaphragm increased while the brain acetylcholinesterase was unaffected. The toxic action of carbamate studied was preferably due to acetylcholin esterase inhibition in the peripheral nervous system and this compound cannot penetrate the blood-brain barrier.