Chapter 46 - Cyanide

Abstract

Chlorinated compounds, cyclodienes such as aldrin and dieldrin, used as insecticides, became available for use in the 1940s. Dichlorodiphenyltrichloroethane (DDT) became available during WWII and was used extensively as an insecticide worldwide. One of the reasons that organochlorines were effective insecticides was their ability to persist in the environment. Because of that persistence, most have been eliminated from use today. Lindane (gamma-hexachlorocyclohexane) and endosulfan are the most biodegradable organochlorines and are still used today. The diphenyl aliphatic organochlorines, such as DDT, affect the peripheral nerves and brain by slowing sodium (Na+) influx and inhibiting potassium (K+) outflow. This results in excess intracellular K+ in the neuron, which partially depolarizes the cell. In the 1980s, the mechanism of toxicity for the cyclodiene organochlorine insecticides was determined. These compounds were found to be non-competitive antagonists acting on the chloride ion channel of the gamma-aminobutyric acid A (GABA) receptor.