The Nervous System as Insecticide Target

Most insecticides exert their lethal action by virtue of their effects on the nervous system. The reason for this lies in the special sensitivity of the nervous system, which shows irreversible damage, more so than any other tissue in the body. Poisons which affect other organs of the body commonly produce their ultimate effect on the nervous system. For example, atropine (a heart poison) and carbon monoxide (which blocks the oxygen carrying capacity of the blood) exert their lethal effects by depriving the brain’s essential oxygen requirements, causing brain damage. In order to understand how insecticides exert their toxic effects, it is essential to have some fundamental understanding of the physiology and biochemistry of the mammalian and the insect nervous systems, their similarities and their basic differences. The general features of these systems are depicted in Fig. 8.1. Both systems have two important subdivisions in common, namely, the central nervous system and the peripheral nervous system.