10. Nicotine-Mimics: Mode of Action

Many commonly used insecticides exert their toxic actions by over-stimulating the acetylcholine messenger system that transfers of information between neurons within the nervous system. There are two ways by which insecticides over-stimulate the acetylcholine messenger system. First, inhibition of acetylcholinesterase, as described for the organophosphate and carbamate insecticides, causes natural acetylcholine to accumulate in the […]

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13. Insecticide Resistance-Population Level

Here we see a population of pest insects. If you look closely, several individuals look slightly different. These unique individuals represent the small number of mutant insecticide-resistant individuals that occur normally within any population. In this example, we see the population being treated with a cloud of insecticide such such as an organophosphate or carbamate […]

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12. Insecticide Resistance – Molecular Level

A major disadvantage of insecticide use is the development of resistant pest populations that are no longer controlled by insecticides. Based on our understanding of nervous system functions let us explain the development of insecticide resistant populations and how to manage them. Insecticide resistance occurs from genetic mutations that often result in slight changes in […]

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9. Carbamate Insecticide Action

Unlike organophosphates, that permanently block acetylcholinesterase, carbamate insecticides compete with acetylcholine for the enzyme-binding site. This is known as competitive inhibition. When a carbamate insecticide molecule binds with the binding site of acetylcholinesterase, it is also split in the same manner that we saw for acetylcholine, and the organophosphate insecticides. Part of the carbamate molecule […]

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7. Acetylcholinesterase and Insecticide Inhibition

Insecticides destroy the central nervous system by affecting three molecular targets: the enzyme acetylcholinesterase, acetylcholine receptors of the synaptic sodium channels, and axonal sodium channels. First, we will discuss the organophosphate and carbamate insecticides that inhibit acetylcholinesterase. Acetylcholinesterase acts in association with synaptic sodium channels, The channel consists of five proteins. Two of the five […]

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