Insects targets

The peripheral pheromone olfactory system in insects targets for species-selective insect control agents... 

Insect Target tissue Role for oetopamine Source of oetopamine Reference... 

The specific nature and composition of the substituents which define the class of compounds also determine the intrinsic potency against cholinesterase inhibition, the efficiency of absorption, and the pattern of metabolism seen in both target insects and mammals. It is misleading to talk of anticholinesterase pesticides as a single group since each compound has individual properties and activity against both insect targets and man. The common property is that these pesticides are very unstable in the environment and must be reapplied for effect or formulated in slow-release products. 

Diversity of Activities on Insect Targets and Routes of Exposure. 4091... 

The organophosphorons insecticides dimethoate and diazinon are mnch more toxic to insects (e.g., housefly) than they are to the rat or other mammals. A major factor responsible for this is rapid detoxication of the active oxon forms of these insecticides by A-esterases of mammals. Insects in general appear to have no A-esterase activity or, at best, low A-esterase activity (some earlier stndies confnsed A-esterase activity with B-esterase activity) (Walker 1994b). Diazinon also shows marked selectivity between birds and mammals, which has been explained on the gronnds of rapid detoxication by A-esterase in mammals, an activity that is absent from the blood of most species of birds (see Section 23.23). The related OP insecticides pirimiphos methyl and pirimiphos ethyl show similar selectivity between birds and mammals. Pyrethroid insecticides are highly selective between insects and mammals, and this has been attributed to faster metabolic detoxication by mammals and greater sensitivity of target (Na+ channel) in insects. 

Resistance to DDT has been developed in many insect species. Although there are some cases of metabolic resistance (e.g., strains high in DDT dehydrochlorinase activity), particular interest has been focused on kdr and super kdr mechanisms based upon aberrant forms of the sodium channel—the principal target for DDT. There are many examples of insects developing resistance to dieldrin. The best-known mechanism is the production of mutant forms of the target site (GABA receptor), which are insensitive to the insecticide. 

Gamma aminobutyric acid (GABA) receptors are located on the postsynaptic membranes of inhibitory synapses of both vertebrates and insects and contain within their membrane-spanning structure a chloride ion channel. They are found in both vertebrate brains and invertebrate cerebral ganglia (sometimes referred to as brains) as well as in insect muscles. Particular attention has been given to one form of this receptor—the GABA-A receptor—as a target for novel insecticides (Eldefrawi and Eldefrawi 1990). It is found both in insect muscle and vertebrate brain. The remainder of this description will be restricted to this form. 

Von Keyserlingk, H.C. and Willis, R.J. (1992). The GABA-activated CL channel in insects as a target for insecticide action—a physiological study. In D. Otto and B. Weber (Eds.) Insecticides Mechanism of Action and Resistance. Andover, U.K. Intercept. 

Laemmli. Specific targeting of insect and vertebrate telomeres with pyrrole and imidazole polyamides. EMBO J. 2001, 20, 3218-3228. 

Biju, V, Muraleedharan, D., Nakayama, K, Shinohara, Y., Itoh, T., Baba, Y. and Ishikawa, M. (2007) Quantum dot-insect neuropeptide conjugates for fluorescence imaging, transfection, and nucleus targeting of living cells. Langmuir, 23, 10254-10261. 

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