Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Imidacloprid different neonicotinoids

Neonicotinoids do not act as a homogenous class of insecticides. Radioligand receptor binding assays revealed two classes of neonicotinoids described here as competitive and non-competitive , respectively, relative to [ H]imidacloprid. Differences in affinity, mode of displacement, number of binding sites and temperature sensitivity suggest that thiamethoxam binds in a way unique among the commercial neonicotinoids. Metabolic transformation is not relevant for its insecticidal effects. [Pg.67]

The cholinergic system in insects is the main target of insecticides. One class of molecules, the neonicotinoids, induces direct activation of the neuronal nicotinic acetylcholine receptors (nAChRs). In the honey bee these receptors are mainly distributed in the olfactory pathways that link sensory neurons to antennal lobes and mushroom bodies. These structures seem to play an important role in olfactory conditioning. We have previously shown that cholinergic antagonists injected in different parts of the brain impaired the formation and retrieval of olfactory memory. We then advanced the hypothesis that, through the activation of the nAChR, the neonicotinoid imidacloprid (IMI) would lead to facilitation of the memory trace. [Pg.85]

All of these act as agonists on the nAChR, but the potency and agonistic efficacy of each of these neonicotinoids were quite different. The five-membered imidacloprid (7) and the open-chain clothianidin (12) were the most potent neonicotinoids in this Heliothis preparation with an EC50 of 0.3 pM (Table 29.1.4). [Pg.946]

Our studies with aphids clearly suggest that thiamethoxam, like the other examined neonicotoinoids, binds to nicotinic receptors. However, there are clear differences to the other commercial neonicotinoids as documented by a kinetic analysis of competition experiments. While thiamethoxam binds to receptors with nanomolar affinity, micromolar concentrations are required to displace imidacloprid. Further, the interaction between the two compounds is noncompetitive meaning that binding of thiamethoxam reduces the binding capacity of the receptor preparation for imidacloprid but not its affinity. Thiamethoxam shares this unusual mode of inhibition with other neonicotinoids (not commercialized) also featured by an W-Methyl group in die pharmacophore. In the competitive mode, displayed by the other commercial neonicotinoids, the capacity is unchanged, while the affinity is reduced. [Pg.79]

In contrast, the neonicotinoids are not protonated and therefore bind differently, resulting in greater activity on insects than manunals. It is this selective toxicity that has led to extensive use of the neonicotinoids and they represent about 20% of the global insecticide market [34]. Worldwide sales of neonicotinoid insecticides are estimated at 1 billion [35]. Imidacloprid and thiacloprid are examples of neonicotinoid insecticides. [Pg.209]


See other pages where Imidacloprid different neonicotinoids is mentioned: [Pg.536]    [Pg.200]    [Pg.209]    [Pg.134]    [Pg.164]    [Pg.74]    [Pg.555]    [Pg.555]   
See also in sourсe #XX -- [ Pg.56 ]




SEARCH



Imidacloprid

Neonicotinoids

© 2024 chempedia.info