@article{fdi:010035698,
  title = {{S}ynergism between insecticides permethrin and propoxur occurs through activation of presynaptic muscarinic negative feedback of acetylcholine release in the insect central nervous system},
  author = {{C}orbel, {V}incent and {S}tankiewicz, {M}. and {B}onnet, {J}ulien and {G}rolleau, {F}. and {H}ougard, {J}ean-{M}arc and {L}apied, {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}lthough synergism between pesticides has been widely documented, the physiological mechanisms by which an insecticide synergizes another remains unclear. {T}oxicological and electrophysiological studies were carried out on two susceptible pest species (the mosquito {C}ulex quinquefasciatus and the cockroach {P}eriplaneta americana) to understand better the physiological process involved in pyrethroid and carbamate interactions. {L}arval bioassays were conducted with the susceptible reference strain {SLAB} of {C}. quinquefasciatus to assess the implication of multifunction oxidases and non-specific esterases in insecticide detoxification and synergism. {R}esults showed that the general theory of synergism (competition between pesticides for a common detoxification enzyme) was unlikely to occur in the {SLAB} strain since the level of synergy recorded between permethrin and propoxur was unchanged in the presence of piperonyl butoxide and tribufos, two inhibitors of oxidases and esterases, respectively (synergism ratios were similar with and without synergists). {W}e also showed that addition of a sub-lethal concentration of nicotine significantly increased the toxicity of permethrin and propoxur at the lower range of the dose-mortality regression lines, suggesting the manifestation of important physiological disruptions at synaptic level. {T}he effects of both permethrin and propoxur were studied on the cercal-afferent giant-interneuron synapses in the terminal abdominal ganglion of the cockroach {P} americana using the single-fibre oil-gap method. {W}e demonstrated that permethrin and propoxur increased drastically the {AC}h concentration within the synaptic cleft, which thereby stimulated a negative feedback of {AC}h release. {A}tropine, a muscarinic receptor antagonist, reversed the effect of permethrin and propoxur mixtures. {T}his demonstrates the implication of the presynaptic muscarinic receptors in the negative feedback regulation process and in synergism. {B}ased on these findings, we propose a cascade of molecular events explaining the occurrence of synergistic effects between pyrethroid and carbamate on many susceptible insects including {C} quinquefasciatus, a mosquito of medical importance. (c) 2006 {E}lsevier {I}nc. {A}ll rights reserved.},
  keywords = {insecticide ; synergism ; pyrethroid carbamate mixture ; synaptic transmission ; acetylcholine ; feedback mechanism ; mosquitoes ; cockroaches},
  booktitle = {},
  journal = {{N}eurotoxicology},
  volume = {27},
  numero = {4},
  pages = {508--519},
  ISSN = {0161-813{X}},
  year = {2006},
  DOI = {10.1016/j.neuro.2006.01.011},
  URL = {https://www.documentation.ird.fr/hor/fdi:010035698},
}