Chloride channels as tools for developing selective insecticides.

Area of Science:

• Neuroscience
• Pharmacology
• Entomology

Background:

• Ligand-gated chloride channels are crucial for neuronal inhibition in excitable membranes.
• The gamma-aminobutyric acid (GABA) receptor/chloride ionophore complex is a primary target for existing insecticides like fipronil.
• These insecticides function as antagonists, stabilizing nonconducting channel states and causing hyperexcitation.

Purpose of the Study:

• To investigate the mode of action of silphinenes, plant-derived compounds structurally similar to picrotoxinin.
• To explore potential new target sites for insecticide development within chloride channels.

Main Methods:

• Investigated the antagonism of GABA action on insect neurons.
• Assessed the blockade of GABA-mediated chloride uptake in mouse brain synaptoneurosomes.
• Examined the effects of avermectins on GABA-gated chloride channels in mammals and invertebrates.

Main Results:

• Silphinenes antagonize GABA and noncompetitively block GABA-mediated chloride uptake.
• Avermectins cause tremors in mammals and paralysis/death in invertebrates, potentially via glutamate-gated chloride channels.
• Voltage-sensitive chloride channels, involved in diverse physiological processes, are also potential insecticide targets.

Conclusions:

• Silphinenes represent a novel class of GABA receptor antagonists with potential as insecticides.
• Understanding chloride channel function in invertebrates is crucial for developing new pest control strategies.
• Both ligand-gated and voltage-sensitive chloride channels offer promising avenues for future insecticide discovery.