Related Experiment Video
Updated: Oct 25, 2026

Paradigms for Pharmacological Characterization of C. elegans Synaptic Transmission Mutants
Published on: August 18, 2008
Structural Modifications Redirect Phenylpyrazole Ectoparasiticides from the Ion Channel Pore to an Allosteric Site on
Tianhao Zhou1,2, Zihan Cheng2, Honglei Xie3
1Key Laboratory of Subtropical Silviculture, Collaborative Innovation Center of Green Pesticide, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou311300, China.
Abstract:
Phenylpyrazole ectoparasiticides, exemplified by fipronil, act as noncompetitive antagonists of arthropod GABA receptors by blocking the ion channel pore. Here, we investigated the molecular mechanism of the newer phenylpyrazole nicofluprole using Drosophila melanogaster. CRISPR/Cas9-mediated mutagenesis and pharmacological assays showed that A301 substitutions in the pore-forming TM2 helix conferred strong resistance to fipronil but had little effect on nicofluprole sensitivity. In contrast, G335 mutations in TM3 markedly reduced nicofluprole activity. Molecular docking supported these findings, indicating that nicofluprole binds at the transmembrane subunit interface rather than within the central pore, consistent with allosteric modulation. These results demonstrate that structural modification of the phenylpyrazole scaffold can redirect target-site engagement from the pore to an allosteric site, explaining the lack of cross-resistance with traditional pore blockers and expanding strategies for GABA receptor-targeted insecticide design.
More Related Videos
07:16Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
07:51Inhibitory Synapse Formation in a Co-culture Model Incorporating GABAergic Medium Spiny Neurons and HEK293 Cells Stably Expressing GABAA Receptors
Published on: November 14, 2014
Related Concept Videos
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Anthelminthic Agents
Antiepileptic Drugs: GABAergic Pathway Potentiators
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for their...
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
GPCR Desensitization