Related Experiment Videos
Avermectin binding in Caenorhabditis elegans. A two-state model for the avermectin binding site
1Merck Sharp & Dohme Research Laboratories, Rahway, NJ 07065.
Biochemical Pharmacology
|July 15, 1989
Summary
Researchers identified specific binding sites for ivermectin (IVM) in the nematode Caenorhabditis elegans. These findings reveal a high-affinity IVM receptor in nematodes, crucial for understanding its mode of action.
Area of Science:
- Pharmacology
- Molecular Biology
- Nematology
Background:
- Ivermectin (IVM) is a widely used antiparasitic drug.
- Its precise molecular targets, especially in nematodes, require further elucidation.
- Understanding IVM's binding characteristics is key to its therapeutic applications.
Purpose of the Study:
- To identify and characterize specific ivermectin binding sites in Caenorhabditis elegans.
- To compare IVM binding in C. elegans with that in mammalian systems.
- To correlate binding affinities with in vivo effects.
Main Methods:
- Radioligand binding assays using [3H]IVM.
- Saturation and kinetic binding analyses.
- Competition assays with avermectin derivatives and neurotransmitters.
- In vivo motility assays.
Main Results:
- Specific, saturable [3H]IVM binding sites were identified in C. elegans membranes with high affinity (Kd = 0.26 nM).
- Binding affinity was significantly higher in C. elegans compared to rat brain membranes.
- In vivo IVM effects correlated with binding affinities, and neurotransmitters did not affect binding.
Conclusions:
- This study provides the first direct evidence of specific ivermectin binding sites in nematodes.
- The characterized high-affinity binding site in C. elegans is critical for understanding ivermectin's anthelmintic mechanism.
- Differences in binding sites suggest potential for species-specific drug development.