Invertebrate gamma-aminobutyric acid receptor (iGABAR) (iGABAR)

Invertebrate gamma-aminobutyric acid receptors (iGABARs) are essential components of the invertebrate central nervous system, serving as the primary mediators of inhibitory neurotransmission (Buckingham, S. D., et al., 2005, 'Invertebrate GABA receptors', Progress in Neurobiology). These receptors are members of the Cys-loop superfamily of ligand-gated ion channels and function as pentameric chloride-selective pores that hyperpolarize neurons upon activation by the neurotransmitter GABA (Sattelle, D. B., et al., 1991, 'GABA receptors of insects', Advances in Insect Physiology). They are of significant pharmacological importance as they are the primary targets for several major classes of insecticides and ectoparasiticides, including phenylpyrazoles like fipronil and the newer isoxazoline class such as fluralaner (Casida, J. E., 2015, 'Golden age of insecticide research and development', Annual Review of Entomology). These compounds typically act as non-competitive antagonists that bind within the channel pore, blocking chloride conductance and causing lethal hyperexcitation of the insect nervous system (Bloomquist, J. R., 2003, 'Chloride channels as tools for developing selective insecticides', Archives of Insect Biochemistry and Physiology). A key feature of these targets is the structural divergence from mammalian GABA-A receptors, which allows for high selective toxicity toward pests and parasites while maintaining safety for vertebrate hosts (Zhao, X., et al., 2003, 'Fipronil: action at the GABA receptor', Pest Management Science). Resistance to these drugs often arises through mutations in the RDL (Resistance to dieldrin) gene, which encodes the principal GABA receptor subunit in many insect species (Ffrench-Constant, R. H., et al., 2000, 'Cyclodiene insecticide resistance: from molecular to population genetics', Annual Review of Entomology). Understanding the molecular pharmacology of iGABARs remains critical for the development of sustainable pest management strategies and novel antiparasitic therapies.

Other names

Invertebrate GABA-gated chloride channelRDL receptorResistance to dieldrin receptorInsect GABA receptorGABA-gated chloride channel

Non-competitive antagonism of the GABA-gated chloride channel, leading to the blockage of inhibitory signals and subsequent over-excitation of the nervous system.