Invertebrate gamma-aminobutyric acid type A receptor (GABA_A receptor)

Invertebrate gamma-aminobutyric acid (GABA) type A receptors are pentameric ligand-gated ion channels that play a fundamental role in mediating fast inhibitory neurotransmission within the nervous systems of insects, arachnids, and nematodes [1]. These receptors are primarily composed of subunits such as RDL (Resistance to dieldrin), which form a chloride-selective pore that opens upon the binding of GABA, resulting in post-synaptic hyperpolarization and the suppression of neuronal firing [2]. They are of immense significance in agriculture and veterinary medicine as the primary targets for several major classes of insecticides and ectoparasiticides, including phenylpyrazoles like fipronil and isoxazolines like fluralaner [3]. These therapeutic agents typically function as non-competitive antagonists that bind within the ion channel pore, effectively blocking chloride conductance and causing lethal hyperexcitation of the parasite's nervous system [4]. While they share structural similarities with mammalian GABA_A receptors, evolutionary divergence has resulted in distinct pharmacological profiles that allow for high selectivity and safety in host species [5]. However, the emergence of target-site mutations, such as those in the RDL gene, poses a continuous challenge for pest management and necessitates the ongoing development of novel modulators [6].

Other names

RDL receptorGABA-gated chloride channelResistance to dieldrin proteinIonotropic GABA receptor

Non-competitive antagonism of the chloride channel pore or allosteric modulation of the receptor complex, leading to the blockage of inhibitory signals.