Arthropod glutamate-gated chloride channel (GluCl) (GluCl)

The arthropod glutamate-gated chloride channel (GluCl) is a member of the Cys-loop superfamily of ligand-gated ion channels, found exclusively in invertebrates such as insects, ticks, and nematodes (Hibbs & Gouaux, 2011). These channels mediate fast inhibitory neurotransmission by conducting chloride ions across the postsynaptic membrane in response to the binding of L-glutamate, leading to membrane hyperpolarization and reduced neuronal excitability (Wolstenholme, 2012). Because GluCls are absent in vertebrate species, they serve as a critical and highly selective target for antiparasitic and insecticidal agents, providing a wide margin of safety for the host (Raymond & Sattelle, 2002). Drugs such as ivermectin and other macrocyclic lactones act as potent allosteric agonists, causing prolonged channel opening that results in the flaccid paralysis and eventual death of the parasite. Conversely, newer classes of insecticides like isoxazolines (e.g., fluralaner) act as non-competitive antagonists of these channels, disrupting the balance of inhibitory and excitatory signals (Gassel et al., 2014). In arthropods, these channels are vital for regulating locomotion, feeding behavior, and sensory processing. Mutations in the genes encoding GluCl subunits, particularly the alpha subunit, are frequently associated with the development of resistance to macrocyclic lactones in both agricultural pests and veterinary parasites. While generally safe, certain host species with ABCB1 (MDR1) transporter deficiencies may experience neurotoxicity if these drugs cross the blood-brain barrier and interact with vertebrate GABA receptors (Mealey et al., 2001).

Other names

Glutamate-gated chloride channelGluCl receptorAvermectin-sensitive glutamate-gated chloride channelGluClR

Positive allosteric modulation or direct activation of the channel leading to increased chloride conductance, neuronal hyperpolarization, and flaccid paralysis of the organism; or non-competitive antagonism blocking inhibitory neurotransmission (Wolstenholme, 2012; Raymond & Sattelle, 2002).