Inhibitory Glutamate Receptor Channels and Related Insecticides

Inhibitory glutamate receptors (IGluRs) are members of the "Cys-loop" superfamily of ligand-gated ion channels.They mediate synaptic inhibition in neurons and expressed extrajunctionally in striated muscles.Until now,IGluRs channels are found only in invertebrates,and are therefore ideal insecticide targets with high selectivity.IGluRs are found both in neural and muscle tissues in invertebrates.They may play key roles in regulating swallow,locomotion,sense and juvenile hormone biosynthesis.Most of the knowledge about IGluRs came from studies on nematodes and model insects. All together four α subunits and one β subunit are found in nematodes but it is unknown whether a γ subunit exists.Only α subunit is cloned from insect.IGluRs are most similar to GABA receptors on the function of physiology and pharmacology. However,the amino acid sequences of cloned IGluRs are most similar to those of glycine receptor.The insecticides acting on IGluRs are avermectin/milbemycin,fipronil,a phenylpyrazole insecticide,and nodulisporic acid,a novel indole diterpene.The research progress of IGluRs in physiological function,molecular and pharmacological properties,and the mode of action of related insecticides was reviewed.