MOLECULAR-BIOLOGY AND ELECTROPHYSIOLOGY OF GLUTAMATE-GATED CHLORIDE CHANNELS OF INVERTEBRATES

In this chapter we summarize the available data on a novel class of li gand-gated anion channels that are gated by the neurotransmitter gluta mate. Glutamate is classically thought to be a stimulatory neurotransm itter, however, studies in invertebrates have proven that glutamate al so functions as an inhibitory ligand. The bulk of studies conducted in vivo have been on insects and crustaceans, where glutamate was first postulated to act on H-receptors resulting in a hyperpolarizing respon se to glutamate. Recently, glutamate-gated chloride channels have been cloned from several nematodes and Drosophila. The pharmacology and el ectrophysiological properties of these channels have been studied by e xpression in Xenopus oocytes. Studies on the cloned channels demonstra te that the invertebrate glutamate-gated chloride channels are the H-r eceptors and represent important targets for the antiparasitic avermec tins.