INSECT GLUTAMATE RECEPTORS

This chapter focuses on the insect glutamate receptors (GluR). Glutamate receptors (GluR) of vertebrate CNS have been cloned and these membrane macromolecules have been implicated in important functions, such as information storage, and in a number of disorders of human brain, including cerebral ischaemia. The chapter gives an overview of recent developments, whilst making some pertinent comments on the various relationships between insect GluR and their counterparts in vertebrates. It reviews some opinions on possible future developments, and examines how insect nerve and muscle preparations might serve as models of GluR function in normal and diseased human brain. The chapter presents a schematic summary of the distribution and types of GluR in insects and provides a better understanding of the biophysical and pharmacological properties of insect GluR, in particular qGluR. The chapter discusses studies of locust muscle, which continue to provide basic information on transmitter receptor function. Although information on the subunit compositions of ionotropic receptors of vertebrate CNS and muscle might lead one to anticipate that insect GluR are hetero-oligomers, available evidence, albeit of a rather scant nature, cannot exclude the possibility that at least some are homo-oligomers. At excitatory nerve-muscle junctions of locust skeletal muscle there are pharmacologically distinct subpopulations of GluR (1–3), which are quisqualate-sensitive, ibotenate-sensitive and aspartatesensitive respectively. The chapter examines that cloning of GluR subunits provides an insight into the distributions of GluR in insects and their developmental relationships. © 1994, Academic Press Limited