NOVEL FUNCTIONS FOR SUBTYPES OF METABOTROPIC GLUTAMATE RECEPTORS

Metabotropic or ''G-protein coupled'' glutamate receptors (mGluRs) wer e discovered and established as a new type of excitatory amino acid re ceptor by their unique coupling mechanism (phosphoinositide hydrolysis ) and pharmacological characteristics. Recently, the cloning of mGluRs and the availability of selective pharmacological agents has greatly increased knowledge of these receptors. It is now recognized that mGlu Rs are a highly heterogenous family of glutamate receptors with novel molecular structure that are linked to multiple second messenger pathw ays. Members of this family have unique pharmacological properties and function to modulate the presynaptic release of glutamate and the pos tsynaptic sensitivity of the cell to glutamate excitation. New informa tion on mGluRs is elucidating the functions of mGluR subtypes in norma l and pathological aspects of neuronal transmission. Basic knowledge o f the role of specific mGluRs in CNS function and pathologies will fur ther expand in the near future. This knowledge is providing the framew ork for the discovery of novel pharmacological approaches to modulate excitatory amino acid neuronal transmission.