Metabotropic glutamate (mGlu) receptors represent the largest family of glutamate receptors in
mammals and act as fine tuners of the chemical transmission in central nervous system (CNS).
In the last decade, results concerning the expression and the subcellular localization of mGlu receptors
further clarified their role in physio-pathological conditions. Concomitantly, their pharmacological
characterization largely improved thanks to the identification of new compounds (chemical ligands
and antibodies recognizing epitopic sequences of the receptor proteins) that allowed to decipher the
protein compositions of the naive receptors.
mGlu receptors are expressed at the presynaptic site of chemical synapses. Here, they modulate
intraterminal enzymatic pathways controlling the migration and the fusion of vesicles to synaptic
membranes as well as the phosphorylation of colocalized receptors. Both the control of transmitter
exocytosis and the phosphorylation of colocalized receptors elicited by mGlu receptors are relevant
events that dictate the plasticity of nerve terminals, and account for the main role of presynaptic
mGlu receptors as modulators of neuronal signalling.
The role of the presynaptic mGlu receptors in the CNS has been the matter of several studies and
this review aims at briefly summarizing the recent observations obtained with isolated nerve endings
(we refer to as synaptosomes). We focus on the pharmacological characterization of these receptors
and on their receptor-receptor interaction / oligo-dimerization in nerve endings that could be
relevant to the development of new therapeutic approaches for the cure of central pathologies.