Metabotropic glutamate receptors mGluRs

Eight metabotropic glutamate receptors (mGluRs) have been identified that embody three functional classes 282... 

However, overactivation of AMPA or KA receptors can also lead to intracellular Ca2+ overload and neurodegeneration. This maybe especially true under conditions where NMDA-receptor activity is reduced by extracellular acidity or a buildup of extracellular Zn2+ [ 12]. It is also true with respect to specific neuronal subpopulations that express AMPA-sensitive Ca2+ channels (see Ch. 15). G-protein-linked metabotropic glutamate receptors (mGluRs) appear not to mediate excitotoxicity directly but, rather, to modify the degree of excitotoxic injury. 

Macek, T. A., Schaffhauser, H., and Conn, P. J. (1998) Protein kinase C and A3 adenosine receptor activation inhibit presynaptic metabotropic glutamate receptor (mGluR) function and uncouple mGluRs from GTP-binding proteins. J. Neurosci. 18, 6138-6146. 

However, it is not the only mechanism, because drugs that do not work at NMDA receptors can impair memory (e.g., benzodiazepines). Other EAA receptors include the ionotropic AMPA and kainate receptors, and the metabotropic glutamate receptors (mGluR). 

Figure 8. GPCRs described using radar plots. From left to right metastatin receptor (GPR54), neuropeptide Y2 receptor and metabotropic glutamate receptor (mGluRS).

Recent data suggest that a progressive increase in tonic mGluR activity during postnatal development contributes to a reduction of release probability of glutamate in excitatory cortical synapses (Chen and Roper 2004). Group I metabotropic glutamate receptor activation produces a direct excitation of... 

Bonsi R, Cuomo D., De Persis C., Centonze D., Bemardi G., Calabresi P., and Pisani A. (2005). Modulatory action of metabotropic glutamate receptor (mGluR) 5 on mGluRl function in striatal cholinergic interneurons. Neuiopharmacology 49(Suppl 1) 104—113. 

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