mGluR1 and mGluR5 receptors signal through Gq/G11 that activates phospholipase C and ultimately produces an increase in inositol trisphosphate and cytosolic Ca2+. More downstream signaling pathways include activation of PKC and modulation of Ca2+ and K+ ion channels. Activation of signaling pathways independent of G-proteins has also been reported.nmGluR5 is predominantly expressed in nervous tissue although expression in several non-neural cell types has also been described. In the brain it is highly expressed in the cortex, basal ganglia and hippocampus.n The mGluR5 receptor is involved in several physiological processes such as neuronal development, induction of long-term potentiation (LTP) and depression (LTD) as well as in pathological disorders such as brain trauma, chronic pain, Parkinson’s and Huntington’s disease.