Introduction into mGluR Classifications and Their Classical GProtein Coupled Signaling Pathways

The metabotropic receptors all contain seven transmembrane domains (TM) and are coupled to G-proteins. They are classified into three groups according to their pharmacology (Table 1). Many excellent extensive reviews for the mGluRs are avaible (e.g., refs. 6-9). Metabotropic glutamate receptors are widely expressed in the brain, except for mGluR6, which only occurs in the retina. Group II mGluRs are found in presynaptic membranes or extrasynaptically, group III receptors function as autoreceptors in the presynaptic terminal membrane, and group I mGluRs are often expressed perisy-naptically, near the postsynaptic density (10). Astrocytes can express mGluR3 and mGluR5 (reviewed in ref. 11) and outside the brain, mGluRs occur, for example, in the heart (12). Group I receptors are coupled to Gq-proteins, which, by activating phospholipase C, produce inositol triphosphate (IP3), which then activates the endoplasmic IP3 receptor and triggers the release of calcium from intracellular stores. Group I receptors also activate or inhibit voltage-gated ion channels. Group II and III receptors couple to Gi/G0 proteins that either block adenylate cyclase or calcium channels or activate potassium channels. An example of the different signaling pathways as occurring in the CA1 area of the hippocampus is shown in Fig. 1. The figure also displays the interaction of mGluRs with other receptors and ion channels.

From: Contemporary Clinical Neuroscience: Glutamate and Addiction Edited by: Barbara H. Herman et al. © Humana Press Inc., Totowa, NJ

Table 1

Established and Commonly Used Compounds That Can Distinguish Among mGluR Receptor Groups and Between mGluR1 and mGluR5

Table 1

Established and Commonly Used Compounds That Can Distinguish Among mGluR Receptor Groups and Between mGluR1 and mGluR5

Natural Detox

Natural Detox

Are you looking for a full total body detox? If so, then you might want to try a 10 day detox or some refer to it as the 2-week detox. A 10-day detox is a full body detox that usually means taking several different steps to reach your total body transformation. It might involve a change in diet, exercise and more.

Get My Free Ebook


Post a comment